Single-Frequency GNSS-Based Measurement-Domain Attitude Determination Algorithm with Inter-system Bias Calibration

Under satellite-deprived environments, the accuracy and continuity of the traditional GNSS-based attitude determination methods would be degraded. In this contribution, we derive the tightly coupled measurement-domain approach for single-frequency attitude determination, which could improve the performance of ambiguity resolution and attitude determination accuracy. However, the appearance of inter-system bias (ISB) and inter-frequency bias (IFB) are due to hardware delays and frequency inconsistencies between systems. Therefore, the time-domain stability of ISB is applied to construct ISB estimation observations, to eliminate the influence of ISB on integer ambiguity resolution. The narrowly spaced frequency of GPS L1 and BDS B1 effectively suppresses the influence of IFB by roughly estimating the single difference ambiguity of the pivot satellite at the same time. The kinematic and static experiments are conducted in simulated urban areas, which are based on single-frequency observations from GPS L1 and BDS B1. The result shows that the proposed method can enhance the accuracy and continuity of attitude determination when compared with the traditional MAD methods.