Calibration of Time Synchronization Error in Gps/sdins Hybrid Navigation

In this study, we analyzed the effect of a constant transmission delay that occurs in delivering measurements from a global positioning system receiver to a Kalman filter for an aided strapdown inertial navigation system and propose an efficient delay calibration algorithm. A new error model for the circular trajectories is derived to show that all the currently computed navigation variables converge not to the current true variables but to the neighborhood of the past true variables at the instant the delayed measurements were actually sampled. In order to eliminate the undesirable delay effects given various combinations of receivers and strapdown inertial measurement units, a simple delay calibration algorithm is proposed. The proposed algorithm is enabled by the vehicle's controlled maneuver, and advantageously requires no modification in onboard hardware.