The invention discloses a Beidou
satellite-based three-frequency double-
ionosphere-free combined precision single-point positioning model and method, and relates to the technical field of
satellite positioning. The method comprises the following steps: S1, receiving four Beidou positioning
frequency band signals B1I, B3I, B1C and B2a, a PPP-B2b
signal and a broadcast
ephemeris in real time, and decoding; s2, matching the PPP-B2b
signal with a broadcast
ephemeris, correcting a calculation result of the broadcast
ephemeris by
satellite orbit correction information to obtain a real-time
satellite orbit coordinate, and correcting a broadcast ephemeris
clock error to obtain a real-time accurate
clock error; and S3, combining the observation values of three frequencies of BDS-3 in pairs, creating two groups of non-
ionosphere observation equations for each satellite, and constructing a three-frequency double-
ionosphere combination model. According to the method, the BDS-3 three-frequency observation value is reasonably utilized, the satellite-based PPP positioning performance is improved, and the service range of the PPP is expanded.