Ways of validating data
One Master Control Station, five Monitor Stations, and Ground Antennas comprise the control segment.
The Monitor Stations passively track each satellite continuously and provide this data to the Master Control Station.
GPS is a satellite-based positioning system operated by the United States Department of Defense (Do D).
GPS encompasses three segmentsspace, control, and user.
The receiver performs mathematical calculations to establish the distance from a satellite, which in turn is used to determine its position.
The GPS receiver knows where each satellite is the instant its distance is measured.
With mobile GIS, data is directly accessible to field-based personnel whenever and wherever it is needed.
It provides accurate positions for point, line, and polygon features.
By verifying the location of previously recorded sites, GPS can be used for inspecting, maintaining, and updating GIS data.
The base station receiver calculates its position based on satellite signals and compares this location to the known location.
The difference is applied to the GPS data recorded by the roving GPS receiver.
A GPS receiver must acquire signals from at least four satellites to reliably calculate a three-dimensional position.