20-01-2012, 12:03 PM
Differential GPS
[attachment=16319]
Method of Differential Correction
The reference ground station(s) at known locations receive NAVSTAR signals.
Knowing position of the station, the pseudo-range to each SV is calculated based on the almanac
The measured pseudorange, PRM(t), is determined
The pseudorange correction is calculated as the difference
The pseudorange correction, PRC(t), and the Range Rate Correction RRC(t) are sent from the reference ground station
GPS – How it works
Constellation of more than 24 satellites
Known positions (at any time)
Each continuously transmits time and position data
Two frequencies (L1-1575.42MHz and L2-1227.6MHz)
Each orbits twice per day
Ground receiver (Your GPS receiver)
Calculates Position and Time
Times signal and calculates distance to each satellite received
Triangulates Latitude and Longitude
Calculates time
Must see a minimum of 4 satellites
[attachment=16319]
Method of Differential Correction
The reference ground station(s) at known locations receive NAVSTAR signals.
Knowing position of the station, the pseudo-range to each SV is calculated based on the almanac
The measured pseudorange, PRM(t), is determined
The pseudorange correction is calculated as the difference
The pseudorange correction, PRC(t), and the Range Rate Correction RRC(t) are sent from the reference ground station
GPS – How it works
Constellation of more than 24 satellites
Known positions (at any time)
Each continuously transmits time and position data
Two frequencies (L1-1575.42MHz and L2-1227.6MHz)
Each orbits twice per day
Ground receiver (Your GPS receiver)
Calculates Position and Time
Times signal and calculates distance to each satellite received
Triangulates Latitude and Longitude
Calculates time
Must see a minimum of 4 satellites