[{"data":1,"prerenderedAt":1111},["ShallowReactive",2],{"knowledge-page-en-\u002Flearn\u002Fwhat-is-pdop":3},{"article":4,"posts":318,"relatedPosts":319},{"id":5,"title":6,"author":7,"body":8,"category":303,"cover":304,"description":305,"extension":306,"meta":307,"navigation":308,"path":309,"publishedAt":310,"relatedArticles":311,"seo":314,"stem":315,"updatedAt":316,"__hash__":317},"knowledge_en\u002Fen\u002Flearn\u002Fwhat-is-pdop.md","What is PDOP and why does it matter for RTK?","Yuri",{"type":9,"value":10,"toc":293},"minimark",[11,16,25,28,49,53,56,64,113,117,190,198,202,222,226,265,269,272,286],[12,13,15],"h2",{"id":14},"what-pdop-means","What PDOP means",[17,18,19,20,24],"p",{},"PDOP stands for ",[21,22,23],"strong",{},"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.",[17,26,27],{},"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.",[29,30,32,37,41,45],"text-grid",{"additionalstyles":31},"mt-[60px]",[33,34],"text-grid-item",{"text":35,"title":36},"Excellent satellite geometry","\u003C 2",[33,38],{"text":39,"title":40},"Good for normal RTK work","2–4",[33,42],{"text":43,"title":44},"Use extra care and verify","4–6",[33,46],{"text":47,"title":48},"Poor geometry — wait if possible","> 6",[12,50,52],{"id":51},"why-satellite-geometry-matters","Why satellite geometry matters",[17,54,55],{},"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.",[17,57,58,59,63],{},"GNSS works the same way. Your receiver needs signals from several satellites, but the ",[60,61,62],"em",{},"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.",[65,66,70,87,100],"compare-table",{"additionalstyles":31,"items":67,"label":68,"winner":69},"Low PDOP|High PDOP","Low and high PDOP comparison","Low PDOP",[71,72,74,81],"compare-row",{"title":73},"Satellite pattern",[75,76,78],"compare-cell",{"status":77},"positive",[17,79,80],{},"Satellites are spread widely across the sky and at different elevations.",[75,82,84],{"status":83},"negative",[17,85,86],{},"Satellites are clustered in one direction or blocked by the environment.",[71,88,90,95],{"title":89},"Position confidence",[75,91,92],{"status":77},[17,93,94],{},"Small measurement errors have a limited effect on the final position.",[75,96,97],{"status":83},[17,98,99],{},"Small measurement errors can produce a much larger position error.",[71,101,103,108],{"title":102},"RTK behaviour",[75,104,105],{"status":77},[17,106,107],{},"Fix initialisation is usually faster and more reliable.",[75,109,110],{"status":83},[17,111,112],{},"Fix can take longer, drop to Float or fail to initialise.",[12,114,116],{"id":115},"pdop-ranges-in-practice","PDOP ranges in practice",[118,119,120,136],"table",{},[121,122,123],"thead",{},[124,125,126,130,133],"tr",{},[127,128,129],"th",{},"PDOP",[127,131,132],{},"Meaning",[127,134,135],{},"What to do",[137,138,139,153,165,177],"tbody",{},[124,140,141,147,150],{},[142,143,144],"td",{},[21,145,146],{},"Below 2",[142,148,149],{},"Excellent geometry",[142,151,152],{},"Ideal for survey, stakeout and control measurements.",[124,154,155,159,162],{},[142,156,157],{},[21,158,40],{},[142,160,161],{},"Good geometry",[142,163,164],{},"Suitable for normal RTK work.",[124,166,167,171,174],{},[142,168,169],{},[21,170,44],{},[142,172,173],{},"Marginal geometry",[142,175,176],{},"Check your result on a known point and avoid critical measurements if you can wait.",[124,178,179,184,187],{},[142,180,181],{},[21,182,183],{},"Above 6",[142,185,186],{},"Poor geometry",[142,188,189],{},"Wait for the satellite pattern to improve, or move to a clearer location.",[191,192,195],"card",{"additionalstyles":31,"color":193,"title":194},"primary","PDOP is not an accuracy value",[17,196,197],{},"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.",[12,199,201],{"id":200},"what-causes-high-pdop","What causes high PDOP?",[203,204,205,210,214,218],"cards",{"additionalstyles":31},[206,207],"cards-item",{"text":208,"title":209},"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",[206,211],{"text":212,"title":213},"Satellite