[{"data":1,"prerenderedAt":3327},["ShallowReactive",2],{"knowledge-page-en-\u002Flearn":3},{"article":4,"posts":5,"relatedPosts":3326},null,[6,292,607,920,1347,1620,1963,2339,2658,3013],{"id":7,"title":8,"author":9,"body":10,"category":278,"cover":279,"description":280,"extension":281,"meta":282,"navigation":283,"path":284,"publishedAt":285,"relatedArticles":286,"seo":289,"stem":290,"updatedAt":4,"__hash__":291},"knowledge_en\u002Fen\u002Flearn\u002Fbase-station-vs-ntrip.md","Own base station vs NTRIP network — which is better?","Yuri",{"type":11,"value":12,"toc":265},"minimark",[13,18,23,27,30,34,37,40,44,185,189,192,199,206,214,218,254,258],[14,15,17],"h2",{"id":16},"how-each-approach-works","How each approach works",[19,20,22],"h3",{"id":21},"own-base-station","Own base station",[24,25,26],"p",{},"You set up a second GNSS receiver at a known or averaged position on site. This receiver stays stationary and transmits corrections to your rover via radio (UHF) or internet (using a caster like Emlid Caster). You control everything — the hardware, the data and the baseline distance.",[24,28,29],{},"The base-rover approach has been the standard in professional surveying for decades. It works anywhere, even without mobile data or internet. The corrections are always fresh and always local because the base is physically close to your work area.",[19,31,33],{"id":32},"ntrip-correction-service","NTRIP correction service",[24,35,36],{},"You connect your rover to an NTRIP server over the internet. The server streams corrections from a network of permanently installed reference stations. You need only one receiver in the field — no base station to set up, survey or monitor.",[24,38,39],{},"Modern NTRIP networks such as GEODNET cover entire countries and continents. VRS technology eliminates the baseline distance problem by generating a virtual reference station next to your rover. The accuracy is comparable to a local base station for most professional applications.",[14,41,43],{"id":42},"head-to-head-comparison","Head-to-head comparison",[45,46,51,68,81,94,107,120,133,146,159,172],"compare-table",{"additionalstyles":47,"items":48,"label":49,"winner":50},"mt-[60px]","Own base station|NTRIP network","Base station and NTRIP comparison","NTRIP network",[52,53,55,62],"compare-row",{"title":54},"Setup time",[56,57,59],"compare-cell",{"status":58},"negative",[24,60,61],{},"15–45 min per job. Set up tripod, level, survey or average base position, configure radio link.",[56,63,65],{"status":64},"positive",[24,66,67],{},"Under 2 minutes. Enter credentials once, connect on every job.",[52,69,71,76],{"title":70},"Hardware cost",[56,72,73],{"status":58},[24,74,75],{},"€800–€5,000+ for a second receiver, tripod, radio and accessories.",[56,77,78],{"status":64},[24,79,80],{},"No additional hardware. One rover is enough.",[52,82,84,89],{"title":83},"Ongoing cost",[56,85,86],{"status":64},[24,87,88],{},"Maintenance only. No monthly fees once hardware is paid for.",[56,90,91],{"status":58},[24,92,93],{},"Monthly or annual subscription. Typically €14–€100\u002Fmonth depending on service and plan.",[52,95,97,102],{"title":96},"Accuracy",[56,98,99],{"status":64},[24,100,101],{},"Best at short baselines (\u003C10 km). Highest absolute accuracy when base is on a known point.",[56,103,104],{"status":64},[24,105,106],{},"Comparable accuracy with VRS. 1–3 cm horizontal in most conditions.",[52,108,110,115],{"title":109},"Works without internet",[56,111,112],{"status":64},[24,113,114],{},"Yes — radio link works anywhere.",[56,116,117],{"status":58},[24,118,119],{},"No — requires mobile data at the rover.",[52,121,123,128],{"title":122},"Coverage area per day",[56,124,125],{"status":58},[24,126,127],{},"Limited to ~10–30 km radius from base. Reposition base for large projects.",[56,129,130],{"status":64},[24,131,132],{},"Unlimited within network coverage. Drive anywhere and corrections follow.",[52,134,136,141],{"title":135},"Works in remote areas",[56,137,138],{"status":64},[24,139,140],{},"Yes — no infrastructure needed.",[56,142,143],{"status":58},[24,144,145],{},"Only where mobile data is available.",[52,147,149,154],{"title":148},"Number of rovers",[56,150,151],{"status":64},[24,152,153],{},"One base can serve multiple rovers simultaneously at no extra cost.",[56,155,156],{"status":58},[24,157,158],{},"Each rover typically needs its own subscription or concurrent connection slot.",[52,160,162,167],{"title":161},"Coordinate traceability",[56,163,164],{"status":64},[24,165,166],{},"Full control — base on known national coordinate point gives legally traceable positions.",[56,168,169],{"status":64},[24,170,171],{},"ETRS89\u002FWGS84 — nationally traceable when applied with correct transformation.",[52,173,175,180],{"title":174},"Risk of downtime",[56,176,177],{"status":64},[24,178,179],{},"Battery and radio issues only — fully within your control.",[56,181,182],{"status":58},[24,183,184],{},"Dependent on mobile data coverage and service uptime.",[14,186,188],{"id":187},"real-cost-comparison","Real cost comparison",[24,190,191],{},"The choice often comes down to economics. Here is a realistic cost model for a professional user working 100 days per year.",[193,194],"cost-comparison",{"additionalstyles":47,"items":195,"title":196,"total":197,"total-label":198},"Second receiver (Emlid RS3 or equivalent)|€2,500||Tripod, pole, radio module|€400||Setup time cost (30 min × 100 days × 3 years × €60\u002Fhr)|€9,000||Maintenance and battery replacement|€300","Own base station — 3-year total cost","~€12,200","3-year total",[193,200],{"additionalstyles":201,"items":202,"title":203,"total":204,"total-label":198,"tone":205},"mt-[30px]","Subscription (€39\u002Fmonth professional plan)|€1,404||No extra hardware|€0||Setup time cost (2 min × 100 days × 3 years × €60\u002Fhr)|€600||Mobile data (typically already included in phone plan)|€0","NTRIP subscription — 3-year total cost","~€2,000","primary",[207,208,211],"card",{"additionalstyles":201,"color":209,"title":210},"orange","The hidden cost of base station setup time",[24,212,213],{},"Setting up and surveying a base station takes 15–45 minutes per day. Over a full working year this adds up to 25–75 hours of non-billable time. At a professional day rate this often exceeds the cost of an NTRIP subscription within the first year.",[14,215,217],{"id":216},"which-is-right-for-your-use-case","Which is right for your use case?",[219,220,221,226,230,234,238,242,246,250],"cards",{"additionalstyles":47},[222,223],"cards-item",{"text":224,"title":225},"Driving between jobs leaves no time to set up a base. NTRIP corrections follow you everywhere within network coverage. No equipment to carry, set up or retrieve.","NTRIP wins — mobile surveyor covering multiple sites per day",[222,227],{"text":228,"title":229},"Working across hundreds of hectares daily. NTRIP covers the entire area without repositioning. Multiple tractors can connect simultaneously with individual subscriptions.","NTRIP wins — precision agriculture on large farmland",[222,231],{"text":232,"title":233},"If you return to the same site every day, a permanent base station on a known point gives maximum traceability and independence from mobile data. NTRIP is simpler and equally accurate for most tasks.","Either works well — large construction site with fixed work area",[222,235],{"text":236,"title":237},"Underground, in forests, at sea or in developing regions where mobile data is unreliable. A base-rover setup with radio link works completely offline.","Own base wins — remote areas without mobile data coverage",[222,239],{"text":240,"title":241},"Both approaches deliver GCP accuracy of 1–3 cm. NTRIP is faster to set up. Own base gives independence from mobile coverage in remote areas.","Either works well — drone mapping with ground control points",[222,243],{"text":244,"title":245},"When the law requires positions traceable to a specific national reference frame point, placing the base on a known monument gives unambiguous traceability.","Own base wins — legal cadastral surveys requiring national reference",[222,247],{"text":248,"title":249},"Managing a base station alone means leaving it unattended. NTRIP eliminates this entirely — one person, one receiver, full RTK accuracy.","NTRIP wins — solo operator",[222,251],{"text":252,"title":253},"One base station serves any number of rovers at no extra cost. With NTRIP, each rover needs its own subscription or concurrent slot.","Own base can win — team of multiple rovers",[14,255,257],{"id":256},"the-practical-answer-for-most-users","The practical answer for most users",[207,259,262],{"additionalstyles":47,"color":260,"title":261},"green","NTRIP is usually the practical choice",[24,263,264],{},"If you have reliable mobile data and work across multiple locations, NTRIP is almost always the more economical and practical choice. The hardware savings alone often pay for several years of subscription. Keep a base station setup as a backup for remote work if needed.",{"title":266,"searchDepth":267,"depth":267,"links":268},"",2,[269,274,275,276,277],{"id":16,"depth":267,"text":17,"children":270},[271,273],{"id":21,"depth":272,"text":22},3,{"id":32,"depth":272,"text":33},{"id":42,"depth":267,"text":43},{"id":187,"depth":267,"text":188},{"id":216,"depth":267,"text":217},{"id":256,"depth":267,"text":257},"learn","learn\u002Fown-base-staation-vs-ntrip-network.webp","Both approaches deliver centimetre-accurate RTK Fix. The right choice depends on how you work, where you work and how often you work. This page gives you everything you need to decide.","md",{},true,"\u002Fen\u002Flearn\u002Fbase-station-vs-ntrip","2026-07-25",[287,288],"\u002Fen\u002Flearn\u002Fwhat-is-ntrip","\u002Fen\u002Flearn\u002Frtk-baseline-length",{"title":8,"description":280},"en\u002Flearn\u002Fbase-station-vs-ntrip","lGC4RVUVL1rEDLaiUVEuLK3PGmoOhYPmliIJsUuvP-4",{"id":293,"title":294,"author":295,"body":296,"category":278,"cover":598,"description":599,"extension":281,"meta":600,"navigation":283,"path":288,"publishedAt":285,"relatedArticles":601,"seo":604,"stem":605,"updatedAt":4,"__hash__":606},"knowledge_en\u002Fen\u002Flearn\u002Frtk-baseline-length.md","How far can you be from the base station?","Wilko",{"type":11,"value":297,"toc":590},[298,302,305,308,328,332,442,446,449,463,469,473,476,479,499,503,506,532,536,542,545,584],[14,299,301],{"id":300},"what-is-baseline-length","What is baseline length?",[24,303,304],{},"The baseline is the straight-line distance between your RTK rover and the reference station providing corrections. In a base-rover setup, that is your own base station. When using an NTRIP correction service, it is the nearest physical reference station in the network.",[24,306,307],{},"The shorter the baseline, the more similar the satellite signals seen by both rover and base — which means corrections are more accurate and Fix is faster. As the baseline grows, atmospheric differences (ionosphere and troposphere) between rover and base increase, making it harder for the receiver to resolve carrier phase ambiguities.",[309,310,311,316,320,324],"text-grid",{"additionalstyles":47},[312,313],"text-grid-item",{"text":314,"title":315},"Fast Fix, centimetre accuracy","0–30 km",[312,317],{"text":318,"title":319},"Slower Fix — use VRS","30–60 km",[312,321],{"text":322,"title":323},"Fix becomes unreliable without VRS","60–100 km",[312,325],{"text":326,"title":327},"Use VRS or another network solution","100 km+",[14,329,331],{"id":330},"practical-limits-by-setup-type","Practical limits by setup type",[333,334,335,354],"table",{},[336,337,338],"thead",{},[339,340,341,345,348,351],"tr",{},[342,343,344],"th",{},"Setup type",[342,346,347],{},"Recommended max",[342,349,350],{},"Absolute max",[342,352,353],{},"Status",[355,356,357,375,392,409,426],"tbody",{},[339,358,359,366,369,372],{},[360,361,362,365],"td",{},[363,364,22],"strong",{}," — Single base, radio or NTRIP",[360,367,368],{},"10–15 km",[360,370,371],{},"~30 km",[360,373,374],{},"Best accuracy",[339,376,377,383,386,389],{},[360,378,379,382],{},[363,380,381],{},"NTRIP network, standard mountpoint"," — Nearest physical station",[360,384,385],{},"20–30 km",[360,387,388],{},"~50 km",[360,390,391],{},"Good in dense networks",[339,393,394,400,403,406],{},[360,395,396,399],{},[363,397,398],{},"NTRIP network, VRS mountpoint"," — Virtual reference station",[360,401,402],{},"Any distance in network",[360,404,405],{},"Network coverage area",[360,407,408],{},"Recommended for >30 km",[339,410,411,417,420,423],{},[360,412,413,416],{},[363,414,415],{},"NTRIP network, no VRS"," — Sparse station coverage",[360,418,419],{},"20 km",[360,421,422],{},"~40 km with degraded accuracy",[360,424,425],{},"Use VRS if available",[339,427,428,434,437,439],{},[360,429,430,433],{},[363,431,432],{},"PPP (Precise Point Positioning)"," — No local base needed",[360,435,436],{},"Global",[360,438,436],{},[360,440,441],{},"Minutes to converge, cm post-fix",[14,443,445],{"id":444},"what-happens-as-baseline-grows","What happens as baseline grows",[24,447,448],{},"Longer baselines introduce three problems that affect RTK performance:",[219,450,451,455,459],{"additionalstyles":47},[222,452],{"text":453,"title":454},"The ionosphere is a layer of charged particles that delays satellite signals. At short baselines, rover and base see nearly identical ionospheric conditions, so corrections cancel out the delay well. Beyond roughly 20–30 km, conditions diverge enough to