A novel real time cycle slip detection and repair method for a single dual-frequency GNSS receiver

摘要

This paper develops a novel real time cycle slip detection and repair method for a single dual-frequency GNSS receiver. This method is based on several carrier-phase linear combinations, including WL (1, -1), Ultra-WL (-3, 4), NL (1, 1), GF (60,-77). First, we use the mean code range rate which is estimated by the former 10 code range data to detect and repair the big cycle slip. In this step, the big cycle slip is detected and repaired; however, some extra small cycle slip will be introduced into the carrier phase data. Second, the variation of the WL combination is used to detect the different cycle slip on L1 and L2 and the variation of the Ultra-WL combination is used to judge which frequency the cycle slip occurs on. With respect to the same cycle slip on L1 and L2, we use the variation of NL combination when the elevation of the satellite is low since it has lower noise than GF combination and the NL cycle slip is twice as L1 or L2 and use the variation of GF when the elevation of the satellite is high since the variation of the ionosphere delay is very smooth. After that, there are still some cycle slips with the same size and sign which occurs continually in every epoch on L1 or L2. For these cycle slips, we use the mean ionosphere residual method since the ionosphere residual is the same in all the 10 epochs. Finally, we can detect and repair all the cycle slip larger than 1 cycle in real time.