Magnitudes of parameter adjustments Major contributions to GPs measurements Pseudorange data: Range from satellite to receiver, satellite clock and receiver clock (+10 cm) Phase data: Range from satellite to receiver, satellite clock oscillator phase receiver clock oscillator phase and number o cycles of phase between satellite and receiver (+2 mm) Range from satellite to receiver depends on coordinates of satellite and ground receiver and delays due to propagation medium(already discussed) How rapidly do coordinates change? Satellites move at 1 km/sec receivers at 500 m/s in inertial space To compute range coordinates must in same frame 04/17/02 12.540Lec1804/17/02 12.540 Lec 18 5 Magnitudes of parameter adjustments • Major contributions to GPS measurements: – Pseudorange data: Range from satellite to r eceiver, satellite clock and receiver clock (±10 cm) – Phase data: Range from satellite to receiver, satellite clock oscillator phase, receiver clock oscillator phase and number of cycles of phase between satellite and receiver (±2 mm) • Range from satellite to receiver depends on coordinates of satellite and ground receiver and delays due to propagation medium (already discussed). • How rapidly do coordinates change? Satellites move at 1 km/sec; receivers at 500 m/s in inertial space. • To compute range coordinates must in same frame