positions change continuously. A poor geometry window at 10:00 can become excellent 30 minutes later without you changing anything.","Time of day",[206,215],{"text":216,"title":217},"GPS-only tracking gives the receiver fewer geometry options. Enable GLONASS, Galileo and BeiDou when your receiver and correction stream support them.","Limited constellations",[206,219],{"text":220,"title":221},"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",[12,223,225],{"id":224},"how-to-improve-pdop-in-the-field","How to improve PDOP in the field",[227,228,229,237,244,251,258],"stepper",{"additionalstyles":31},[230,231,234],"stepper-item",{"marker":232,"title":233},"1","Move to a clearer sky view",[17,235,236],{},"Step away from walls, machinery, tree canopies and building overhangs. Even a few metres can reveal satellites that were previously blocked.",[230,238,241],{"marker":239,"title":240},"2","Enable every available constellation",[17,242,243],{},"Use GPS, GLONASS, Galileo and BeiDou where possible. More constellations give the receiver more satellites to form a good geometry pattern.",[230,245,248],{"marker":246,"title":247},"3","Wait for the geometry window",[17,249,250],{},"If PDOP remains high in open sky, wait 15–30 minutes and check again. The satellite configuration changes naturally throughout the day.",[230,252,255],{"marker":253,"title":254},"4","Review your elevation mask",[17,256,257],{},"In open sky, an elevation mask around 10–15° is a practical starting point. Raising it too far can unnecessarily remove useful satellites.",[230,259,262],{"marker":260,"title":261},"5","Verify critical work on known control",[17,263,264],{},"When PDOP is marginal, check a known point before collecting high-consequence measurements. A Fixed status alone is not a substitute for verification.",[12,266,268],{"id":267},"pdop-hdop-and-vdop","PDOP, HDOP and VDOP",[17,270,271],{},"PDOP is the combined three-dimensional geometry value. You may also see two related values in your receiver status screen:",[203,273,274,278,282],{"additionalstyles":31},[206,275],{"text":276,"title":277},"Describes the geometry for latitude and longitude. It matters most for mapping, stakeout and horizontal control.","HDOP — Horizontal Dilution of Precision",[206,279],{"text":280,"title":281},"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",[206,283],{"text":284,"title":285},"Combines horizontal and vertical geometry into one overall indicator. It is the value most field applications display by default.","PDOP — Position Dilution of Precision",[191,287,290],{"additionalstyles":31,"color":288,"title":289},"green","A practical rule: do not chase a perfect number",[17,291,292],{},"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":294,"searchDepth":295,"depth":295,"links":296},"",2,[297,298,299,300,301,302],{"id":14,"depth":295,"text":15},{"id":51,"depth":295,"text":52},{"id":115,"depth":295,"text":116},{"id":200,"depth":295,"text":201},{"id":224,"depth":295,"text":225},{"id":267,"depth":295,"text":268},"learn","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.","md",{},true,"\u002Fen\u002Flearn\u002Fwhat-is-pdop","2026-07-25",[312,313],"\u002Fen\u002Flearn\u002Ffloat-vs-fix","\u002Fen\u002Flearn\u002Fwhat-is-gga",{"title":6,"description":305},"en\u002Flearn\u002Fwhat-is-pdop",null,"5c162tbZmsNiSXL_1NVOC59NXuH-qpiRg5RQ8G8jwBU",[],[320,683],{"id":321,"title":322,"author":323,"body":324,"category":303,"cover":674,"description":675,"extension":306,"meta":676,"navigation":308,"path":312,"publishedAt":677,"relatedArticles":678,"seo":680,"stem":681,"updatedAt":316,"__hash__":682},"knowledge_en\u002Fen\u002Flearn\u002Ffloat-vs-fix.md","What is the difference between Float and Fix?","Wilko",{"type":9,"value":325,"toc":666},[326,330,382,386,389,392,395,426,429,432,436,439,476,480,611,615,618,644,648,651,654,660],[12,327,329],{"id":328},"float-vs-fix-at-a-glance","Float