From: Instantaneous velocity determination and positioning using Doppler shift from a LEO constellation
Items | Velocity determination | Positioning |
---|---|---|
Satellites | LEO, GPS and GPS + LEO | LEO |
Estimator | Least square method | Extend Kalman filter |
Signal | GPS: L1/L2; LEO: L1/L2 | LEO: L1/L2 |
Sampling rate | 1 s | |
Elevation cutoff | 7° | |
Weight scheme | Elevation-dependent weight | |
Drift of ionospheric delay | IF combination | |
Drift of tropospheric delay | – | |
Sagnac effect delay rate | Equation (3) | |
Satellite position and velocity | Simulated precise satellite orbit file | |
Clock drift of satellite | Simulated precise clock file | |
Receiver coordinate | Approximate coordinates | Static: estimated; kinematic: estimated with process noise (scheme1: (1.5, 1.5, 1.5 m)2; scheme2: 0, 0, 0); dynamic: estimated with process noise ((1.5, 1.5, 1.5 m)2) |
Clock drift of receiver | Estimated | Estimated, white noise |
Receiver velocity | Estimated | Static: estimated with process noise (0.01, 0.01, 0.01 cm/s)2; kinematic: estimated with process noise (scheme1: (3.0, 3.0, 3.0 m/s)2; scheme2: (0.1, 0.1, 0.1 m/s)2); dynamic: estimated with process noise ((3.0, 3.0, 3.0 m/s)2) |