Article — GNSS basics
DGPS Full Form, Meaning and How a DGPS Survey Works
Differential GPS explained in plain words: the two receivers, the errors they cancel, and what that means for your plot or route.
Quick AnswerThe DGPS full form is Differential Global Positioning System. One receiver, the base, sits on a point of known position and works out how far its satellite fix wanders. That correction then goes to a second, roving receiver close by, whose position improves from a few metres to 1–2 cm. To decide when you need a DGPS survey, start with what the drawing must prove.
What is the DGPS full form?
Behind the DGPS full form sits a method that pairs two satellite receivers so that the known error at a fixed one is removed from a moving one. For anyone asking what is DGPS, "differential" means comparing a measured position with a trusted one.
Strictly, the global positioning system (GPS) is the United States constellation of at least 24 satellites about 20,200 km up1. Survey receivers also track India's NavIC and other constellations, yet searches for the "DGPS survey full form" still use the older name.
What does DGPS mean in plain words?
The DGPS meaning, in plain words, is a satellite receiver checked against a point you already trust, with that check passed on to every nearby point. Satellite based positioning alone carries shared errors that the check removes.
On site, the base station stands on a pillar or benchmark with fixed coordinates and acts as the reference station for the job. A rover on a pole visits each plot corner or pipeline bend, tracking the same GPS signals through the same air, so most errors match and cancel.
Why does an ordinary GPS reading need correcting?
A satellite signal is delayed by clock drift, orbit errors, the atmosphere and reflections. A slip of a few billionths of a second becomes metres on the ground. Official United States figures put a good single-frequency receiver within about 2.2 m horizontally for 95% of the time2, which suits driving directions but not a boundary pillar.
Clock drift, orbit error and most atmospheric delay are shared by receivers a few kilometres apart, so the base removes them. Multipath, where the signal bounces off a wall or tin roof, and the electronic noise inside each unit stay local and do not cancel. A rover under a dense neem tree can give a poor fix beside a perfect base.
How does DGPS work, step by step?
The DGPS working principle has four steps: the base computes a position, compares it with its known coordinates, and sends the difference to the rover. The rover applies that difference live or later in the office, which is how DGPS works on every survey we run.
- Base set-up over a Survey of India control point or a project benchmark.
- Error measured each second, as the base compares where the satellites place it with where it truly stands.
- Correction sent to the rover as an RTCM message over UHF radio or a mobile data link.
- Rover corrected: the GPS receiver on the pole applies it and reports a "fixed" or "float" solution.
Code-based DGPS corrects the coarse ranging code and stays sub-metre, as in older marine navigation. Carrier-phase RTK (real-time kinematic) also tracks the carrier wave, giving the centimetre accuracy that plot and layout drawings need. One base serves reliably for roughly 10–20 km3. Further out, ground based reference stations take over: the Survey of India CORS network quotes about ±3 cm3, and Haryana's revenue mapping draws on 19 such stations4.
Where a shed roof or flyover hides the sky, our crews fix two or three DGPS points in the open. Work then continues under cover by total station, as shown in the total station survey process step by step.
DGPS, RTK, GAGAN and CORS at a glance
| Method | Reference source | Typical accuracy | Common use |
|---|---|---|---|
| Code-based DGPS | Own base or beacon | Sub-metre | Navigation, rough mapping |
| RTK (single base) | Own base on a known point, radio link | 1–2 cm horizontal, 2–3 cm vertical | Plot corners, layouts, route control |
| Network RTK / CORS | Permanent stations, internet link | About ±3 cm (Survey of India figure) | Surveys where a private base is not practical |
| SBAS (India's GAGAN) | Geostationary satellites run by ISRO and AAI | Metre level | Aircraft approach guidance |
GAGAN was built by ISRO and the Airports Authority of India and certified by DGCA for aviation use5; it is not a survey-grade service. A DGPS fix shows nothing buried below, so before you excavate, see Call Before You Dig in India.
Where is a DGPS survey used?
A DGPS survey is used wherever a coordinate must be right to a few centimetres and repeatable months later. Common jobs we handle around Delhi NCR:
- Plot and farm boundaries: corner coordinates and an area statement before a sale or a bank loan.
- Drone ground control: targets fixed so that the orthophoto lines up with the ground.
- Pipeline and road alignments: centreline points every 25 or 50 m, with bends and chainage.
- Utility mapping: radar scan lines tied to real coordinates for a GIS; to see them in a report, learn about GPR survey deliverables.
For one district's figures and turnaround, see what a DGPS survey in Faridabad costs.
What does a DGPS survey cost with Mezux Touch?
A plot up to 1 acre starts at ₹12,000; plots of 1–5 acres are ₹2,500 per acre with ₹12,000 as the minimum; control points along a route are ₹3,000 each. GST is extra. Four company-owned base and rover sets work in your chosen grid, often UTM zone 43N. Inside Delhi NCR, the team is on your plot that day or the next working day. Plots in other states are handled by a resident surveyor of that state, and the receivers go up immediately or within a single working day. Should mobilisation or travel apply, the quote prices it separately. A drawing set in DWG and PDF, a spreadsheet of coordinates (Excel or CSV) and a Google Earth file follow roughly 3 working days after the visit.
Share a location pin or the plot papers, tell us the drawing's purpose and ask about survey rates; what comes back is a written quotation with the final amount.
Sources
- GPS.gov (U.S. government), "Space Segment" – constellation size and orbit. www.gps.gov
- GPS.gov, "GPS Accuracy" – single-frequency receiver performance and augmentation. www.gps.gov
- Survey of India, "Note on RTK and CORS" – single-base range, network spacing, ±3 cm accuracy, RTCM formats. Surveyofindia.gov.in
- The Tribune, "Soon, clearly demarcated plots in Haryana to be just a click away", 28 April 2025. www.tribuneindia.com
- Inside GNSS, "GAGAN — India’s SBAS" – developers and DGCA certification. insidegnss.com
Frequently asked questions
In surveying, what is the full form of DGPS?
Differential Global Positioning System. On site it normally means a base and rover pair working in RTK mode to give centimetre-level coordinates.
Is DGPS the same as RTK?
RTK is the most accurate form of DGPS. Both use a base over a known point, but RTK also follows the signal's carrier phase, lifting accuracy from sub-metre to 1–2 cm.
Can a mobile phone do a DGPS survey?
No. A phone uses a single receiver with no base correction and is often several metres out, so it cannot fix a boundary pillar or a design level.
How far from its base can the rover work?
For single-base RTK, roughly 10–20 km. Beyond that the air above the two receivers differs too much, so a reference network or a static session is used.
Does DGPS work under trees or inside a shed?
Poorly or not at all. Blocked signals spoil the fix, so hidden points are taken by total station from open-sky DGPS control.
Can DGPS find underground pipes or cables?
No, it only fixes surface positions. Buried services are located with ground penetrating radar and cable locators; see GPR scanning details for how that survey is done.
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Written by Saniya Parveen · Technically reviewed by Rahul Rai · Updated 8 November 2026