degrade corrections, especially during high solar activity.","1. Ionospheric decorrelation",[222,456],{"text":457,"title":458},"The lower atmosphere also delays signals based on temperature, pressure and humidity. These vary across terrain. At longer baselines, especially with significant altitude differences between rover and base, tropospheric errors become significant.","2. Tropospheric decorrelation",[222,460],{"text":461,"title":462},"RTK Fix depends on resolving carrier phase ambiguities. At longer baselines, this calculation becomes harder and takes longer, or may not converge at all. The result is Float instead of Fix.","3. Slower ambiguity resolution",[207,464,466],{"additionalstyles":47,"color":209,"title":465},"Watch for this sign",[24,467,468],{},"If you are consistently stuck on Float and your environment is good (open sky, strong signal), long baseline is often the cause. Check the distance to the nearest reference station in your NTRIP sourcetable.",[14,470,472],{"id":471},"how-vrs-solves-long-baselines","How VRS solves long baselines",[24,474,475],{},"VRS (Virtual Reference Station) is a network feature where the NTRIP server computes a synthetic correction stream as if a real base station existed right next to your rover — typically within 1–2 km. It achieves this by interpolating data from multiple physical stations across the network.",[24,477,478],{},"To use VRS, your NTRIP client must send your position (a GGA sentence) to the server. The server uses that position to generate the virtual corrections and streams them back. If GGA is not sent, the VRS cannot generate a local correction and you will receive no data.",[480,481,483,489,494],"requirements",{"additionalstyles":47,"title":482},"VRS setup checklist",[484,485,486],"requirement-item",{},[24,487,488],{},"Enable GGA transmission in your NTRIP client.",[484,490,491],{},[24,492,493],{},"Select a mountpoint labelled VRS, MAC or RTCM3_VRS.",[484,495,496],{},[24,497,498],{},"Ensure you have a Single or Float solution first so GGA contains a valid position.",[14,500,502],{"id":501},"limits-by-device-type","Limits by device type",[24,504,505],{},"Different receivers handle long baselines differently depending on their processing engine and the signals they track.",[219,507,508,512,516,520,524,528],{"additionalstyles":47},[222,509],{"text":510,"title":511},"Multi-band. Use a VRS mountpoint beyond 30 km.","Emlid Reach RS2+ \u002F RS3 \u002F RS4 — ~60 km",[222,513],{"text":514,"title":515},"Pure network rover. VRS is strongly recommended.","Emlid Reach RX \u002F RX2 — ~30 km",[222,517],{"text":518,"title":519},"Advanced engines. VRS or MAC required beyond 30 km.","Trimble \u002F Leica — ~100 km",[222,521],{"text":522,"title":523},"Use an MSM5 mountpoint. Use VRS for longer baselines.","DJI RTK drones — ~30 km",[222,525],{"text":526,"title":527},"Entry-level multi-band receiver. Sensitive to baseline length.","u-blox ZED-F9P — ~20 km",[222,529],{"text":530,"title":531},"Short baselines only. No ionospheric correction.","Single-frequency receivers — ~10 km",[14,533,535],{"id":534},"tips-for-long-baseline-situations","Tips for long baseline situations",[207,537,539],{"additionalstyles":47,"color":260,"title":538},"Use VRS first",[24,540,541],{},"If your NTRIP service offers a VRS or MAC mountpoint, switch to it. This eliminates baseline as a factor entirely and is the single most effective change you can make.",[24,543,544],{},"If VRS is not available or you are using your own base station, these steps help:",[546,547,548,556,563,570,577],"stepper",{"additionalstyles":47},[549,550,553],"stepper-item",{"marker":551,"title":552},"1","Move your base closer",[24,554,555],{},"For own-base setups, the most direct solution is repositioning the base within 10–15 km of your work area.",[549,557,560],{"marker":558,"title":559},"2","Wait for better conditions",[24,561,562],{},"During high solar activity (solar maximum), ionospheric delays increase. Working early morning often gives better results.",[549,564,567],{"marker":565,"title":566},"3","Use a multi-band receiver",[24,568,569],{},"Dual or triple-frequency receivers can model and correct ionospheric delays using the difference between frequencies (L1\u002FL2\u002FL5). Single-frequency receivers cannot.",[549,571,574],{"marker":572,"title":573},"4","Increase initialisation time",[24,575,576],{},"At longer baselines, ambiguity resolution simply takes longer. Give the receiver 5–10 minutes in a stationary position before starting work.",[549,578,581],{"marker":579,"title":580},"5","Check elevation mask",[24,582,583],{},"A 15° elevation mask removes low-elevation satellites that carry the highest atmospheric errors at long baselines.",[207,585,587],{"additionalstyles":47,"color":209,"title":586},"Accuracy degrades with baseline even at Fix",[24,588,589],{},"RTK Fix does not guarantee centimetre accuracy at long baselines. At 50+ km without VRS, horizontal errors of 5–10 cm are common even with a Fix solution. For precision work, always verify with known control points.",{"title":266,"searchDepth":267,"depth":267,"links":591},[592,593,594,595,596,597],{"id":300,"depth":267,"text":301},{"id":330,"depth":267,"text":331},{"id":444,"depth":267,"text":445},{"id":471,"depth":267,"text":472},{"id":501,"depth":267,"text":502},{"id":534,"depth":267,"text":535},"learn\u002Fhow-far-can-you-be-from-the-base-station.webp","Baseline length — the distance between your rover and the nearest reference station — directly affects whether you get RTK Fix, how fast you get it, and how accurate it is. Here is what every RTK user needs to know.",{},[602,603],"\u002Fen\u002Flearn\u002Fwhat-is-vrs","\u002Fen\u002Flearn\u002Fwhat-is-gga",{"title":294,"description":599},"en\u002Flearn\u002Frtk-baseline-length","yeaRAGNaezFD_GcEdCRK8Ash3gctEZjgZw5BfvONNWU",{"id":608,"title":609,"author":9,"body":610,"category":278,"cover":912,"description":913,"extension":281,"meta":914,"navigation":283,"path":915,"publishedAt":285,"relatedArticles":916,"seo":917,"stem":918,"updatedAt":4,"__hash__":919},"knowledge_en\u002Fen\u002Flearn\u002Fwhat-is-geodnet.md","What is GEODNET and how does the network work?",{"type":11,"value":611,"toc":904},[612,616,623,626,644,648,651,683,689,693,696,801,805,808,811,817,821,877,881,884,898],[14,613,615],{"id":614},"what-is-geodnet","What is GEODNET?",[24,617,618,619,622],{},"GEODNET — short for ",[363,620,621],{},"Global Earth Observation Decentralized Network"," — is a worldwide network of GNSS reference stations that continuously receive satellite signals and stream correction data over the internet. Any RTK receiver with an internet connection can tap into this data to achieve centimetre-level positioning accuracy without needing its own base station.",[24,624,625],{},"Unlike traditional government-run networks (such as the US CORS network or the European EUREF network), GEODNET is built and operated by a community of individual station owners distributed across the globe. This model allows rapid expansion and dense coverage at a fraction of the cost of conventional infrastructure.",[309,627,628,632,636,640],{"additionalstyles":47},[312,629],{"text":630,"title":631},"Active reference stations worldwide","5,000+",[312,633],{"text":634,"title":635},"Countries with coverage","100+",[312,637],{"text":638,"title":639},"Horizontal accuracy at Fix","\u003C2 cm",[312,641],{"text":642,"title":643},"Network uptime SLA","99.9%",[14,645,647],{"id":646},"how-the-network-delivers-corrections","How the network delivers corrections",[24,649,650],{},"RTK corrections flow from satellite to your rover through a chain of components. Here is how each step works inside the GEODNET system:",[546,652,653,659,665,671,677],{"additionalstyles":47},[549,654,656],{"marker":551,"title":655},"Satellites transmit signals",[24,657,658],{},"GPS, GLONASS, Galileo, BeiDou and other constellations broadcast ranging signals continuously. Every receiver on Earth — reference stations and rovers alike — picks up the same signals.",[549,660,662],{"marker":558,"title":661},"Reference stations record observations",[24,663,664],{},"GEODNET reference stations are fixed GNSS receivers with precisely surveyed positions. They record every satellite signal and measure the difference between the received signal and what the signal should look like at their known position. This difference is the correction data.",[549,666,668],{"marker":565,"title":667},"Corrections are streamed to the GEODNET server",[24,669,670],{},"Each reference station sends its raw GNSS observations to the GEODNET cloud infrastructure in real time over a standard internet connection. The data is formatted as RTCM3 messages — the universal standard for RTK correction data.",[549,672,674],{"marker":572,"title":673},"The network computes and distributes corrections",[24,675,676],{},"GEODNET's processing software combines data from multiple nearby stations to generate high-quality corrections, including VRS (Virtual Reference Station) data that eliminates the effect of baseline distance. The corrections are distributed via an NTRIP caster — a standard internet streaming protocol for RTK data.",[549,678,680],{"marker":579,"title":679},"Your rover connects and achieves Fix",[24,681,682],{},"Your RTK device connects to the NTRIP caster, authenticates with your service credentials, and receives a continuous stream of corrections matched to your location. The receiver combines these with its own satellite observations to resolve carrier phase ambiguities and achieve centimetre-accurate RTK Fix — typically within 10–60 seconds.",[207,684,686],{"additionalstyles":47,"color":205,"title":685},"What RTCM3 means for you",[24,687,688],{},"RTCM3 is the correction data format used by virtually every modern RTK receiver. If your device supports NTRIP, it supports RTCM3 — which means it works with GEODNET-based correction services without any special configuration.",[14,690,692],{"id":691},"network-scale-and-coverage","Network scale and coverage",[24,694,695],{},"GEODNET has grown faster than any previous GNSS reference network. Coverage is particularly dense in North America, Europe, East Asia and Australia, with rapid expansion across South America, Africa and the Middle East.",[333,697,698,711],{},[336,699,700],{},[339,701,702,705,708],{},[342,703,704],{},"Region",[342,706,707],{},"Coverage",[342,709,710],{},"Station density",[355,712,713,726,738,750,763,776,789],{},[339,714,715,720,723],{},[360,716,717],{},[363,718,719],{},"Western Europe",[360,721,722],{},"Excellent",[360,724,725],{},"Stations typically 20–50 km apart",[339,727,728,733,735],{},[360,729,730],{},[363,731,732],{},"Netherlands",[360,734,722],{},[360,736,737],{},"Among the densest coverage in Europe",[339,739,740,745,747],{},[360,741,742],{},[363,743,744],{},"North America",[360,746,722],{},[360,748,749],{},"Dense in urban and agricultural areas",[339,751,752,757,760],{},[360,753,754],{},[363,755,756],{},"East Asia",[360,758,759],{},"Very good",[360,761,762],{},"Strong in Japan, South Korea, China",[339,764,765,770,773],{},[360,766,767],{},[363,768,769],{},"Australia",[360,771,772],{},"Good",[360,774,775],{},"Urban and coastal areas well-covered",[339,777,778,783,786],{},[360,779,780],{},[363,781,782],{},"South America",[360,784,785],{},"Growing",[360,787,788],{},"Major cities and agricultural zones",[339,790,791,796,798],{},[360,792,793],{},[363,794,795],{},"Africa \u002F Middle East",[360,797,785],{},[360,799,800],{},"Expanding rapidly",[14,802,804],{"id":803},"what-makes-it-decentralized","What makes it decentralized?",[24,806,807],{},"Traditional CORS networks are built and operated by governments or large organisations. They require significant capital investment, lengthy planning processes and centralised maintenance teams. GEODNET takes a different approach.",[24,809,810],{},"Individual station owners — surveyors, farmers, technology enthusiasts and businesses — purchase reference station hardware and install it at their location. The station connects to the internet and streams data to the GEODNET network automatically. Station owners receive compensation for their contribution, creating an economic incentive that drives rapid network expansion.",[207,812,814],{"additionalstyles":47,"color":260,"title":813},"Why this matters for coverage",[24,815,816],{},"Because anyone can add a station, GEODNET expands into areas where government networks have not reached. A farmer in rural Poland or a surveyor in rural Brazil can install a station and simultaneously improve local coverage while contributing to the global network.",[14,818,820],{"id":819},"geodnet-vs-traditional-cors-networks","GEODNET vs traditional CORS networks",[45,822,826,839,851,864],{"additionalstyles":47,"items":823,"label":824,"winner":825},"Traditional CORS network|GEODNET","GEODNET and traditional CORS comparison","GEODNET",[52,827,829,834],{"title":828},"Network ownership",[56,830,831],{"status":58},[24,832,833],{},"Government-controlled, slow to expand.",[56,835,836],{"status":64},[24,837,838],{},"Community-owned, expands rapidly.",[52,840,841,846],{"title":707},[56,842,843],{"status":58},[24,844,845],{},"Often free but limited coverage; sparse in rural and developing regions.",[56,847,848],{"status":64},[24,849,850],{},"Global coverage including rural areas.",[52,852,854,859],{"title":853},"Correction model",[56,855,856],{"status":64},[24,857,858],{},"Long track record and often integrated into official