Adaptive detection and modification algorithm of GPS cycle slips based on wavelet analysis

Based on the analysis of the causes and characteristics of GPS cycle slip, an adaptive detection and modification algorithm is proposed using the wavelet threshold de-noising theory. The original double difference of GPS carrier-phase is transformed with wavelet, and the singular values in the high-frequency coefficients are replaced by linear interpolation. Then the signal is reconstructed with the replaced high-frequency coefficients and the original low-frequency parts. The difference between the reconstructed signal and the original one is applied for cycle slip detection. The time and correction value of cycle slip are determined by the modulus maxima of the difference signal. Finally, an experiment was taken to test the method, and it shows that the method is effective for detecting and modifying the cycle slips of minimum value of one cycle, with minimum interval of one epoch.