GPS carrier signal parameters estimation under ionosphere scintillation

This paper presents a post-processing carrier tracking algorithm to track GPS carrier phases under scintillation conditions. The method utilizes GPS signal frequency estimation generated by a frequency lock loop and subsequent frequency correction and interpolation procedures to aid a carrier phase lock loop. The frequency estimation provides information on the signal dynamics. By removing the known dynamics from the input signal, the carrier phase lock loop can track the reduced dynamics signal with a smaller bandwidth to limit noise contributions. Simulated scintillation signals based on models and toolkit provided by Cornell University GPS Laboratory are used to evaluate the dynamic reduction-based PLL (DRP), a conventional PLL, and frequency-assisted PLL (FAP). The results show that the DRP method outperforms the conventional PLL and FAP in carrier phase error under all scintillation levels tested and is comparable or slight superior to the PLL and FAP in number of cycle slips for most test cases.