surveying workflows.",[56,860,861],{"status":64},[24,862,863],{},"VRS and multi-station corrections built in.",[52,865,867,872],{"title":866},"Access",[56,868,869],{"status":64},[24,870,871],{},"Often available through public or official services.",[56,873,874],{"status":58},[24,875,876],{},"Accessed through subscription services, but works with any NTRIP-compatible device.",[14,878,880],{"id":879},"how-rtksub-uses-geodnet","How RTKsub uses GEODNET",[24,882,883],{},"RTKsub is a correction service built on GEODNET infrastructure. When you connect your device to RTKsub's NTRIP server, you are receiving corrections derived from GEODNET reference stations — the same global network, delivered through RTKsub's connection management, mountpoint selection and customer support.",[219,885,886,890,894],{"additionalstyles":47},[222,887],{"text":888,"title":889},"RTKsub's primary focus, with excellent GEODNET station density across the Netherlands and surrounding countries.","Netherlands and Europe",[222,891],{"text":892,"title":893},"Because GEODNET is a global network, RTKsub can provide corrections wherever GEODNET has coverage — making it useful for international projects and travelling surveyors.","Worldwide",[222,895],{"text":896,"title":897},"RTKsub exposes different RTCM3 mountpoints optimised for different devices: MSM4 for most receivers, MSM5 for DJI drones, VRS for long-baseline situations, and MSM7 for high-end professional equipment.","Multiple mountpoints",[207,899,901],{"additionalstyles":47,"color":205,"title":900},"One subscription, global coverage",[24,902,903],{},"A single RTKsub subscription gives you access to GEODNET corrections wherever coverage exists — not just in the Netherlands. If you work internationally, your credentials work in any country where GEODNET has stations.",{"title":266,"searchDepth":267,"depth":267,"links":905},[906,907,908,909,910,911],{"id":614,"depth":267,"text":615},{"id":646,"depth":267,"text":647},{"id":691,"depth":267,"text":692},{"id":803,"depth":267,"text":804},{"id":819,"depth":267,"text":820},{"id":879,"depth":267,"text":880},"learn\u002Fwhats-is-geodnet.webp","GEODNET is the world's largest decentralized GNSS reference station network, delivering centimetre-accurate RTK corrections to any device, anywhere on Earth. Understanding how it works helps you get the most from any correction service built on it.",{},"\u002Fen\u002Flearn\u002Fwhat-is-geodnet",[287,602],{"title":609,"description":913},"en\u002Flearn\u002Fwhat-is-geodnet","qFkTBWOEVhhvr4vB0KFcQmVmcNXu_XKb-7P0fts2orc",{"id":921,"title":922,"author":9,"body":923,"category":278,"cover":1340,"description":1341,"extension":281,"meta":1342,"navigation":283,"path":603,"publishedAt":285,"relatedArticles":1343,"seo":1344,"stem":1345,"updatedAt":4,"__hash__":1346},"knowledge_en\u002Fen\u002Flearn\u002Fwhat-is-gga.md","What is GGA and why do I need to enable it?",{"type":11,"value":924,"toc":1330},[925,929,936,944,947,951,954,958,1042,1046,1049,1159,1165,1169,1201,1205,1223,1227,1230,1308,1312],[14,926,928],{"id":927},"what-gga-is","What GGA is",[24,930,931,932,935],{},"GGA stands for ",[363,933,934],{},"Global Positioning System Fix Data",". It is one of several standardised NMEA 0183 sentences — short text strings that GPS and GNSS receivers use to report position and status information. You have probably seen NMEA sentences if you have ever looked at raw receiver output: they begin with a dollar sign and are comma-separated.",[24,937,938,939,943],{},"In the context of NTRIP, GGA has a specific role: it is the sentence your device sends ",[940,941,942],"em",{},"to the server"," — in the opposite direction from the correction data — to tell the server where you are. This is unusual because most NTRIP communication is one-way (server to rover), but VRS requires this two-way exchange.",[24,945,946],{},"GGA does not need to be accurate to centimetre level for NTRIP to work correctly. A Single or Float solution position — accurate to a few metres — is more than sufficient. The server only needs to know which part of the network you are in, not your exact position.",[14,948,950],{"id":949},"what-a-gga-sentence-contains","What a GGA sentence contains",[24,952,953],{},"A typical GGA sentence looks like this. Each comma-separated field carries a specific piece of information:",[955,956],"terminal-box",{"additionalstyles":201,"items":957},"Example GGA sentence|$GPGGA,123519,5230.000,N,00452.000,E,4,09,0.9,25.4,M,46.9,M,,*47",[333,959,960,970],{},[336,961,962],{},[339,963,964,967],{},[342,965,966],{},"Field",[342,968,969],{},"Meaning",[355,971,972,983,993,1003,1012,1022,1032],{},[339,973,974,980],{},[360,975,976],{},[977,978,979],"code",{},"123519",[360,981,982],{},"UTC time — 12:35:19",[339,984,985,990],{},[360,986,987],{},[977,988,989],{},"5230.000,N",[360,991,992],{},"Latitude — 52° 30.000' North (Netherlands)",[339,994,995,1000],{},[360,996,997],{},[977,998,999],{},"00452.000,E",[360,1001,1002],{},"Longitude — 4° 52.000' East",[339,1004,1005,1009],{},[360,1006,1007],{},[977,1008,572],{},[360,1010,1011],{},"Fix quality — 4 = RTK Fixed (see table below)",[339,1013,1014,1019],{},[360,1015,1016],{},[977,1017,1018],{},"09",[360,1020,1021],{},"Number of satellites in use",[339,1023,1024,1029],{},[360,1025,1026],{},[977,1027,1028],{},"0.9",[360,1030,1031],{},"HDOP — horizontal dilution of precision",[339,1033,1034,1039],{},[360,1035,1036],{},[977,1037,1038],{},"25.4,M",[360,1040,1041],{},"Altitude above mean sea level in metres",[19,1043,1045],{"id":1044},"fix-quality-values","Fix quality values",[24,1047,1048],{},"The fix quality field in GGA tells the NTRIP server — and any other system reading the output — what kind of position solution your receiver currently has:",[333,1050,1051,1066],{},[336,1052,1053],{},[339,1054,1055,1058,1060,1063],{},[342,1056,1057],{},"Value",[342,1059,969],{},[342,1061,1062],{},"Typical accuracy",[342,1064,1065],{},"Suitable for VRS?",[355,1067,1068,1084,1099,1114,1129,1143],{},[339,1069,1070,1075,1078,1081],{},[360,1071,1072],{},[977,1073,1074],{},"0",[360,1076,1077],{},"No fix",[360,1079,1080],{},"—",[360,1082,1083],{},"No — position is invalid",[339,1085,1086,1090,1093,1096],{},[360,1087,1088],{},[977,1089,551],{},[360,1091,1092],{},"GPS fix (Single)",[360,1094,1095],{},"2–5 m",[360,1097,1098],{},"Yes — good enough to locate in network",[339,1100,1101,1105,1108,1111],{},[360,1102,1103],{},[977,1104,558],{},[360,1106,1107],{},"DGPS fix",[360,1109,1110],{},"0.5–2 m",[360,1112,1113],{},"Yes",[339,1115,1116,1120,1123,1126],{},[360,1117,1118],{},[977,1119,572],{},[360,1121,1122],{},"RTK Fixed",[360,1124,1125],{},"1–3 cm",[360,1127,1128],{},"Yes — best quality GGA",[339,1130,1131,1135,1138,1141],{},[360,1132,1133],{},[977,1134,579],{},[360,1136,1137],{},"RTK Float",[360,1139,1140],{},"0.1–1 m",[360,1142,1113],{},[339,1144,1145,1150,1153,1156],{},[360,1146,1147],{},[977,1148,1149],{},"6",[360,1151,1152],{},"Dead reckoning",[360,1154,1155],{},"Variable",[360,1157,1158],{},"Depends on accuracy",[207,1160,1162],{"additionalstyles":47,"color":205,"title":1161},"You do not need Fix before sending GGA",[24,1163,1164],{},"A common misunderstanding is that GGA only works when you already have RTK Fix. In fact, a Single solution (quality 1) is perfectly sufficient. Send GGA as soon as your receiver has any valid position — this allows VRS to start generating corrections, which then helps you get Fix.",[14,1166,1168],{"id":1167},"how-gga-enables-vrs","How GGA enables VRS",[546,1170,1171,1177,1183,1189,1195],{"additionalstyles":47},[549,1172,1174],{"marker":551,"title":1173},"Your receiver gets a rough position",[24,1175,1176],{},"Within 30–60 seconds of powering on outdoors, your receiver acquires satellite signals and computes a Single solution — typically accurate to 2–5 metres. This is enough.",[549,1178,1180],{"marker":558,"title":1179},"Your NTRIP client sends GGA to the server",[24,1181,1182],{},"Your client connects to the VRS mountpoint and immediately sends the GGA sentence containing your rough position. Most clients send GGA once on connection and then again every 10–60 seconds to account for movement.",[549,1184,1186],{"marker":565,"title":1185},"The server identifies your location in the network",[24,1187,1188],{},"The VRS server reads the latitude and longitude from your GGA sentence and determines which surrounding physical reference stations apply to your area. This computation takes less than a second.",[549,1190,1192],{"marker":572,"title":1191},"A virtual station is generated near you",[24,1193,1194],{},"The server synthesises an RTCM3 correction stream as if a base station existed 1–2 km from your position. It starts streaming this data back to your client immediately.",[549,1196,1198],{"marker":579,"title":1197},"Your receiver achieves RTK Fixed",[24,1199,1200],{},"With local-quality corrections flowing, your receiver resolves carrier phase ambiguities and reaches Fixed — typically within 10–60 seconds in good sky conditions.",[14,1202,1204],{"id":1203},"when-gga-is-required-vs-optional","When GGA is required vs optional",[219,1206,1207,1211,1215,1219],{"additionalstyles":47},[222,1208],{"text":1209,"title":1210},"Any mountpoint labelled VRS, MAC or a similar network correction type. The server cannot generate a virtual station without your position.","GGA required — VRS mountpoints",[222,1212],{"text":1213,"title":1214},"Some NTRIP services select the closest physical station automatically based on your GGA position, rather than requiring you to choose a mountpoint manually.","GGA required — nearest-station auto-selection",[222,1216],{"text":1217,"title":1218},"When connecting to a fixed mountpoint like RTCM3_NL, the server streams corrections regardless of whether GGA is sent. You can enable GGA for logging purposes but it is not used.","GGA optional — standard single-station mountpoints",[222,1220],{"text":1221,"title":1222},"When using your own base-rover configuration without NTRIP, GGA is not involved in the correction exchange at all.","GGA optional — own base station setups",[14,1224,1226],{"id":1225},"how-to-enable-gga-on-your-device","How to enable GGA on your device",[24,1228,1229],{},"The setting name varies between NTRIP clients, but the function is the same on all of them.",[1231,1232,1234,1249,1263,1272,1282,1292,1302],"device-tabs",{"additionalstyles":47,"items":1233},"Emlid Flow|SW Maps|FieldGenius|Trimble Access|DJI Pilot 2|Lefebure NTRIP|Leica Captivate",[1235,1236,1238],"device-tab",{"name":1237},"Emlid Flow",[24,1239,1240,1241,1244,1245,1248],{},"In ",[363,1242,1243],{},"Correction input → NTRIP",", select your VRS mountpoint and enable ",[363,1246,1247],{},"Send GGA to caster",". Connect after the receiver has a valid Single solution.",[1235,1250,1252],{"name":1251},"SW Maps",[24,1253,1254,1255,1258,1259,1262],{},"Go to ",[363,1256,1257],{},"Settings → NTRIP Client",", select the VRS mountpoint and enable ",[363,1260,1261],{},"Transmit GGA"," before connecting.",[1235,1264,1266],{"name":1265},"FieldGenius",[24,1267,1254,1268,1271],{},[363,1269,1270],{},"Set Up Corrections → RTK via Internet",". Select the VRS source and enable GGA transmission in the data-link settings.",[1235,1273,1275],{"name":1274},"Trimble Access",[24,1276,1277,1278,1281],{},"Enter the VRS mountpoint in ",[363,1279,1280],{},"Survey Style → Rover radio",". Trimble Access sends GGA automatically while NTRIP is active.",[1235,1283,1285],{"name":1284},"DJI Pilot 2",[24,1286,1287,1288,1291],{},"Enter the VRS mountpoint under ",[363,1289,1290],{},"RTK Settings → Custom Network RTK",". DJI sends GGA automatically after it has GPS lock, so configure it outdoors.",[1235,1293,1295],{"name":1294},"Lefebure NTRIP",[24,1296,1297,1298,1301],{},"Enter the caster host, port and VRS mountpoint. Enable ",[363,1299,1300],{},"Send GGA"," and select the receiver or internal GPS as the GGA source.",[1235,1303,1305],{"name":1304},"Leica Captivate",[24,1306,1307],{},"In the internet connection or rover settings, select the VRS mountpoint and enable NMEA GGA output to the NTRIP caster.",[14,1309,1311],{"id":1310},"gga-troubleshooting","GGA troubleshooting",[219,1313,1314,1318,1322,1326],{"additionalstyles":47},[222,1315],{"text":1316,"title":1317},"The connection is established but no corrections are flowing. This almost always means GGA is not being sent — or is being sent with quality 0 (no fix). Enable GGA, ensure the receiver has at least a Single solution, then reconnect.","Connected to VRS but 0 bytes per second",[222,1319],{"text":1320,"title":1321},"If corrections are flowing but Fix takes many minutes, the GGA position may have had low quality at connection time. Disconnect, wait for a better Single solution outdoors, then reconnect.","GGA sent but Fix is very slow",[222,1323],{"text":1324,"title":1325},"Most NTRIP clients send GGA periodically — every 5–60 seconds. The server receives updated positions and adjusts the virtual station to follow you. You do not need to reconnect when moving around the network coverage area.","Moving between areas — does GGA update?",[222,1327],{"text":1328,"title":1329},"GGA contains only your approximate position, altitude, satellite count and fix quality. It contains no personal identifiers; the NTRIP server uses it only to route corrections.","Privacy