vs Fix at a glance",[203,331,332,359],{"additionalstyles":31},[191,333,337],{"additionalstyles":334,"color":335,"title":336},"h-full","orange","Float — Accuracy: 10 cm–1 m horizontal",[338,339,340,344,347,350,353,356],"ul",{},[341,342,343],"li",{},"Corrections received but not fully resolved",[341,345,346],{},"Ambiguities treated as real numbers, not integers",[341,348,349],{},"Position jumps of 10–50 cm are normal",[341,351,352],{},"Never adequate for precision survey",[341,354,355],{},"Often a stepping stone toward Fix",[341,357,358],{},"Can look like Fix on some displays",[191,360,362],{"additionalstyles":334,"color":288,"title":361},"Fix — Accuracy: 1–3 cm horizontal, 2–5 cm vertical",[338,363,364,367,370,373,376,379],{},[341,365,366],{},"Carrier phase ambiguities fully resolved to integers",[341,368,369],{},"Position is stable and repeatable",[341,371,372],{},"Centimetre accuracy maintained at speed",[341,374,375],{},"Required for precision survey and stakeout",[341,377,378],{},"Takes 10–60 seconds in good conditions",[341,380,381],{},"Shown in green on most field software",[12,383,385],{"id":384},"what-makes-fix-different-ambiguity-resolution","What makes Fix different — ambiguity resolution",[17,387,388],{},"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.",[17,390,391],{},"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.",[17,393,394],{},"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.",[65,396,400,413],{"additionalstyles":31,"items":397,"label":398,"winner":399},"Float|Fix","Float and Fix ambiguity comparison","Fix",[71,401,403,408],{"title":402},"Carrier phase ambiguity",[75,404,405],{"status":83},[17,406,407],{},"The integer cycle count is still unknown and treated as a real-valued estimate.",[75,409,410],{"status":77},[17,411,412],{},"The integer cycle count has been confirmed as a specific whole number.",[71,414,416,421],{"title":415},"Position accuracy",[75,417,418],{"status":83},[17,419,420],{},"10 cm–1 m. The fractional phase is measured, but the unresolved cycle count limits accuracy.",[75,422,423],{"status":77},[17,424,425],{},"Centimetre precision. The resolved cycle count unlocks the precise fractional measurement.",[17,427,428],{},"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.",[17,430,431],{},"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.",[12,433,435],{"id":434},"the-full-solution-progression","The full solution progression",[17,437,438],{},"When you connect to an NTRIP service and power up in the field, your receiver moves through several solution types before reaching Fix.",[227,440,441,448,455,462,469],{"additionalstyles":31},[230,442,445],{"marker":443,"title":444},"—","No fix — Accuracy: none",[17,446,447],{},"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.",[230,449,452],{"marker":450,"title":451},"S","Single — Accuracy: 2–5 m",[17,453,454],{},"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.",[230,456,459],{"marker":457,"title":458},"D","DGPS \u002F SBAS — Accuracy: 0.3–1 m",[17,460,461],{},"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.",[230,463,466],{"marker":464,"title":465},"FL","Float — Accuracy: 10 cm–1 m",[17,467,468],{},"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.",[230,470,473],{"marker":471,"title":472},"FX","Fixed — Accuracy: 1–3 cm horizontal, 2–5 cm vertical",[17,474,475],{},"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.",[12,477,479],{"id":478},"which-solution-is-good-enough-for-what","Which solution is good enough for what",[65,481,484,500,518,533,549,564,580,595],{"additionalstyles":31,"items":482,"label":483,"winner":399},"Single|Float|Fix","Suitable RTK solution per application",[71,485,487,492,496],{"title":486},"Rough navigation — Finding a plot or general location",[75,488,489],{"status":77},[17,490,491],{},"Good