A Novel Triple-Frequency Cycle Slip Detection and Correction Method for BDS

Abstract

A novel triple-frequency cycle slip detection and correction method for BDS is proposed to detect and correct cycle slips when the ionosphere is active. Firstly, two sets of phase combinations whose sum equals zero are selected, and the corresponding pseudorange coefficients are obtained by the optimization algorithm, which effectively reduces the ionospheric amplification factor. Then, a set of phase combinations whose sum not equal to zero is adopted to reduce the condition number of coefficient matrices, meanwhile, the ionospheric delay variation between the epochs of this combination data is estimated and corrected. Thus, three linear independence sets of geometry-free and ionosphere-free pseudorange-phase combinations are constructed. Finally, the covariance matrix of the combined observations is obtained by employing observation error and ionospheric correct error, accordingly, the search space and objective function of cycle correction are constructed, which improves the correction accuracy. Based on BDS triple-frequency observations, the experiment results show that the proposed method possesses a good cycle slip detection and correction performance under active ionospheric situation.