Antenna Phase Center Correction for BeiDou Navigation Satellite

Presently, much of the errors caused by the B3 frequency, antenna phase center offset is corrected by the satellite clock a₀ parameter. Errors caused by the variance of different frequencies are corrected by timing group delay(Tgd) parameter for BeiDou navigation satellite system(BDS) through navigation messaging. In order to improve the broadcast ephemeris, we put forward a satellite antenna phase center offset correction and fitting broadcast ephemeris methods. The two approaches are compared in two ways, including the influence on user ranging error and precise point positioning. The results show that the two methods can correct most errors caused by antenna phase center offset. The correction accuracy of the new method was improved by 76% compared with the method using satellite clock a₀ parameter, and the positioning accuracy was improved by 12.5%. Accuracy is not affected by time-space factor. The positioning accuracy when correcting the satellite position before ephemeris fitting is about 38.1% higher than when satellite antenna, phase center offset is not corrected. The correction Tgd residuals of the variance of different frequencies of the antenna phase center are analyzed. The results show that the influence is at the mm order, so we can correct the variance by Tgd parameter.