enough",[75,493,494],{"status":77},[17,495,491],{},[75,497,498],{"status":77},[17,499,491],{},[71,501,503,508,513],{"title":502},"Drone mapping — Direct georeferencing without GCPs",[75,504,505],{"status":83},[17,506,507],{},"No",[75,509,510],{"status":83},[17,511,512],{},"Marginal",[75,514,515],{"status":77},[17,516,517],{},"Required",[71,519,521,525,529],{"title":520},"GCP collection for drone mapping",[75,522,523],{"status":83},[17,524,507],{},[75,526,527],{"status":83},[17,528,507],{},[75,530,531],{"status":77},[17,532,517],{},[71,534,536,540,544],{"title":535},"Precision agriculture — Auto-steer with 2–5 cm row guidance",[75,537,538],{"status":83},[17,539,507],{},[75,541,542],{"status":83},[17,543,512],{},[75,545,546],{"status":77},[17,547,548],{},"Preferred",[71,550,552,556,560],{"title":551},"Survey — Topographic surface mapping",[75,553,554],{"status":83},[17,555,507],{},[75,557,558],{"status":83},[17,559,507],{},[75,561,562],{"status":77},[17,563,517],{},[71,565,567,571,575],{"title":566},"Survey — Cadastral or legal property boundaries",[75,568,569],{"status":83},[17,570,507],{},[75,572,573],{"status":83},[17,574,507],{},[75,576,577],{"status":77},[17,578,579],{},"Required + verification",[71,581,583,587,591],{"title":582},"Stakeout to 1 cm",[75,584,585],{"status":83},[17,586,507],{},[75,588,589],{"status":83},[17,590,507],{},[75,592,593],{"status":77},[17,594,517],{},[71,596,598,602,607],{"title":597},"Machine control — Earthworks",[75,599,600],{"status":83},[17,601,507],{},[75,603,604],{"status":77},[17,605,606],{},"Sometimes",[75,608,609],{"status":77},[17,610,517],{},[12,612,614],{"id":613},"how-to-get-from-float-to-fix-faster","How to get from Float to Fix faster",[17,616,617],{},"Float is a transitional state. In good conditions it lasts 10–30 seconds. In challenging conditions it can persist indefinitely. These measures help most:",[203,619,620,624,628,632,636,640],{"additionalstyles":31},[206,621],{"text":622,"title":623},"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",[206,625],{"text":626,"title":627},"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",[206,629],{"text":630,"title":631},"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",[206,633],{"text":634,"title":635},"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",[206,637],{"text":638,"title":639},"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",[206,641],{"text":642,"title":643},"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",[12,645,647],{"id":646},"false-fix-the-hidden-danger","False Fix — the hidden danger",[17,649,650],{},"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).",[17,652,653],{},"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.",[191,655,657],{"additionalstyles":31,"color":335,"title":656},"How to detect a false Fix",[17,658,659],{},"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.",[191,661,663],{"additionalstyles":31,"color":193,"title":662},"Fix quality indicator — ratio",[17,664,665],{},"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":294,"searchDepth":295,"depth":295,"links":667},[668,669,670,671,672,673],{"id":328,"depth":295,"text":329},{"id":384,"depth":295,"text":385},{"id":434,"depth":295,"text":435},{"id":478,"depth":295,"text":479},{"id":613,"depth":295,"text":614},{"id":646,"depth":295,"text":647},"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",[679],"\u002Fen\u002Flearn\u002Fwhat-is-ntrip",{"title":322,"description":675},"en\u002Flearn\u002Ffloat-vs-fix","rVrcpStYIvAqW_8pcTB5DaAOMLXiCzzea9VNPOocA4Y",{"id":684,"title":685,"author":7,"body":686,"category":303,"cover":1103,"description":1104,"extension":306,"meta":1105,"navigation":308,"path":313,"publishedAt":310,"relatedArticles":1106,"seo":1108,"stem":1109,"updatedAt":316,"__hash__":1110},"knowledge_en\u002Fen\u002Flearn\u002Fwhat-is-gga.md","What is GGA and why do I need to enable it?",{"type":9,"value":687,"toc":1092},[688,692,699,706,709,713,716,721,804,809,812,921,927,931,963,967,985,989,992,1070,1074],[12,689,691],{"id":690},"what-gga-is","What