Improved Kalman Filtering Combined with Wavelet Transform for Single-Frequency Cycle Slip Detection

The carrier phase measurement technique plays a very important role in the high-precision positioning of the GNSS (Global Navigation Satellite System). In the carrier phase measurement, the carrier phase observation is often obscured by obstacles such as high-rise buildings or tall trees, resulting in cycle slips, which affect the high-precision positioning. Aiming at the problem of insensitive detection of small cycle slips in low-cost single-frequency receivers, a single-frequency cycle-slip detection method with improved Kalman filtering and joint wavelet transform is proposed. Firstly, the carrier phase observations are smoothed by improved Kalman filtering to eliminate the coarse differences to reduce the effect of observation noise and differenced between epochs to reduce the systematic error, then the double-differential detection sequence is constructed, and finally the improved Kalman filtering combined with wavelet transform method is used to detect and repair the cycle slips of the double-differential detection sequence. The experimental results show that the method has good cycle slips detection ability, solves the continuous cycle slips detection problem of Kalman filtering, and makes up for the defects that the wavelet transform method cannot directly calculate the size of cycle slips and repair cycle slips.