The Analysis and Modeling of Intersystem Biases Between GPS and BDS

Abstract

Receiver hardware delay is one of the error sources which affect ambiguity resolution and positioning. In this contribution, differential receiver hardware delay between GPS and BDS, namely differential phase and code intersystem bias (ISB), are estimated together with other parameters using single differential (SD) observation, and analyzed by Fast Fourier Transform (FFT). The experiment shows that the differential ISBs are close to zero for the baseline using two identical receivers, and can be neglected when taking the measurement noise of phase and code into account. However they become significant for receivers which are of different types. According to FFT, the ISB time series only contains the constant term, and no trend and periodic terms are included. The model can be established on the basis of the characteristics of ISB and is used for prediction and calibration. Taking into account the ISBs correction, the success rate of ambiguity resolution is up to 99%. The mean values are −0.3, 0.6, −1.7 mm and standard deviations are 2.9, 3.4, 6.3 mm for baseline component in North, East, and Up directions, respectively. The result shows that the prediction and calibration for ISB are feasible.