Zero-value calibration of the BeiDou monitoring receiver

In satellite navigation the receivers should be zero-value calibrated in order to measure the zero-value offset, and calibration modes of different types of receivers are also different, which should be studied with pertinence solutions. Through analyzing the characteristics of different types of receivers, the paper studies a zero-value calibration method of the BeiDou monitoring receiver (UniNAV MUE_C_001). UniNAV GSS8000 is chosen as the hardware simulator to calibrate the receiver, and the receiver zero-value is mainly affected by the phase relation (TtP) between 1PPS and 10MHz input signal. From the experiment result, under continuous operation test the receiver zero-value is monotone decreasing as TtP increasing. However, under on-off operation test the receiver zero-value presents periodic variation as TtP increasing, which is affected by the mode of clock adjusting. Meanwhile the experiment analyzes the calibration uncertainty, affected by RF filter and code ranging precision uncertainty of B3 2.3ns is better than B1 and B2 2.8ns. At last the paper tests a zero-baseline experiment with two calibrated receivers to verify the relation between TtP and zero-value calibration, and the calibration consistency is better than 0.5ns.