note",{"title":266,"searchDepth":267,"depth":267,"links":1331},[1332,1333,1336,1337,1338,1339],{"id":927,"depth":267,"text":928},{"id":949,"depth":267,"text":950,"children":1334},[1335],{"id":1044,"depth":272,"text":1045},{"id":1167,"depth":267,"text":1168},{"id":1203,"depth":267,"text":1204},{"id":1225,"depth":267,"text":1226},{"id":1310,"depth":267,"text":1311},"learn\u002Fwhat-is-gga.webp","GGA is a short position message your device sends to the NTRIP server. For standard mountpoints it is optional. For VRS mountpoints it is mandatory — without it the server cannot generate corrections and streams nothing back. This is the single most common reason VRS appears to connect but delivers no Fix.",{},[602,287],{"title":922,"description":1341},"en\u002Flearn\u002Fwhat-is-gga","HFG0RJGp9bO8FHQR5HkzNRVEiSqOCSmiRVEfH3EUQ58",{"id":1348,"title":1349,"author":9,"body":1350,"category":278,"cover":1611,"description":1612,"extension":281,"meta":1613,"navigation":283,"path":1614,"publishedAt":285,"relatedArticles":1615,"seo":1617,"stem":1618,"updatedAt":4,"__hash__":1619},"knowledge_en\u002Fen\u002Flearn\u002Fwhat-is-pdop.md","What is PDOP and why does it matter for RTK?",{"type":11,"value":1351,"toc":1603},[1352,1356,1363,1366,1384,1388,1391,1398,1442,1446,1512,1518,1522,1540,1544,1576,1580,1583,1597],[14,1353,1355],{"id":1354},"what-pdop-means","What PDOP means",[24,1357,1358,1359,1362],{},"PDOP stands for ",[363,1360,1361],{},"Position Dilution of Precision",". It is a number that describes how the geometry of the satellites affects the quality of your position calculation. It does not measure correction quality, mobile signal or receiver hardware. It measures one thing only: whether the satellites are spread across the sky in a useful pattern.",[24,1364,1365],{},"When satellites are distributed widely around the horizon and overhead, the receiver can determine your position confidently. When they are clustered in one part of the sky, small errors in the satellite measurements have a much larger effect on the calculated position.",[309,1367,1368,1372,1376,1380],{"additionalstyles":47},[312,1369],{"text":1370,"title":1371},"Excellent satellite geometry","\u003C 2",[312,1373],{"text":1374,"title":1375},"Good for normal RTK work","2–4",[312,1377],{"text":1378,"title":1379},"Use extra care and verify","4–6",[312,1381],{"text":1382,"title":1383},"Poor geometry — wait if possible","> 6",[14,1385,1387],{"id":1386},"why-satellite-geometry-matters","Why satellite geometry matters",[24,1389,1390],{},"Imagine trying to locate yourself by measuring distance to several landmarks. If all landmarks are in the same direction, a small measuring error can move your estimated position a long way. If the landmarks surround you from different directions, the same error has much less effect.",[24,1392,1393,1394,1397],{},"GNSS works the same way. Your receiver needs signals from several satellites, but the ",[940,1395,1396],{},"number"," of satellites alone is not enough. Ten satellites grouped low in the southern sky can give a worse PDOP than eight satellites distributed evenly across the whole sky.",[45,1399,1403,1416,1429],{"additionalstyles":47,"items":1400,"label":1401,"winner":1402},"Low PDOP|High PDOP","Low and high PDOP comparison","Low PDOP",[52,1404,1406,1411],{"title":1405},"Satellite pattern",[56,1407,1408],{"status":64},[24,1409,1410],{},"Satellites are spread widely across the sky and at different elevations.",[56,1412,1413],{"status":58},[24,1414,1415],{},"Satellites are clustered in one direction or blocked by the environment.",[52,1417,1419,1424],{"title":1418},"Position confidence",[56,1420,1421],{"status":64},[24,1422,1423],{},"Small measurement errors have a limited effect on the final position.",[56,1425,1426],{"status":58},[24,1427,1428],{},"Small measurement errors can produce a much larger position error.",[52,1430,1432,1437],{"title":1431},"RTK behaviour",[56,1433,1434],{"status":64},[24,1435,1436],{},"Fix initialisation is usually faster and more reliable.",[56,1438,1439],{"status":58},[24,1440,1441],{},"Fix can take longer, drop to Float or fail to initialise.",[14,1443,1445],{"id":1444},"pdop-ranges-in-practice","PDOP ranges in practice",[333,1447,1448,1460],{},[336,1449,1450],{},[339,1451,1452,1455,1457],{},[342,1453,1454],{},"PDOP",[342,1456,969],{},[342,1458,1459],{},"What to do",[355,1461,1462,1475,1487,1499],{},[339,1463,1464,1469,1472],{},[360,1465,1466],{},[363,1467,1468],{},"Below 2",[360,1470,1471],{},"Excellent geometry",[360,1473,1474],{},"Ideal for survey, stakeout and control measurements.",[339,1476,1477,1481,1484],{},[360,1478,1479],{},[363,1480,1375],{},[360,1482,1483],{},"Good geometry",[360,1485,1486],{},"Suitable for normal RTK work.",[339,1488,1489,1493,1496],{},[360,1490,1491],{},[363,1492,1379],{},[360,1494,1495],{},"Marginal geometry",[360,1497,1498],{},"Check your result on a known point and avoid critical measurements if you can wait.",[339,1500,1501,1506,1509],{},[360,1502,1503],{},[363,1504,1505],{},"Above 6",[360,1507,1508],{},"Poor geometry",[360,1510,1511],{},"Wait for the satellite pattern to improve, or move to a clearer location.",[207,1513,1515],{"additionalstyles":47,"color":205,"title":1514},"PDOP is not an accuracy value",[24,1516,1517],{},"A PDOP of 2 does not mean your position is accurate to 2 centimetres or 2 metres. It is a quality indicator for geometry. RTK accuracy still depends on corrections, baseline length, multipath, receiver quality and whether you have a genuine Fixed solution.",[14,1519,1521],{"id":1520},"what-causes-high-pdop","What causes high PDOP?",[219,1523,1524,1528,1532,1536],{"additionalstyles":47},[222,1525],{"text":1526,"title":1527},"Obstructions remove satellites from parts of the sky. A narrow street, forest edge or steep valley can leave your receiver with satellites only in one direction.","Buildings, trees and terrain",[222,1529],{"text":1530,"title":1531},"Satellite positions change continuously. A poor geometry window at 10:00 can become excellent 30 minutes later without you changing anything.","Time of day",[222,1533],{"text":1534,"title":1535},"GPS-only tracking gives the receiver fewer geometry options. Enable GLONASS, Galileo and BeiDou when your receiver and correction stream support them.","Limited constellations",[222,1537],{"text":1538,"title":1539},"A high elevation mask excludes low satellites. This can reduce multipath, but it can also leave too few satellites for a strong geometry pattern.","An aggressive elevation mask",[14,1541,1543],{"id":1542},"how-to-improve-pdop-in-the-field","How to improve PDOP in the field",[546,1545,1546,1552,1558,1564,1570],{"additionalstyles":47},[549,1547,1549],{"marker":551,"title":1548},"Move to a clearer sky view",[24,1550,1551],{},"Step away from walls, machinery, tree canopies and building overhangs. Even a few metres can reveal satellites that were previously blocked.",[549,1553,1555],{"marker":558,"title":1554},"Enable every available constellation",[24,1556,1557],{},"Use GPS, GLONASS, Galileo and BeiDou where possible. More constellations give the receiver more satellites to form a good geometry pattern.",[549,1559,1561],{"marker":565,"title":1560},"Wait for the geometry window",[24,1562,1563],{},"If PDOP remains high in open sky, wait 15–30 minutes and check again. The satellite configuration changes naturally throughout the day.",[549,1565,1567],{"marker":572,"title":1566},"Review your elevation mask",[24,1568,1569],{},"In open sky, an elevation mask around 10–15° is a practical starting point. Raising it too far can unnecessarily remove useful satellites.",[549,1571,1573],{"marker":579,"title":1572},"Verify critical work on known control",[24,1574,1575],{},"When PDOP is marginal, check a known point before collecting high-consequence measurements. A Fixed status alone is not a substitute for verification.",[14,1577,1579],{"id":1578},"pdop-hdop-and-vdop","PDOP, HDOP and VDOP",[24,1581,1582],{},"PDOP is the combined three-dimensional geometry value. You may also see two related values in your receiver status screen:",[219,1584,1585,1589,1593],{"additionalstyles":47},[222,1586],{"text":1587,"title":1588},"Describes the geometry for latitude and longitude. It matters most for mapping, stakeout and horizontal control.","HDOP — Horizontal Dilution of Precision",[222,1590],{"text":1591,"title":1592},"Describes the geometry for height. It is usually higher than HDOP because vertical GNSS measurements are naturally less well constrained.","VDOP — Vertical Dilution of Precision",[222,1594],{"text":1595,"title":1596},"Combines horizontal and vertical geometry into one overall indicator. It is the value most field applications display by default.","PDOP — Position Dilution of Precision",[207,1598,1600],{"additionalstyles":47,"color":260,"title":1599},"A practical rule: do not chase a perfect number",[24,1601,1602],{},"For most RTK work, a PDOP below 4 with a stable Fixed solution, good corrections and an open sky view is entirely practical. Use PDOP as a warning signal and a planning tool — not as the only quality check.",{"title":266,"searchDepth":267,"depth":267,"links":1604},[1605,1606,1607,1608,1609,1610],{"id":1354,"depth":267,"text":1355},{"id":1386,"depth":267,"text":1387},{"id":1444,"depth":267,"text":1445},{"id":1520,"depth":267,"text":1521},{"id":1542,"depth":267,"text":1543},{"id":1578,"depth":267,"text":1579},"learn\u002Fwhat-is-pdop.webp","PDOP measures the geometry of the satellites your receiver can see. A low PDOP means a strong, well-spread satellite pattern and more reliable RTK positions; a high PDOP means the same signals produce less certain results.",{},"\u002Fen\u002Flearn\u002Fwhat-is-pdop",[1616,603],"\u002Fen\u002Flearn\u002Ffloat-vs-fix",{"title":1349,"description":1612},"en\u002Flearn\u002Fwhat-is-pdop","5c162tbZmsNiSXL_1NVOC59NXuH-qpiRg5RQ8G8jwBU",{"id":1621,"title":1622,"author":295,"body":1623,"category":278,"cover":1955,"description":1956,"extension":281,"meta":1957,"navigation":283,"path":1958,"publishedAt":285,"relatedArticles":1959,"seo":1960,"stem":1961,"updatedAt":4,"__hash__":1962},"knowledge_en\u002Fen\u002Flearn\u002Fwhat-is-rtcm.md","What is RTCM and which version do I need?",{"type":11,"value":1624,"toc":1944},[1625,1629,1636,1639,1642,1659,1663,1666,1691,1697,1701,1708,1711,1825,1829,1832,1835,1839,1842,1846,1849,1855,1859,1862,1888,1892,1895,1898,1901,1904,1938],[14,1626,1628],{"id":1627},"what-is-rtcm","What is RTCM?",[24,1630,1631,1632,1635],{},"RTCM stands for ",[363,1633,1634],{},"Radio Technical Commission for Maritime Services"," — the organisation that defined the standard format for transmitting GNSS correction data between a reference station and a rover. Despite the maritime origin, RTCM is used everywhere: surveying, agriculture, drones, autonomous vehicles and construction.",[24,1637,1638],{},"When your RTK receiver connects to an NTRIP server, the server streams a continuous series of RTCM messages. Each message contains correction data for a specific satellite system (GPS, GLONASS, Galileo, BeiDou) or for specific information types (satellite orbits, clock errors, phase biases). Your receiver reads these messages and applies the corrections to its own satellite observations to compute a centimetre-accurate position.",[24,1640,1641],{},"RTCM is an open standard. This means any receiver that claims RTCM support will work with any RTCM-compatible correction service — regardless of brand.",[309,1643,1644,1648,1652,1655],{"additionalstyles":47},[312,1645],{"text":1646,"title":1647},"The current correction-data standard","RTCM3",[312,1649],{"text":1650,"title":1651},"Modern multi-signal message format","MSM",[312,1653],{"text":1654,"title":572},"Main MSM levels you will encounter",[312,1656],{"text":1657,"title":1658},"Works across compatible brands","Open",[14,1660,1662],{"id":1661},"rtcm2-vs-rtcm3","RTCM2 vs RTCM3",[24,1664,1665],{},"There are two major versions of the RTCM standard. The difference matters for older equipment.",[219,1667,1668,1680],{"additionalstyles":47},[207,1669,1672,1675],{"additionalstyles":1670,"color":209,"title":1671},"h-full","RTCM 2.x — Legacy",[24,1673,1674],{},"Developed in the 1990s. Supports GPS only (no GLONASS, Galileo or BeiDou). Uses a fixed message structure that wastes bandwidth. Still found on very old receivers — pre-2010 equipment.",[24,1676,1677],{},[363,1678,1679],{},"Not recommended",[207,1681,1683,1686],{"additionalstyles":1670,"color":260,"title":1682},"RTCM 3.x — Current standard",[24,1684,1685],{},"Introduced in 2004, continuously updated. Supports all satellite constellations. Uses efficient binary encoding. Includes MSM (Multiple Signal Messages) for multi-frequency data. Used by every modern receiver and correction service.",[24,1687,1688],{},[363,1689,1690],{},"Use this",[207,1692,1694],{"additionalstyles":47,"color":205,"title":1693},"Which version do you have?",[24,1695,1696],{},"If your receiver was manufactured after 2010 and supports multi-constellation GNSS, it uses RTCM3. You do not need to think about RTCM2 unless you are working with genuinely old hardware.",[14,1698,1700],{"id":1699},"msm-types-explained-msm4-msm5-msm7","MSM types explained — MSM4, MSM5, MSM7",[24,1702,1703,1704,1707],{},"Within RTCM3, the most important message type for modern RTK is MSM — ",[363,1705,1706],{},"Multiple Signal Messages",". MSM messages carry satellite observations in a compact, extensible format that supports all constellations and multiple frequencies simultaneously.",[24,1709,1710],{},"There are several MSM levels. The three you will encounter in NTRIP sourcetables are MSM4, MSM5 and