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Table 2 Data processing strategy

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

 

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)