Research on the method of detecting small single-frequency cycle-slips based on EEMD-HT of BDS

For the purpose that cycle-slips could be detected and repaired to increase navigation precision, a method based on ensemble empirical mode decomposition (EEMD) was proposed to detect small single-frequency cycle-slips. First of all, a second-order different equation was solved according to observations of pseudo-range and carrier-phase. Next, the differential sequence obtained was used for detecting cycle-slips and decomposed via EEMD into several intrinsic mode functions. Furthermore, all IMF variables were transformed into local instantaneous amplitudes through Hilbert transform, while areas where cycle-slips appeared could be detected based on the point at which the amplitude was the highest. At last, the method put forward in this paper was empirically verified to be effective for detecting single-frequency carrier phases to observe cycle-slips and accurate for detecting small cycle-slips within one to five cycles.