MSM7.",[333,1712,1713,1729],{},[336,1714,1715],{},[339,1716,1717,1720,1723,1726],{},[342,1718,1719],{},"Type",[342,1721,1722],{},"Data included",[342,1724,1725],{},"Bandwidth",[342,1727,1728],{},"Best for",[355,1730,1731,1750,1769,1788,1807],{},[339,1732,1733,1738,1741,1744],{},[360,1734,1735],{},[363,1736,1737],{},"MSM4",[360,1739,1740],{},"Pseudorange + carrier phase (compressed)",[360,1742,1743],{},"Low",[360,1745,1746,1749],{},[363,1747,1748],{},"Recommended"," — Most receivers: Emlid, u-blox, generic NTRIP clients",[339,1751,1752,1757,1760,1763],{},[360,1753,1754],{},[363,1755,1756],{},"MSM5",[360,1758,1759],{},"MSM4 data + Doppler observations",[360,1761,1762],{},"Medium",[360,1764,1765,1768],{},[363,1766,1767],{},"DJI required"," — DJI drones and some high-rate applications",[339,1770,1771,1776,1779,1782],{},[360,1772,1773],{},[363,1774,1775],{},"MSM7",[360,1777,1778],{},"Full precision pseudorange + carrier phase (extended)",[360,1780,1781],{},"High",[360,1783,1784,1787],{},[363,1785,1786],{},"High-end"," — Trimble, Leica, Septentrio and survey-grade receivers",[339,1789,1790,1795,1798,1801],{},[360,1791,1792],{},[363,1793,1794],{},"MSM6",[360,1796,1797],{},"MSM5 data at extended precision",[360,1799,1800],{},"Medium-high",[360,1802,1803,1806],{},[363,1804,1805],{},"Rare"," — not commonly offered by NTRIP services",[339,1808,1809,1814,1817,1819],{},[360,1810,1811],{},[363,1812,1813],{},"1004 \u002F 1012",[360,1815,1816],{},"Legacy GPS + GLONASS observations (pre-MSM)",[360,1818,1743],{},[360,1820,1821,1824],{},[363,1822,1823],{},"Legacy"," — old receivers that do not support MSM",[19,1826,1828],{"id":1827},"msm4-the-universal-default","MSM4 — the universal default",[24,1830,1831],{},"MSM4 contains everything a modern dual-frequency RTK receiver needs to compute a Fix. It includes pseudorange measurements and carrier phase observations for all tracked satellites across all constellations — GPS, GLONASS, Galileo, BeiDou, QZSS. The compressed format keeps bandwidth low, which matters for mobile data connections in the field.",[24,1833,1834],{},"If you are unsure which MSM level to use, start with MSM4. It works correctly with Emlid, u-blox ZED-F9P, Ardusimple and most generic NTRIP clients.",[19,1836,1838],{"id":1837},"msm5-required-for-dji","MSM5 — required for DJI",[24,1840,1841],{},"MSM5 adds Doppler observations to the MSM4 data. DJI's RTK implementation specifically requires Doppler data to initialise correctly. Using MSM4 with a DJI drone will result in Float or no Fix even when the connection appears successful. Always use MSM5 or higher for DJI.",[19,1843,1845],{"id":1844},"msm7-for-professional-survey-equipment","MSM7 — for professional survey equipment",[24,1847,1848],{},"MSM7 provides the same observations as MSM4 but at extended precision — the measurements are stored with more decimal places. For Trimble, Leica and Septentrio receivers that work at sub-centimetre level, MSM7 squeezes out the last bit of accuracy. The bandwidth cost is roughly twice that of MSM4, which is acceptable on modern mobile connections but worth knowing in bandwidth-limited environments.",[207,1850,1852],{"additionalstyles":47,"color":209,"title":1851},"Wrong MSM type causes Float, not an error",[24,1853,1854],{},"If you use MSM4 with a DJI drone, the correction stream flows normally and the connection shows as successful — but the drone stays on Float. There is no error message. The only sign something is wrong is the absence of Fix. If your DJI device never reaches Fix, switching from MSM4 to MSM5 is the first thing to try.",[14,1856,1858],{"id":1857},"which-mountpoint-for-my-device","Which mountpoint for my device?",[24,1860,1861],{},"Select the mountpoint that matches your device and situation.",[219,1863,1864,1868,1872,1876,1880,1884],{"additionalstyles":47},[222,1865],{"text":1866,"title":1867},"Standard survey rover — choose an MSM4 mountpoint. Use VRS when you are more than 30 km from the nearest physical station.","Emlid Reach RS2+, RS3, RS4",[222,1869],{"text":1870,"title":1871},"Network rover only — choose an MSM4 mountpoint. VRS is strongly recommended for long baselines.","Emlid Reach RX \u002F RX2",[222,1873],{"text":1874,"title":1875},"Mavic 3E, M300, M30 RTK — choose MSM5 or higher. DJI requires Doppler observations to reach Fix.","DJI drone",[222,1877],{"text":1878,"title":1879},"Professional survey grade — choose MSM7 to use the extended precision available in high-end receivers.","Trimble \u002F Leica",[222,1881],{"text":1882,"title":1883},"Ardusimple, SparkFun and DIY setups — choose MSM4, the compatible low-bandwidth default.","u-blox ZED-F9P",[222,1885],{"text":1886,"title":1887},"More than 30 km from a station — choose a VRS mountpoint and make sure your NTRIP client sends GGA.","Any device — long baseline",[14,1889,1891],{"id":1890},"reading-a-sourcetable","Reading a sourcetable",[24,1893,1894],{},"When you connect to an NTRIP server without specifying a mountpoint, the server returns a sourcetable — a list of all available correction streams. Understanding how to read it helps you choose the right stream.",[24,1896,1897],{},"A typical sourcetable entry looks like this:",[955,1899],{"additionalstyles":201,"items":1900},"|STR;RTCM3_NL;Netherlands;RTCM 3.3;1004,1006,1008,1012,1019,1020,1033,1042,1045,1046,1077,1087,1097,1107,1127;2;GPS+GLO+GAL+BDS+SBAS;RTKsub;NLD;52.37;4.89;1;1;GEODNET;none;B;N;0;",[24,1902,1903],{},"The key fields to read:",[1905,1906,1907,1914,1920,1926,1932],"ul",{},[1908,1909,1910,1913],"li",{},[363,1911,1912],{},"RTCM3_NL"," — the mountpoint name you enter in your NTRIP client",[1908,1915,1916,1919],{},[363,1917,1918],{},"RTCM 3.3"," — the RTCM version used by this stream",[1908,1921,1922,1925],{},[363,1923,1924],{},"1077, 1087, 1097, 1107, 1127"," — MSM7 message numbers for GPS, GLONASS, Galileo, QZSS and BeiDou. Numbers ending in 4 = MSM4, 5 = MSM5, 7 = MSM7",[1908,1927,1928,1931],{},[363,1929,1930],{},"GPS+GLO+GAL+BDS"," — satellite constellations included in the stream",[1908,1933,1934,1937],{},[363,1935,1936],{},"52.37;4.89"," — approximate latitude and longitude of the reference station",[207,1939,1941],{"additionalstyles":47,"color":205,"title":1940},"You do not need to decode sourcetables manually",[24,1942,1943],{},"Most NTRIP clients have a “Get Mountpoints” button that downloads and displays the sourcetable in a readable format. Use that instead of reading raw entries. The table above is for reference if you ever need to inspect the raw data.",{"title":266,"searchDepth":267,"depth":267,"links":1945},[1946,1947,1948,1953,1954],{"id":1627,"depth":267,"text":1628},{"id":1661,"depth":267,"text":1662},{"id":1699,"depth":267,"text":1700,"children":1949},[1950,1951,1952],{"id":1827,"depth":272,"text":1828},{"id":1837,"depth":272,"text":1838},{"id":1844,"depth":272,"text":1845},{"id":1857,"depth":267,"text":1858},{"id":1890,"depth":267,"text":1891},"learn\u002Fwhat-is-rtcm.webp","RTCM is the universal language that RTK correction services and receivers use to communicate. Choosing the wrong version does not stop corrections from flowing — but choosing the right one gives you faster Fix and better accuracy.",{},"\u002Fen\u002Flearn\u002Fwhat-is-rtcm",[287,602],{"title":1622,"description":1956},"en\u002Flearn\u002Fwhat-is-rtcm","a_cAu34GtgnNoMHTal1dPWChkbkVZLWcgH8uV_0MZBA",{"id":1964,"title":1965,"author":9,"body":1966,"category":278,"cover":2332,"description":2333,"extension":281,"meta":2334,"navigation":283,"path":602,"publishedAt":285,"relatedArticles":2335,"seo":2336,"stem":2337,"updatedAt":4,"__hash__":2338},"knowledge_en\u002Fen\u002Flearn\u002Fwhat-is-vrs.md","What is VRS and when do you need it?",{"type":11,"value":1967,"toc":2323},[1968,1972,1979,1982,1985,2002,2006,2009,2041,2047,2051,2054,2124,2128,2154,2158,2165,2168,2174,2180,2184,2187,2241,2245,2248,2317],[14,1969,1971],{"id":1970},"what-vrs-is-and-why-it-exists","What VRS is and why it exists",[24,1973,1974,1975,1978],{},"VRS stands for ",[363,1976,1977],{},"Virtual Reference Station",". It is a network RTK technology that makes your receiver work as if a physical base station were located just beside you, wherever you are within the correction network's coverage area.",[24,1980,1981],{},"With a normal single-station NTRIP mountpoint, your rover receives corrections from one physical reference station. That station can be 20, 40 or even 60 kilometres away. As the baseline gets longer, the atmospheric conditions at your rover become less like those at the station. Ionospheric and tropospheric errors then make RTK initialisation slower and a Fixed solution less stable.",[24,1983,1984],{},"VRS solves that problem on the server. It combines observations from several surrounding reference stations, models the conditions at your location and sends a synthetic RTCM correction stream. To your receiver, it looks exactly like corrections from a nearby base station.",[309,1986,1987,1991,1995,1999],{"additionalstyles":47},[312,1988],{"text":1989,"title":1990},"Typical effective VRS baseline","1–2 km",[312,1992],{"text":1993,"title":1994},"Reference stations used around you","3+",[312,1996],{"text":1997,"title":1998},"Position message required by VRS","GGA",[312,2000],{"text":2001,"title":1647},"Correction format your rover receives",[14,2003,2005],{"id":2004},"how-vrs-works","How VRS works",[24,2007,2008],{},"VRS is a server-side calculation that runs invisibly behind your NTRIP connection. The sequence is straightforward:",[546,2010,2011,2017,2023,2029,2035],{"additionalstyles":47},[549,2012,2014],{"title":2013},"Connect to a VRS mountpoint",[24,2015,2016],{},"Your NTRIP client connects to the correction service and sends an NMEA GGA sentence with its approximate position. This two-way communication is what makes VRS different from a normal single-station stream.",[549,2018,2020],{"title":2019},"The server places you in the network",[24,2021,2022],{},"The VRS server uses your GGA position to identify the physical reference stations around you. It typically selects three or more nearby stations to build the correction model.",[549,2024,2026],{"title":2025},"Atmospheric conditions are modelled",[24,2027,2028],{},"The server interpolates the ionospheric and tropospheric differences observed across those stations. It estimates the errors that apply at your exact working location.",[549,2030,2032],{"title":2031},"A virtual station is created",[24,2033,2034],{},"The server synthesises an RTCM3 stream as if a base station existed only a kilometre or two from your rover. No physical hardware is installed at that virtual location.",[549,2036,2038],{"title":2037},"Your receiver computes RTK normally",[24,2039,2040],{},"Your receiver processes the VRS corrections like any other RTCM3 stream. It does not need to know whether the corrections came from a real or virtual station; it simply benefits from the short effective baseline.",[207,2042,2044],{"additionalstyles":47,"color":205,"title":2043},"VRS changes the effective baseline, not your equipment",[24,2045,2046],{},"You still use the same rover, field software and NTRIP credentials. Select a VRS mountpoint and transmit GGA; the network does the additional calculation for you.",[14,2048,2050],{"id":2049},"standard-mountpoint-vs-vrs","Standard mountpoint vs VRS",[24,2052,2053],{},"Both options use the same correction network. The important difference is how the correction stream is made.",[45,2055,2059,2072,2085,2098,2111],{"additionalstyles":47,"items":2056,"label":2057,"winner":2058},"Standard mountpoint|VRS mountpoint","Standard NTRIP and VRS comparison","VRS mountpoint",[52,2060,2062,2067],{"title":2061},"Correction source",[56,2063,2064],{"status":64},[24,2065,2066],{},"One physical reference station.",[56,2068,2069],{"status":64},[24,2070,2071],{},"A virtual station calculated from multiple physical stations.",[52,2073,2075,2080],{"title":2074},"Effective baseline",[56,2076,2077],{"status":58},[24,2078,2079],{},"The actual distance to the selected station. It may be tens of kilometres.",[56,2081,2082],{"status":64},[24,2083,2084],{},"Usually around 1–2 km, even when physical stations are far away.",[52,2086,2088,2093],{"title":2087},"GGA transmission",[56,2089,2090],{"status":64},[24,2091,2092],{},"Usually not required.",[56,2094,2095],{"status":58},[24,2096,2097],{},"Required so the server can generate corrections for your location.",[52,2099,2101,2106],{"title":2100},"Working over a large area",[56,2102,2103],{"status":58},[24,2104,2105],{},"You may need to change mountpoints as the nearest station changes.",[56,2107,2108],{"status":64},[24,2109,2110],{},"The network adapts to your position automatically.",[52,2112,2114,2119],{"title":2113},"Fix reliability at long distances",[56,2115,2116],{"status":58},[24,2117,2118],{},"Can degrade as atmospheric differences increase.",[56,2120,2121],{"status":64},[24,2122,2123],{},"Typically faster to initialise and more stable across the network.",[14,2125,2127],{"id":2126},"when-to-use-vrs-and-when-not-to","When to use VRS — and when not to",[219,2129,2130,2134,2138,2142,2146,2150],{"additionalstyles":47},[222,2131],{"text":2132,"title":2133},"Once the nearest physical station is more than roughly 20–30 km away, a VRS stream reduces the baseline-related errors that can keep a receiver in Float or make Fix drop.","Use VRS beyond 20–30 km",[222,2135],{"text":2136,"title":2137},"For work that covers a large area in one day, VRS follows your approximate location. You do not need to keep choosing