Methods for monitoring and correcting GPS-clock

Infected by jamming-signal and losing satellite tracking, GPS-clock is difficult to satisfy the requirement of synchronous control with high reliability. Based on the precision interaid between high precision oscillator and GPS-clock, methods for monitoring GPS-clock by comparing to oscillator are proposed in this paper. The variance of GPS-clock and the accumulation error of oscillator are estimated with the presented model of minimum mean-square value. And methods for correcting GPS-clock on-line are developed. The device for high precision clock with high performance/price ratio is implemented. It has been applied in power system protection and control.