DGPS
The DGPS (Differential Geographic Positioning System) Survey
These are surveys which are carried out using the differential GPS. It achieves higher positional accuracy by making use of the differential capabilities of two GPS antenna linked by a radio signal.
The DGPS Survey main features are:
· Position is determined by distance from at least 4 satellites
· Time taken by signal to travel from satellite to antenna used to determine the distance.
· The base station calculates the difference between the specified coordinates of its location and those indicated by the satellites.
· The base is continuously broadcasting a signal to the rover of this difference.
· The rover then uses this same difference to accurately determine it’s location.
DGPS Advantages
· Higher accuracy (+/-0.045m)
· Real time data
· Worldwide coverage
· 3D survey results
· 24 hours availability
· Not affected by cloud cover
DGPS Application
· Topographic surveys
· Control establishment and densification
· Positions, lines and levels setting-out
· Azimuth determination
· Collar pick-ups (X;Y;Z)
What is a differential GPS?
Differential Global Positioning System (DGPS) is a method of providing differentialcorrections to a Global Positioning System (GPS) receiver in order to improve the accuracy of the navigation solution. DGPS corrections originate from a reference station at a known location.
What is a mapping GPS?
The global positioning system (GPS) is a network of satellites that orbit the earth and send a signal to GPS receivers and Navigation devices, giving them the precise location, speed, and if you are in an aircraft or up a mountain, altitude.
How accurate is the GPS?
The United States government currently claims 4 meter RMS (7.8 meter 95% Confidence Interval) horizontal accuracy for civilian (SPS) GPS. Vertical accuracy is worse. Mind you, that’s the minimum. Some devices/locations reliably (95% of the time or better) can get 3 meter accuracy.