a different physical station as you travel.","Use VRS when moving across a region",[222,2139],{"text":2140,"title":2141},"If your sky view and connection are good but Fix repeatedly drops on a standard mountpoint, switching to VRS removes baseline length as a likely cause.","Use VRS for unstable Fix",[222,2143],{"text":2144,"title":2145},"High solar activity and geomagnetic disturbances increase ionospheric errors. The network model in a VRS service can compensate for spatial differences much better than a distant single station.","Use VRS during disturbed conditions",[222,2147],{"text":2148,"title":2149},"Within about 15 km of a physical reference station, the atmospheric difference is usually small. A standard mountpoint can work just as well and does not depend on GGA.","A nearby station may be enough",[222,2151],{"text":2152,"title":2153},"The server must receive your GGA position. Without mobile data at the rover, use a local base and radio link or another correction method that works offline.","VRS needs an internet connection",[14,2155,2157],{"id":2156},"the-gga-requirement-explained","The GGA requirement explained",[24,2159,2160,2161,2164],{},"VRS has one requirement that a standard NTRIP connection normally does not: your client must send an ",[363,2162,2163],{},"NMEA GGA sentence"," to the caster. GGA includes latitude, longitude, altitude and fix quality. The server uses it to decide which part of its atmospheric model applies to you and where to place the virtual reference station.",[24,2166,2167],{},"The position does not need to be centimetre accurate. A Single or Float position is enough to locate you in the correct network area. However, the GGA must contain a valid position before you connect.",[207,2169,2171],{"additionalstyles":47,"color":209,"title":2170},"Connected, but receiving 0 bytes per second? Check GGA first.",[24,2172,2173],{},"When GGA is disabled, a connection to a VRS mountpoint can look successful but the caster may send no correction data. Your receiver stays on Single and there may be no obvious error message. Enable GGA transmission, then reconnect.",[207,2175,2177],{"additionalstyles":201,"color":205,"title":2176},"Wait for a valid initial position",[24,2178,2179],{},"Before connecting, give the receiver 30–60 seconds outdoors to obtain satellite lock. A GGA sentence with zero coordinates can be rejected by the server or place the virtual station in the wrong area.",[14,2181,2183],{"id":2182},"how-to-enable-vrs-on-your-device","How to enable VRS on your device",[24,2185,2186],{},"Select the VRS mountpoint supplied by your correction provider, then make sure GGA transmission is enabled. The wording differs slightly by application.",[1231,2188,2190,2200,2208,2218,2226,2234],{"additionalstyles":47,"items":2189},"Emlid Flow|Trimble Access|SW Maps|FieldGenius|DJI Pilot|Lefebure NTRIP",[1235,2191,2192],{"name":1237},[24,2193,1254,2194,2196,2197,2199],{},[363,2195,1243],{},". Select your provider's VRS mountpoint, enable ",[363,2198,1247],{},", then connect after the receiver has a Single solution.",[1235,2201,2202],{"name":1274},[24,2203,2204,2205,2207],{},"Open ",[363,2206,1280],{},", then enter the VRS mountpoint in the NTRIP settings. Trimble Access normally sends GGA automatically while NTRIP is active.",[1235,2209,2210],{"name":1251},[24,2211,1254,2212,2214,2215,2217],{},[363,2213,1257],{},", choose the VRS mountpoint from the sourcetable and enable ",[363,2216,1261],{}," before tapping Connect.",[1235,2219,2220],{"name":1265},[24,2221,2222,2223,2225],{},"Choose ",[363,2224,1270],{},", add a source with the VRS mountpoint and enable GGA transmission in the data-link settings. Confirm the antenna height, then connect.",[1235,2227,2229],{"name":2228},"DJI Pilot",[24,2230,1240,2231,2233],{},[363,2232,1290],{},", enter the VRS mountpoint provided by your service. DJI sends GGA automatically after it has GPS lock, so configure it outdoors.",[1235,2235,2236],{"name":1294},[24,2237,1297,2238,2240],{},[363,2239,1300],{}," in the app settings and select your receiver or the phone's internal GPS as the GGA source.",[14,2242,2244],{"id":2243},"vrs-by-another-name","VRS by another name",[24,2246,2247],{},"VRS is the most common name for network RTK, but it is not the only approach. A sourcetable may also contain these alternatives:",[333,2249,2250,2263],{},[336,2251,2252],{},[339,2253,2254,2257,2260],{},[342,2255,2256],{},"Name",[342,2258,2259],{},"What it does",[342,2261,2262],{},"What you need to know",[355,2264,2265,2278,2291,2304],{},[339,2266,2267,2272,2275],{},[360,2268,2269],{},[363,2270,2271],{},"MAC",[360,2273,2274],{},"The caster sends observations from a master station and auxiliary stations; the receiver performs the network calculation.",[360,2276,2277],{},"Common with Leica systems. GGA is not always required.",[339,2279,2280,2285,2288],{},[360,2281,2282],{},[363,2283,2284],{},"FKP",[360,2286,2287],{},"The caster sends area-correction parameters that the receiver applies to a single-station stream.",[360,2289,2290],{},"An older network format that is less common today.",[339,2292,2293,2298,2301],{},[360,2294,2295],{},[363,2296,2297],{},"iMAX",[360,2299,2300],{},"A personalised version of the Master-Auxiliary approach.",[360,2302,2303],{},"Functionally similar to VRS for most users.",[339,2305,2306,2311,2314],{},[360,2307,2308],{},[363,2309,2310],{},"SSR \u002F SSRZ",[360,2312,2313],{},"Separately models satellite orbits, clocks and atmospheric effects.",[360,2315,2316],{},"A newer approach that is becoming more common in modern networks.",[207,2318,2320],{"additionalstyles":47,"color":260,"title":2319},"For most users, choose the VRS mountpoint",[24,2321,2322],{},"Unless your receiver or correction provider specifically asks for MAC, FKP or another format, VRS is the practical default. It works with modern RTK receivers and gives you near-local network corrections throughout the covered area.",{"title":266,"searchDepth":267,"depth":267,"links":2324},[2325,2326,2327,2328,2329,2330,2331],{"id":1970,"depth":267,"text":1971},{"id":2004,"depth":267,"text":2005},{"id":2049,"depth":267,"text":2050},{"id":2126,"depth":267,"text":2127},{"id":2156,"depth":267,"text":2157},{"id":2182,"depth":267,"text":2183},{"id":2243,"depth":267,"text":2244},"learn\u002Fwhat-is-vrs.webp","VRS (Virtual Reference Station) makes a correction network behave as though a base station is right beside your rover. It eliminates long-baseline errors, improves Fix reliability across a network and is simple to use once GGA transmission is enabled.",{},[287,1616],{"title":1965,"description":2333},"en\u002Flearn\u002Fwhat-is-vrs","Q_R7dGN8SakA5nbtnxs_dK8uAMrv0Wf41kDVzWa369Y",{"id":2340,"title":2341,"author":9,"body":2342,"category":278,"cover":2650,"description":2651,"extension":281,"meta":2652,"navigation":283,"path":2653,"publishedAt":285,"relatedArticles":2654,"seo":2655,"stem":2656,"updatedAt":4,"__hash__":2657},"knowledge_en\u002Fen\u002Flearn\u002Fwhich-mountpoint.md","Which NTRIP mountpoint should I choose?",{"type":11,"value":2343,"toc":2643},[2344,2348,2351,2369,2373,2376,2394,2398,2498,2507,2511,2514,2593,2601,2605,2616,2627,2637],[14,2345,2347],{"id":2346},"quick-mountpoint-finder","Quick mountpoint finder",[24,2349,2350],{},"Choose by device first, then use VRS whenever the nearest reference station is more than 30 km away or Fix is unstable.",[219,2352,2353,2357,2361,2365],{"additionalstyles":47},[222,2354],{"text":2355,"title":2356},"Use MSM4 for Emlid Reach RS \u002F RX, u-blox ZED-F9P, SW Maps, FieldGenius and most generic NTRIP clients.","Most devices within 30 km → RTCM3_NL",[222,2358],{"text":2359,"title":2360},"DJI requires MSM5 Doppler observations to initialise Fix. Do not use the MSM4 default mountpoint for DJI.","Any DJI RTK drone → RTCM3_NL_MSM5",[222,2362],{"text":2363,"title":2364},"MSM7 supplies extended-precision observations that high-end survey receivers can use.","Trimble, Leica or high-end survey → RTCM3_NL_MSM7",[222,2366],{"text":2367,"title":2368},"VRS shortens the effective baseline to 1–2 km. Enable GGA transmission before connecting.","Any device beyond 30 km → RTCM3_NL_VRS",[14,2370,2372],{"id":2371},"all-mountpoints-explained","All mountpoints explained",[24,2374,2375],{},"RTKsub exposes four mountpoints. Each is optimised for a different combination of device type and working distance.",[219,2377,2378,2382,2386,2390],{"additionalstyles":47},[222,2379],{"text":2380,"title":2381},"The standard mountpoint. Delivers RTCM3 corrections in MSM4 format — compact, efficient and compatible with virtually every modern RTK receiver. Includes GPS, GLONASS, Galileo and BeiDou on all frequencies. Use it within 30 km when your device is not a DJI drone or a high-end survey receiver.","RTCM3_NL — MSM4",[222,2383],{"text":2384,"title":2385},"MSM5 adds Doppler observations to the standard MSM4 data. DJI's RTK implementation specifically requires Doppler to initialise correctly. Outside DJI, MSM5 is rarely needed because standard devices perform identically on MSM4 and MSM5.","RTCM3_NL_MSM5 — MSM5",[222,2387],{"text":2388,"title":2389},"MSM7 provides the same observations as MSM4 but at full extended precision. Trimble, Leica, Septentrio and NovAtel receivers can use this extra precision, particularly in challenging baselines and environments. It uses roughly twice the bandwidth of MSM4.","RTCM3_NL_MSM7 — MSM7",[222,2391],{"text":2392,"title":2393},"VRS generates a virtual reference station 1–2 km from your rover using data from multiple surrounding physical stations. Fix initialisation is faster and Fix stability is higher. Send GGA to the caster or the stream returns zero bytes.","RTCM3_NL_VRS — VRS MSM4",[14,2395,2397],{"id":2396},"side-by-side-comparison","Side-by-side comparison",[333,2399,2400,2422],{},[336,2401,2402],{},[339,2403,2404,2407,2410,2413,2416,2419],{},[342,2405,2406],{},"Mountpoint",[342,2408,2409],{},"MSM level",[342,2411,2412],{},"GGA required",[342,2414,2415],{},"DJI works",[342,2417,2418],{},"Trimble \u002F Leica best",[342,2420,2421],{},"Use when",[355,2423,2424,2442,2460,2478],{},[339,2425,2426,2430,2432,2435,2437,2439],{},[360,2427,2428],{},[977,2429,1912],{},[360,2431,1737],{},[360,2433,2434],{},"No",[360,2436,2434],{},[360,2438,2434],{},[360,2440,2441],{},"Default for most devices, baseline \u003C30 km",[339,2443,2444,2449,2451,2453,2455,2457],{},[360,2445,2446],{},[977,2447,2448],{},"RTCM3_NL_MSM5",[360,2450,1756],{},[360,2452,2434],{},[360,2454,1113],{},[360,2456,2434],{},[360,2458,2459],{},"DJI drones only",[339,2461,2462,2467,2469,2471,2473,2475],{},[360,2463,2464],{},[977,2465,2466],{},"RTCM3_NL_MSM7",[360,2468,1775],{},[360,2470,2434],{},[360,2472,2434],{},[360,2474,1113],{},[360,2476,2477],{},"Trimble, Leica, high-end survey",[339,2479,2480,2485,2488,2490,2493,2495],{},[360,2481,2482],{},[977,2483,2484],{},"RTCM3_NL_VRS",[360,2486,2487],{},"MSM4 + VRS",[360,2489,1113],{},[360,2491,2492],{},"Yes*",[360,2494,1113],{},[360,2496,2497],{},"Baseline >30 km or Fix instability",[24,2499,2500,2501,2503,2504,2506],{},"*DJI on VRS: use ",[977,2502,2484],{}," for long-baseline DJI work. For short baselines, use ",[977,2505,2448],{},".",[14,2508,2510],{"id":2509},"what-happens-with-the-wrong-mountpoint","What happens with the wrong mountpoint",[24,2512,2513],{},"The consequences of the wrong mountpoint depend on which way you get it wrong. None of them produce an obvious error message — which is why choosing correctly matters.",[333,2515,2516,2529],{},[336,2517,2518],{},[339,2519,2520,2523,2526],{},[342,2521,2522],{},"Situation",[342,2524,2525],{},"Symptom",[342,2527,2528],{},"What is actually happening",[355,2530,2531,2545,2556,2569,2582],{},[339,2532,2533,2539,2542],{},[360,2534,2535,2536,2538],{},"DJI drone on ",[977,2537,1912],{}," (MSM4)",[360,2540,2541],{},"Stuck on Float indefinitely",[360,2543,2544],{},"DJI needs Doppler data (MSM5 minimum). MSM4 corrections flow but Fix never initialises.",[339,2546,2547,2550,2553],{},[360,2548,2549],{},"Any device on VRS without GGA",[360,2551,2552],{},"Connected, 0 bytes\u002Fsec",[360,2554,2555],{},"Server cannot generate a virtual station. The connection appears active but the stream is empty.",[339,2557,2558,2563,2566],{},[360,2559,2560,2561],{},"Emlid on ",[977,2562,2466],{},[360,2564,2565],{},"Works fine — no problem",[360,2567,2568],{},"Emlid ignores the extra precision in MSM7. Slightly higher bandwidth, otherwise identical result.",[339,2570,2571,2576,2579],{},[360,2572,2573,2574,2538],{},"Trimble on ",[977,2575,1912],{},[360,2577,2578],{},"Fix achieved, slightly lower accuracy",[360,2580,2581],{},"Works correctly. Missing the extended precision that MSM7 provides — a marginal difference in most conditions.",[339,2583,2584,2587,2590],{},[360,2585,2586],{},"Any device, wrong region mountpoint",[360,2588,2589],{},"No corrections or very poor Fix",[360,2591,2592],{},"Corrections come from distant stations, so the baseline is huge.",[207,2594,2596],{"additionalstyles":47,"color":209,"title":2595},"The DJI mistake is the most common",[24,2597,2598,2599,2506],{},"The most frequent support question about mountpoints is: “My DJI drone connects fine but never reaches Fix.” The answer is almost always MSM4 instead of MSM5. If you fly DJI, always use ",[977,2600,2448],{},[14,2602,2604],{"id":2603},"finding-mountpoints-in-the-sourcetable","Finding mountpoints in the sourcetable",[24,2606,2607,2608,2611,2612,2615],{},"Every NTRIP server publishes a sourcetable — a list of all available correction streams with metadata. Your NTRIP client usually has a ",[363,2609,2610],{},"Get Mountpoints"," or ",[363,2613,2614],{},"Download Source Table"," button that fetches and displays this list.",[24,2617,2618,2619,2622,2623,2626],{},"If you need to read the raw sourcetable, you can request it from any NTRIP server by connecting to the host address in a browser or with a tool like ",[977,2620,2621],{},"curl",". Each line starting with ",[977,2624,2625],{},"STR;"," is a mountpoint. The fields are semicolon-separated and include the mountpoint name, format, message types and coordinates of the reference station.",[207,2628,2630],{"additionalstyles":47,"color":205,"title":2629},"Sort by distance in Trimble Access",[24,2631,2632,2633,2636],{},"When the sourcetable loads in Trimble Access, tap the sort button and choose ",[363,2634,2635],{},"Distance",". The nearest physical station appears at the top. If the nearest station is more than 30 km away, switch to the VRS mountpoint rather than the top result.",[207,2638,2640],{"additionalstyles":201,"color":260,"title":2639},"Still unsure? Ask the AI.",[24,2641,2642],{},"If you have an unusual device or a situation not covered here, describe your device model, NTRIP client and intended work. You can then get a specific recommendation.",{"title":266,"searchDepth":267,"depth":267,"links":2644},[2645,2646,2647,2648,2649],{"id":2346,"depth":267,"text":2347},{"id":2371,"depth":267,"text":2372},{"id":2396,"depth":267,"text":2397},{"id":2509,"depth":267,"text":2510},{"id":2603,"depth":267,"text":2604},"learn\u002Fwhich-ntrip-mountpoint-should-i-choose.webp","The right mountpoint depends on two things your device and your baseline. Choose the wrong one and you may get Float instead of Fix, or Fix without the accuracy your receiver is capable of.",{},"\u002Fen\u002Flearn\u002Fwhich-mountpoint",[1958,602],{"title":2341,"description":2651},"en\u002Flearn\u002Fwhich-mountpoint","2oy9yd-U6YpNzoth9z555eT4WEjXlUdxBk5m0gbX-Kc",{"id":2659,"title":2660,"author":295,"body":2661,"category":278,"cover":3005,"description":3006,"extension":281,"meta":3007,"navigation":283,"path":1616,"publishedAt":3008,"relatedArticles":3009,"seo":3010,"stem":3011,"updatedAt":4,"__hash__":3012},"knowledge_en\u002Fen\u002Flearn\u002Ffloat-vs-fix.md","What is the difference between Float and Fix?",{"type":11,"value":2662,"toc":2997},[2663,2667,2715,2719,2722,2725,2728,2759,2762,2765,2769,2772,2808,2812,2942,2946,2949,2975,2979,2982,2985,2991],[14,2664,2666],{"id":2665},"float-vs-fix-at-a-glance","Float vs Fix at a glance",[219,2668,2669,2692],{"additionalstyles":47},[207,2670,2672],{"additionalstyles":1670,"color":209,"title":2671},"Float — Accuracy: 10 cm–1 m horizontal",[1905,2673,2674,2677,2680,2683,2686,2689],{},[1908,2675,2676],{},"Corrections received but not fully resolved",[1908,2678,2679],{},"Ambiguities treated as real numbers, not integers",[1908,2681,2682],{},"Position jumps of 10–50 cm are normal",[1908,2684,2685],{},"Never adequate for precision survey",[1908,2687,2688],{},"Often a stepping stone toward Fix",[1908,2690,2691],{},"Can look like Fix on some displays",[207,2693,2695],{"additionalstyles":1670,"color":260,"title":2694},"Fix — Accuracy: 1–3 cm horizontal, 2–5 cm vertical",[1905,2696,2697,2700,2703,2706,2709,2712],{},[1908,2698,2699],{},"Carrier phase ambiguities fully resolved to integers",[1908,2701,2702],{},"Position is stable and repeatable",[1908,2704,2705],{},"Centimetre accuracy maintained at speed",[1908,2707,2708],{},"Required for precision survey and stakeout",[1908,2710,2711],{},"Takes 10–60 seconds in good conditions",[1908,2713,2714],{},"Shown in green on most field software",[14,2716,2718],{"id":2717},"what-makes-fix-different-ambiguity-resolution","What makes Fix different — ambiguity resolution",[24,2720,2721],{},"To understand Float and Fix you need to understand one concept: carrier phase ambiguity. It is the reason RTK can achieve centimetre accuracy at all — and the reason Float cannot.",[24,2723,2724],{},"GNSS receivers measure position in two ways. The simpler method is pseudorange — measuring the travel time of a satellite signal to estimate distance. Pseudorange gives accuracy of 1–3 metres. The more precise method is carrier phase — measuring the phase of the satellite's radio wave at the receiver antenna. The carrier wave has a wavelength of about 19 cm (for GPS L1). By tracking how many whole wavelengths fit between the satellite and the receiver, and precisely measuring the fractional part, the receiver can measure distance to millimetre precision.",[24,2726,2727],{},"The problem: the receiver knows the fractional part of the carrier phase precisely, but it does not know how many whole wavelengths there are between it and the satellite. This unknown integer number is called the carrier phase ambiguity — or simply the integer ambiguity.",[45,2729,2733,2746],{"additionalstyles":47,"items":2730,"label":2731,"winner":2732},"Float|Fix","Float and Fix ambiguity comparison","Fix",[52,2734,2736,2741],{"title":2735},"Carrier phase ambiguity",[56,2737,2738],{"status":58},[24,2739,2740],{},"The integer cycle count is still unknown and treated as a real-valued estimate.",[56,2742,2743],{"status":64},[24,2744,2745],{},"The integer cycle count has been confirmed as a specific whole number.",[52,2747,2749,2754],{"title":2748},"Position accuracy",[56,2750,2751],{"status":58},[24,2752,2753],{},"10 cm–1 m. The fractional phase is measured, but the unresolved cycle count limits accuracy.",[56,2755,2756],{"status":64},[24,2757,2758],{},"Centimetre precision. The resolved cycle count unlocks the precise fractional measurement.",[24,2760,2761],{},"Resolving the integer ambiguity is what RTK does. Using corrections from the reference station — which has its own precisely known position — the rover can cross-check its carrier phase measurements against the reference and mathematically determine the correct integer values. When the receiver is confident it has the right integers for all tracked satellites, it declares RTK Fixed.",[24,2763,2764],{},"Float means the receiver is still working on this. It has an estimate of the integers — good enough to give sub-metre accuracy — but not yet confident enough to fix them to specific integers. Float accuracy depends on how good the estimate is: anywhere from 10 cm to 1 m, with occasional larger jumps.",[14,2766,2768],{"id":2767},"the-full-solution-progression","The full solution progression",[24,2770,2771],{},"When you connect to an NTRIP service and power up in the field, your receiver moves through several solution types before reaching Fix.",[546,2773,2774,2780,2787,2794,2801],{"additionalstyles":47},[549,2775,2777],{"marker":1080,"title":2776},"No fix — Accuracy: none",[24,2778,2779],{},"The receiver has no satellite lock and no valid position. It is still acquiring signals. This usually takes 15–60 seconds after power-on outdoors.",[549,2781,2784],{"marker":2782,"title":2783},"S","Single — Accuracy: 2–5 m",[24,2785,2786],{},"The receiver has satellite lock and a valid position, but no corrections are applied yet. It uses pseudorange only. This is the type of position reported by standard GPS apps on your phone.",[549,2788,2791],{"marker":2789,"title":2790},"D","DGPS \u002F SBAS — Accuracy: 0.3–1 m",[24,2792,2793],{},"Differential corrections are applied, but only to pseudorange measurements. It is better than Single, but not accurate enough for precision work. This can appear briefly when NTRIP corrections first arrive.",[549,2795,2798],{"marker":2796,"title":2797},"FL","Float — Accuracy: 10 cm–1 m",[24,2799,2800],{},"Carrier phase corrections are applied, but integer ambiguities are not yet resolved. The position is significantly better than Single but not precise enough for survey work. Float is often a transitional state lasting 10–60 seconds before Fix.",[549,2802,2805],{"marker":2803,"title":2804},"FX","Fixed — Accuracy: 1–3 cm horizontal, 2–5 cm vertical",[24,2806,2807],{},"Integer ambiguities are resolved and full RTK accuracy is achieved. This is the solution type required for precision survey, stakeout, machine guidance and drone mapping with ground control points.",[14,2809,2811],{"id":2810},"which-solution-is-good-enough-for-what","Which solution is good enough for what",[45,2813,2816,2832,2849,2864,2880,2895,2911,2926],{"additionalstyles":47,"items":2814,"label":2815,"winner":2732},"Single|Float|Fix","Suitable RTK solution per application",[52,2817,2819,2824,2828],{"title":2818},"Rough navigation — Finding a plot or general location",[56,2820,2821],{"status":64},[24,2822,2823],{},"Good enough",[56,2825,2826],{"status":64},[24,2827,2823],{},[56,2829,2830],{"status":64},[24,2831,2823],{},[52,2833,2835,2839,2844],{"title":2834},"Drone mapping — Direct georeferencing without GCPs",[56,2836,2837],{"status":58},[24,2838,2434],{},[56,2840,2841],{"status":58},[24,2842,2843],{},"Marginal",[56,2845,2846],{"status":64},[24,2847,2848],{},"Required",[52,2850,2852,2856,2860],{"title":2851},"GCP collection for drone mapping",[56,2853,2854],{"status":58},[24,2855,2434],{},[56,2857,2858],{"status":58},[24,2859,2434],{},[56,2861,2862],{"status":64},[24,2863,2848],{},[52,2865,2867,2871,2875],{"title":2866},"Precision agriculture — Auto-steer with 2–5 cm row guidance",[56,2868,2869],{"status":58},[24,2870,2434],{},[56,2872,2873],{"status":58},[24,2874,2843],{},[56,2876,2877],{"status":64},[24,2878,2879],{},"Preferred",[52,2881,2883,2887,2891],{"title":2882},"Survey — Topographic surface mapping",[56,2884,2885],{"status":58},[24,2886,2434],{},[56,2888,2889],{"status":58},[24,2890,2434],{},[56,2892,2893],{"status":64},[24,2894,2848],{},[52,2896,2898,2902,2906],{"title":2897},"Survey — Cadastral or legal property boundaries",[56,2899,2900],{"status":58},[24,2901,2434],{},[56,2903,2904],{"status":58},[24,2905,2434],{},[56,2907,2908],{"status":64},[24,2909,2910],{},"Required + verification",[52,2912,2914,2918,2922],{"title":2913},"Stakeout to 1 cm",[56,2915,2916],{"status":58},[24,2917,2434],{},[56,2919,2920],{"status":58},[24,2921,2434],{},[56,2923,2924],{"status":64},[24,2925,2848],{},[52,2927,2929,2933,2938],{"title":2928},"Machine control — Earthworks",[56,2930,2931],{"status":58},[24,2932,2434],{},[56,2934,2935],{"status":64},[24,2936,2937],{},"Sometimes",[56,2939,2940],{"status":64},[24,2941,2848],{},[14,2943,2945],{"id":2944},"how-to-get-from-float-to-fix-faster","How to get from Float to Fix faster",[24,2947,2948],{},"Float is a transitional state. In good conditions it lasts 10–30 seconds. In challenging conditions it can persist indefinitely. These measures help most:",[219,2950,2951,2955,2959,2963,2967,2971],{"additionalstyles":47},[222,2952],{"text":2953,"title":2954},"Ambiguity resolution requires a strong, stable signal from many satellites simultaneously. Even partial canopy cover significantly slows initialisation.","Go outside with a clear sky view",[222,2956],{"text":2957,"title":2958},"The RTK engine converges faster when the antenna is stationary. Once Fixed, you can move normally. Collecting data while still in Float can delay Fix.","Stand still during initialisation",[222,2960],{"text":2961,"title":2962},"Shorter effective baselines make ambiguity resolution faster and more reliable. Beyond 20 km from a physical station, switch to VRS and enable GGA.","Use a VRS mountpoint",[222,2964],{"text":2965,"title":2966},"More satellites provide more measurement redundancy. Adding GLONASS, Galileo and BeiDou can halve Float-to-Fix time compared with GPS-only.","Enable all satellite constellations",[222,2968],{"text":2969,"title":2970},"Verify that bytes per second is non-zero. A dropped and reconnected correction stream resets initialisation and can leave the receiver stuck on Float.","Check the NTRIP connection",[222,2972],{"text":2973,"title":2974},"Above 4, satellite geometry is poor and ambiguity resolution may not converge. Wait for the geometry window to improve, typically within 15–30 minutes.","Check PDOP",[14,2976,2978],{"id":2977},"false-fix-the-hidden-danger","False Fix — the hidden danger",[24,2980,2981],{},"The most dangerous scenario in RTK is a false Fix — the receiver declares Fixed but has resolved the ambiguities to the wrong integers. The position looks centimetre-precise and stable, but it is wrong by one or more carrier wavelengths (19 cm per L1 cycle).",[24,2983,2984],{},"False Fix produces errors of exactly one or more multiples of the carrier wavelength — 19 cm, 38 cm, 57 cm and so on. It is more common at long baselines, in high multipath environments and during solar storms when ionospheric noise is high.",[207,2986,2988],{"additionalstyles":47,"color":209,"title":2987},"How to detect a false Fix",[24,2989,2990],{},"Always verify on a known control point at the start of any precision survey. Set up over a point with published coordinates and compare your measured position with the known values. A discrepancy of exactly around 19 cm, 38 cm or 57 cm in any direction strongly indicates a false Fix. Disconnect, move to open sky, reconnect and re-initialise before continuing.",[207,2992,2994],{"additionalstyles":47,"color":205,"title":2993},"Fix quality indicator — ratio",[24,2995,2996],{},"Many receivers and field software applications report a Fix quality ratio alongside the solution type. A ratio above 3.0 indicates high confidence. A ratio between 1.5 and 3.0 means the Fix is tentative, so verify it on known