Cycle slips detection algorithm for low cost single frequency GPS RTK positioning

Abstract

Conventionally, cycle slips are detected by combining phase observations or phase/code observations. However, this is unsuitable for single frequency receivers in real time kinematic (RTK) positioning. Therefore, this study introduces an algorithm based on outlier detection concept to the detection and repair of cycle slip during GPS RTK positioning. The efficacy of the algorithm was verified on a low cost single frequency GPS receiver. To investigate the ability of the algorithm to detect error within a single cycle, minimum detectable bias (MDB) of less than one cycle was used as the index of success. Experiments verified the availability of the algorithm up to 96·12% (10° mask angle). The algorithm was able to accurately detect the time when cycle slips occur and precisely estimate their size in various simulated scenarios. Finally, tests were performed based on real data, and the results confirm that the proposed algorithm is applicable for single frequency RTK positioning.

Keywords:

• Cycle slips
• MDB (Minimum detectable bias)
• Kalman filter

The authors would like to thank the National Science Council of Taiwan for part of their financial support provided under the project of NSC 98-2221-E-159-022.