GGA is",[17,693,694,695,698],{},"GGA stands for ",[21,696,697],{},"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.",[17,700,701,702,705],{},"In the context of NTRIP, GGA has a specific role: it is the sentence your device sends ",[60,703,704],{},"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.",[17,707,708],{},"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.",[12,710,712],{"id":711},"what-a-gga-sentence-contains","What a GGA sentence contains",[17,714,715],{},"A typical GGA sentence looks like this. Each comma-separated field carries a specific piece of information:",[717,718],"terminal-box",{"additionalstyles":719,"items":720},"mt-[30px]","Example GGA sentence|$GPGGA,123519,5230.000,N,00452.000,E,4,09,0.9,25.4,M,46.9,M,,*47",[118,722,723,732],{},[121,724,725],{},[124,726,727,730],{},[127,728,729],{},"Field",[127,731,132],{},[137,733,734,745,755,765,774,784,794],{},[124,735,736,742],{},[142,737,738],{},[739,740,741],"code",{},"123519",[142,743,744],{},"UTC time — 12:35:19",[124,746,747,752],{},[142,748,749],{},[739,750,751],{},"5230.000,N",[142,753,754],{},"Latitude — 52° 30.000' North (Netherlands)",[124,756,757,762],{},[142,758,759],{},[739,760,761],{},"00452.000,E",[142,763,764],{},"Longitude — 4° 52.000' East",[124,766,767,771],{},[142,768,769],{},[739,770,253],{},[142,772,773],{},"Fix quality — 4 = RTK Fixed (see table below)",[124,775,776,781],{},[142,777,778],{},[739,779,780],{},"09",[142,782,783],{},"Number of satellites in use",[124,785,786,791],{},[142,787,788],{},[739,789,790],{},"0.9",[142,792,793],{},"HDOP — horizontal dilution of precision",[124,795,796,801],{},[142,797,798],{},[739,799,800],{},"25.4,M",[142,802,803],{},"Altitude above mean sea level in metres",[805,806,808],"h3",{"id":807},"fix-quality-values","Fix quality values",[17,810,811],{},"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:",[118,813,814,829],{},[121,815,816],{},[124,817,818,821,823,826],{},[127,819,820],{},"Value",[127,822,132],{},[127,824,825],{},"Typical accuracy",[127,827,828],{},"Suitable for VRS?",[137,830,831,846,861,876,891,905],{},[124,832,833,838,841,843],{},[142,834,835],{},[739,836,837],{},"0",[142,839,840],{},"No fix",[142,842,443],{},[142,844,845],{},"No — position is invalid",[124,847,848,852,855,858],{},[142,849,850],{},[739,851,232],{},[142,853,854],{},"GPS fix (Single)",[142,856,857],{},"2–5 m",[142,859,860],{},"Yes — good enough to locate in network",[124,862,863,867,870,873],{},[142,864,865],{},[739,866,239],{},[142,868,869],{},"DGPS fix",[142,871,872],{},"0.5–2 m",[142,874,875],{},"Yes",[124,877,878,882,885,888],{},[142,879,880],{},[739,881,253],{},[142,883,884],{},"RTK Fixed",[142,886,887],{},"1–3 cm",[142,889,890],{},"Yes — best quality GGA",[124,892,893,897,900,903],{},[142,894,895],{},[739,896,260],{},[142,898,899],{},"RTK Float",[142,901,902],{},"0.1–1 m",[142,904,875],{},[124,906,907,912,915,918],{},[142,908,909],{},[739,910,911],{},"6",[142,913,914],{},"Dead reckoning",[142,916,917],{},"Variable",[142,919,920],{},"Depends on accuracy",[191,922,924],{"additionalstyles":31,"color":193,"title":923},"You do not need Fix before sending GGA",[17,925,926],{},"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.",[12,928,930],{"id":929},"how-gga-enables-vrs","How GGA enables VRS",[227,932,933,939,945,951,957],{"additionalstyles":31},[230,934,936],{"marker":232,"title":935},"Your receiver gets a rough position",[17,937,938],{},"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.",[230,940,942],{"marker":239,"title":941},"Your NTRIP client sends GGA to the server",[17,943,944],{},"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.",[230,946,948],{"marker":246,"title":947},"The server identifies your location in the network",[17,949,950],{},"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.",[230,952,954],{"marker":253,"title":953},"A virtual station