| In recent years,the official use of Beidou-3 Navigation Satellite System(BDS-3)marks the full completion of Beidou Navigation Satellite System(BDS).In the field of BDS positioning,cycle slip detection and ambiguity resolution are the key and difficult points of high-precision carrier phase data processing.BDS-3 satellite can provide multi-frequency observations to form more combined observations with better characteristics,which provides an effective solution.Therefore,this paper focuses on BDS-3 triple-frequency cycle slip detection and repair and ambiguity resolution.The BDS-3 multi-frequency combination observation theory is analyzed,and several BDS cycle slip detection and repair methods and triple-frequency ambiguity resolution methods are studied and discussed.The main research contents are as follows :1.The basic theory of BDS-3 multi-frequency combined observations is studied,and the calculation formula of the related parameters of the combined observations is derived.Three error characteristics of combined observations are analyzed and different calculation methods are given.The relevant parameter characteristics of BDS-3 triple-frequency linear combination are discussed,and three optimal linear combination selection schemes for short baseline and medium-long baseline are analyzed.2.The basic theory of cycle slip is expounded,and the working principle of several cycle slip detection methods is deduced step by step.The characteristics of MW combination observations of different satellites of BDS-2 and BDS-3 are analyzed experimentally.In view of the shortcomings of MW combination method for cycle slip detection of BDS-2 satellites,the elevation angle weight coefficient and sliding window are introduced for improvement,and the improved method is verified by experiments.According to the combination characteristics of BDS-3 triple-frequency data,the MW combination,GF combination and carrier pseudo-range combination with the best characteristics are combined to detect the cycle slip,and the insensitive cycle slip and random cycle slip detection and repair performance of the method are verified by experiments.3.The ambiguity resolution principle of geometry-free TCAR algorithm is studied,and the ambiguity resolution performance of this method for short baseline and medium-long baseline is analyzed through experiments.Aiming at the defect of geometric-free TCAR algorithm in processing medium and long baselines,the ultrawide lane combination group with the best noise impact factor is used to correct the ionospheric delay and improve the wide lane ambiguity fixing rate.The original pseudo-range observation and carrier phase observation are introduced to constrain and improve the narrow lane ambiguity fixing rate.The comparison experiments show that the improved method has improved the ambiguity fixing rate of wide lane and narrow lane,which is increased by 3.24 % and 8.13 % for 25 km baseline,and 5.74 % and13.88 % for 60 km baseline. |