points. A ratio below 1.5 may indicate that the receiver should not have declared Fix at all.",{"title":266,"searchDepth":267,"depth":267,"links":2998},[2999,3000,3001,3002,3003,3004],{"id":2665,"depth":267,"text":2666},{"id":2717,"depth":267,"text":2718},{"id":2767,"depth":267,"text":2768},{"id":2810,"depth":267,"text":2811},{"id":2944,"depth":267,"text":2945},{"id":2977,"depth":267,"text":2978},"learn\u002Ffloat-vs-fix.webp","Float and Fix are the two RTK solution types. They look similar on a status screen — both show a position with corrections applied — but the accuracy difference between them is enormous. Fix is centimetres. Float is decimetres to metres. Never collect survey data at Float.",{},"2026-07-24",[287],{"title":2660,"description":3006},"en\u002Flearn\u002Ffloat-vs-fix","rVrcpStYIvAqW_8pcTB5DaAOMLXiCzzea9VNPOocA4Y",{"id":3014,"title":3015,"author":295,"body":3016,"category":278,"cover":3320,"description":3321,"extension":281,"meta":3322,"navigation":283,"path":287,"publishedAt":3008,"relatedArticles":4,"seo":3323,"stem":3324,"updatedAt":4,"__hash__":3325},"knowledge_en\u002Fen\u002Flearn\u002Fwhat-is-ntrip.md","What is NTRIP and how does it work?",{"type":11,"value":3017,"toc":3308},[3018,3022,3025,3028,3045,3049,3052,3076,3080,3083,3087,3094,3097,3101,3104,3108,3146,3152,3156,3159,3253,3257,3275,3281,3285,3288,3302],[14,3019,3021],{"id":3020},"what-ntrip-stands-for","What NTRIP stands for",[24,3023,3024],{},"NTRIP stands for Networked Transport of RTCM via Internet Protocol. Unpacking the name tells you exactly what it does: it takes RTCM correction data — the standard format for RTK corrections — and delivers it over the internet using standard HTTP-based communication.",[24,3026,3027],{},"NTRIP was developed by the German Federal Agency for Cartography and Geodesy (BKG) in the early 2000s and became the global standard for internet-based RTK correction delivery. Today it is used by every major correction network, every modern RTK receiver and virtually every field survey software package.",[309,3029,3030,3034,3038,3041],{"additionalstyles":47},[312,3031],{"text":3032,"title":3033},"Standard TCP port","2101",[312,3035],{"text":3036,"title":3037},"Protocol base","HTTP",[312,3039],{"text":3040,"title":1647},"Data format carried",[312,3042],{"text":3043,"title":3044},"Correction latency","\u003C1 s",[14,3046,3048],{"id":3047},"the-three-components","The three components",[24,3050,3051],{},"NTRIP has three distinct roles — caster, server and client — that together form the correction delivery chain. Understanding these helps you configure your equipment correctly and diagnose connection problems.",[3053,3054,3055,3060,3064,3069,3072],"flow-diagram",{"additionalstyles":47},[3056,3057],"flow-card",{"text":3058,"title":3059},"NTRIP Server","Reference station",[3061,3062],"flow-connector",{"text":3063},"RTCM3 over internet",[3056,3065],{"text":3066,"title":3067,":highlighted":3068},"Central hub","NTRIP Caster","true",[3061,3070],{"text":3071},"RTCM3 stream on demand",[3056,3073],{"text":3074,"title":3075},"NTRIP Client","Your device",[19,3077,3079],{"id":3078},"ntrip-server-the-reference-station-side","NTRIP Server — the reference station side",[24,3081,3082],{},"The NTRIP Server is the software running at each physical reference station. It reads the raw GNSS observations from the receiver and pushes them continuously to the caster over the internet. A reference station broadcasts its data to the caster 24 hours a day, typically at 1-second intervals. You never interact with the server directly — it operates invisibly in the background.",[19,3084,3086],{"id":3085},"ntrip-caster-the-central-hub","NTRIP Caster — the central hub",[24,3088,3089,3090,3093],{},"The NTRIP Caster is the server infrastructure that receives data from all reference stations and distributes it to clients on request. It maintains a sourcetable — a list of all available correction streams (mountpoints) — and authenticates connecting clients. When you enter an NTRIP host address like ",[977,3091,3092],{},"ntrip.rtksub.com",", you are connecting to a caster.",[24,3095,3096],{},"A caster can serve thousands of clients simultaneously from the same set of reference stations. This is why network correction services are economically viable — one physical infrastructure serves many subscribers.",[19,3098,3100],{"id":3099},"ntrip-client-your-device","NTRIP Client — your device",[24,3102,3103],{},"The NTRIP Client is the software on your side — built into Emlid Flow, SW Maps, Trimble Access, FieldGenius and every other modern field application. It connects to the caster, authenticates, selects a mountpoint and receives the correction stream. The client passes the incoming RTCM3 data to the receiver, which uses it to compute an RTK Fix.",[14,3105,3107],{"id":3106},"how-ntrip-works-step-by-step","How NTRIP works step by step",[546,3109,3110,3116,3122,3128,3134,3140],{"additionalstyles":47},[549,3111,3113],{"title":3112},"Reference stations observe satellites",[24,3114,3115],{},"Permanent GNSS receivers at fixed, precisely surveyed locations track all visible satellites continuously. They measure the difference between what the signals should look like at their known position and what they actually receive — this difference is the correction data.",[549,3117,3119],{"title":3118},"Stations stream RTCM3 to the caster",[24,3120,3121],{},"Each reference station sends its correction data to the NTRIP caster in real time. The data is formatted as RTCM3 messages — the universal standard for RTK corrections. This stream flows continuously, every second of every day.",[549,3123,3125],{"title":3124},"Your client connects and authenticates",[24,3126,3127],{},"Your field software (the NTRIP client) opens a TCP connection to the caster on port 2101. It sends an HTTP GET request including your username and password. The caster verifies your credentials and confirms the connection.",[549,3129,3131],{"title":3130},"You select a mountpoint",[24,3132,3133],{},"The caster sends back a sourcetable listing all available correction streams. You select a mountpoint — the name of the specific correction stream you want. Your client sends the mountpoint name back to the caster, which begins streaming that correction data to you.",[549,3135,3137],{"title":3136},"Corrections flow to your receiver",[24,3138,3139],{},"The caster streams RTCM3 correction messages continuously to your client. Your field software or NTRIP app passes these to your GNSS receiver — typically via Bluetooth, USB or directly over the network if the receiver has its own IP connection.",[549,3141,3143],{"title":3142},"Your receiver computes RTK Fixed",[24,3144,3145],{},"The receiver combines the incoming corrections with its own satellite observations. It resolves carrier phase ambiguities — the mathematical step that unlocks centimetre accuracy — and outputs an RTK Fixed position. In good conditions this takes 10–60 seconds from the moment corrections begin flowing.",[207,3147,3149],{"additionalstyles":47,"color":205,"title":3148},"NTRIP is essentially streaming audio — but for position",[24,3150,3151],{},"A useful analogy: NTRIP works like an internet radio stream. The caster is the radio server. Your NTRIP client is the app on your phone. The mountpoint is the station you tune to. Corrections flow continuously as long as you are connected — and like a radio stream, a brief internet dropout interrupts it until the connection re-establishes.",[14,3153,3155],{"id":3154},"ntrip-vs-radio-link","NTRIP vs radio link",[24,3157,3158],{},"Before NTRIP became widespread, RTK corrections were delivered by UHF radio — a base station on site broadcast corrections to rovers within line-of-sight range. Radio is still used today, but NTRIP has become the dominant method for most professional applications.",[45,3160,3164,3177,3190,3202,3215,3228,3240],{"additionalstyles":47,"items":3161,"label":3162,"winner":3163},"UHF radio link|NTRIP","UHF radio link compared with NTRIP","NTRIP",[52,3165,3167,3172],{"title":3166},"Range",[56,3168,3169],{"status":58},[24,3170,3171],{},"2–10 km line of sight. Terrain and buildings block signal.",[56,3173,3174],{"status":64},[24,3175,3176],{},"Unlimited within network coverage. Works across an entire country.",[52,3178,3180,3185],{"title":3179},"Infrastructure required",[56,3181,3182],{"status":58},[24,3183,3184],{},"Base station, tripod, radio module, battery. 15–30 min setup per job.",[56,3186,3187],{"status":64},[24,3188,3189],{},"One rover. Mobile data connection. No base station.",[52,3191,3192,3197],{"title":109},[56,3193,3194],{"status":64},[24,3195,3196],{},"Yes — fully independent of internet or mobile coverage.",[56,3198,3199],{"status":58},[24,3200,3201],{},"No — requires mobile data at the rover location.",[52,3203,3205,3210],{"title":3204},"Latency",[56,3206,3207],{"status":64},[24,3208,3209],{},"\u003C100 ms — very low latency, ideal for machine guidance.",[56,3211,3212],{"status":64},[24,3213,3214],{},"\u003C1 s over 4G — acceptable for all surveying applications.",[52,3216,3218,3223],{"title":3217},"Number of rovers served",[56,3219,3220],{"status":58},[24,3221,3222],{},"Unlimited — radio broadcast reaches all rovers in range.",[56,3224,3225],{"status":58},[24,3226,3227],{},"Each rover needs its own NTRIP connection and subscription.",[52,3229,3230,3235],{"title":96},[56,3231,3232],{"status":58},[24,3233,3234],{},"Best within 10 km of base. Degrades at distance.",[56,3236,3237],{"status":64},[24,3238,3239],{},"Consistent with VRS across the entire network coverage area.",[52,3241,3243,3248],{"title":3242},"Cost",[56,3244,3245],{"status":58},[24,3246,3247],{},"High upfront hardware cost. No ongoing fees.",[56,3249,3250],{"status":64},[24,3251,3252],{},"Low upfront (one receiver). Monthly subscription for corrections.",[14,3254,3256],{"id":3255},"what-you-need-to-use-ntrip","What you need to use NTRIP",[219,3258,3259,3263,3267,3271],{"additionalstyles":47},[222,3260],{"text":3261,"title":3262},"Any modern multi-band RTK receiver. Emlid, Trimble, Leica, u-blox ZED-F9P and most others support NTRIP natively.","NTRIP-compatible receiver",[222,3264],{"text":3265,"title":3266},"Built into Emlid Flow, SW Maps, Trimble Access, FieldGenius, Lefebure and most field apps. You are unlikely to need a separate client.","NTRIP client software",[222,3268],{"text":3269,"title":3270},"Mobile data (4G or 3G) at the rover location. A few hundred kilobytes per hour — similar to a basic messaging app.","Internet connection",[222,3272],{"text":3273,"title":3274},"Host address, port (2101), mountpoint name, username and password from your correction service provider.","NTRIP credentials",[207,3276,3278],{"additionalstyles":47,"color":260,"title":3277},"NTRIP data usage is very low",[24,3279,3280],{},"A typical NTRIP correction stream uses 50–200 KB per hour depending on the mountpoint and number of satellite constellations. Over a full 8-hour working day this is under 2 MB — negligible on any mobile data plan. NTRIP will not meaningfully affect your data allowance.",[14,3282,3284],{"id":3283},"ntrip-v1-vs-ntrip-v2","NTRIP v1 vs NTRIP v2",[24,3286,3287],{},"There are two versions of the NTRIP standard. Most users will never need to think about this distinction — your software handles it automatically — but it is useful to understand when troubleshooting.",[1905,3289,3290,3296],{},[1908,3291,3292,3295],{},[363,3293,3294],{},"NTRIP v1"," (2004) — the original standard. Uses basic HTTP 1.0. One-way communication: the caster sends corrections and receives nothing back from the client. Does not natively support GGA position transmission for VRS. Still widely supported by all servers and clients.",[1908,3297,3298,3301],{},[363,3299,3300],{},"NTRIP v2"," (2007) — adds bidirectional communication over HTTP 1.1. Supports GGA transmission from client to caster within the protocol — this is how VRS mountpoints work. Supports chunked transfer encoding for more reliable streaming. Trimble Access automatically negotiates v2 if the server supports it.",[207,3303,3305],{"additionalstyles":47,"color":209,"title":3304},"Force v1 only if you have connection problems",[24,3306,3307],{},"Some older equipment or network configurations have problems with NTRIP v2 negotiation. If you cannot connect and everything else looks correct, try forcing your client to use NTRIP v1.0. In Trimble Access this is a checkbox in the survey style data link settings. In most other clients, look for an \"NTRIP version\" dropdown.",{"title":266,"searchDepth":267,"depth":267,"links":3309},[3310,3311,3316,3317,3318,3319],{"id":3020,"depth":267,"text":3021},{"id":3047,"depth":267,"text":3048,"children":3312},[3313,3314,3315],{"id":3078,"depth":272,"text":3079},{"id":3085,"depth":272,"text":3086},{"id":3099,"depth":272,"text":3100},{"id":3106,"depth":267,"text":3107},{"id":3154,"depth":267,"text":3155},{"id":3255,"depth":267,"text":3256},{"id":3283,"depth":267,"text":3284},"learn\u002Fwhat-is-ntrip.webp","NTRIP is the internet protocol that delivers RTK correction data from reference stations to your rover over a mobile data connection. It replaced radio links as the dominant correction delivery method — and it is the reason a single receiver with a SIM card can achieve centimetre accuracy anywhere in a correction network's coverage area.",{},{"title":3015,"description":3321},"en\u002Flearn\u002Fwhat-is-ntrip","zwxVSM1r0uMgUoqabd-awIyiWlIAORHYhZCmNiesBK0",[],1787304609807]