is generated near you",[17,955,956],{},"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.",[230,958,960],{"marker":260,"title":959},"Your receiver achieves RTK Fixed",[17,961,962],{},"With local-quality corrections flowing, your receiver resolves carrier phase ambiguities and reaches Fixed — typically within 10–60 seconds in good sky conditions.",[12,964,966],{"id":965},"when-gga-is-required-vs-optional","When GGA is required vs optional",[203,968,969,973,977,981],{"additionalstyles":31},[206,970],{"text":971,"title":972},"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",[206,974],{"text":975,"title":976},"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",[206,978],{"text":979,"title":980},"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",[206,982],{"text":983,"title":984},"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",[12,986,988],{"id":987},"how-to-enable-gga-on-your-device","How to enable GGA on your device",[17,990,991],{},"The setting name varies between NTRIP clients, but the function is the same on all of them.",[993,994,996,1011,1025,1034,1044,1054,1064],"device-tabs",{"additionalstyles":31,"items":995},"Emlid Flow|SW Maps|FieldGenius|Trimble Access|DJI Pilot 2|Lefebure NTRIP|Leica Captivate",[997,998,1000],"device-tab",{"name":999},"Emlid Flow",[17,1001,1002,1003,1006,1007,1010],{},"In ",[21,1004,1005],{},"Correction input → NTRIP",", select your VRS mountpoint and enable ",[21,1008,1009],{},"Send GGA to caster",". Connect after the receiver has a valid Single solution.",[997,1012,1014],{"name":1013},"SW Maps",[17,1015,1016,1017,1020,1021,1024],{},"Go to ",[21,1018,1019],{},"Settings → NTRIP Client",", select the VRS mountpoint and enable ",[21,1022,1023],{},"Transmit GGA"," before connecting.",[997,1026,1028],{"name":1027},"FieldGenius",[17,1029,1016,1030,1033],{},[21,1031,1032],{},"Set Up Corrections → RTK via Internet",". Select the VRS source and enable GGA transmission in the data-link settings.",[997,1035,1037],{"name":1036},"Trimble Access",[17,1038,1039,1040,1043],{},"Enter the VRS mountpoint in ",[21,1041,1042],{},"Survey Style → Rover radio",". Trimble Access sends GGA automatically while NTRIP is active.",[997,1045,1047],{"name":1046},"DJI Pilot 2",[17,1048,1049,1050,1053],{},"Enter the VRS mountpoint under ",[21,1051,1052],{},"RTK Settings → Custom Network RTK",". DJI sends GGA automatically after it has GPS lock, so configure it outdoors.",[997,1055,1057],{"name":1056},"Lefebure NTRIP",[17,1058,1059,1060,1063],{},"Enter the caster host, port and VRS mountpoint. Enable ",[21,1061,1062],{},"Send GGA"," and select the receiver or internal GPS as the GGA source.",[997,1065,1067],{"name":1066},"Leica Captivate",[17,1068,1069],{},"In the internet connection or rover settings, select the VRS mountpoint and enable NMEA GGA output to the NTRIP caster.",[12,1071,1073],{"id":1072},"gga-troubleshooting","GGA troubleshooting",[203,1075,1076,1080,1084,1088],{"additionalstyles":31},[206,1077],{"text":1078,"title":1079},"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",[206,1081],{"text":1082,"title":1083},"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",[206,1085],{"text":1086,"title":1087},"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?",[206,1089],{"text":1090,"title":1091},"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":294,"searchDepth":295,"depth":295,"links":1093},[1094,1095,1099,1100,1101,1102],{"id":690,"depth":295,"text":691},{"id":711,"depth":295,"text":712,"children":1096},[1097],{"id":807,"depth":1098,"text":808},3,{"id":929,"depth":295,"text":930},{"id":965,"depth":295,"text":966},{"id":987,"depth":295,"text":988},{"id":1072,"depth":295,"text":1073},"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.",{},[1107,679],"\u002Fen\u002Flearn\u002Fwhat-is-vrs",{"title":685,"description":1104},"en\u002Flearn\u002Fwhat-is-gga","HFG0RJGp9bO8FHQR5HkzNRVEiSqOCSmiRVEfH3EUQ58",1787304715637]