CHE Ai-xia

(National Time Service Center, Chinese Academy of Sciences, Xi’an 710600, China)

Abstract: In order to guarantee the accuracy of BPL time signal, which is referred to UTC(NTSC) kept by the National Time Service Center(NTSC), it is necessary to calibrate the time signal, i.e., to determine the phase of timing calibration signal while the transmitted time signal is synchronized with the working clock for transmission. The principle and method for calibrating BPL time signal are demonstrated. Differing from the conventional calibration method, the standard zero crossing of the emission antenna current signal, instead of the basic timing signal of the timing control unit, is selected to calibrate the time signal in this method, so that the error caused by the deficiency of the accuracy of phase-locked control loop is eliminated and the precision of BPL time signal is improved. This method could be used as a general method for time signal calibration of Loran-C system.

Key words: BPL time signal; time calibration; correction to time signal