High-precision baseline resolving method by use of multisystem GNSS observed values

The invention discloses a high-precision baseline resolving method by use of multisystem GNSS observed values. First of all, inter-station single-difference observed values are constructed by performing subtraction between stations at the two sides of a baseline on a pseudo range and a carrier wave phase observed value of each frequency of each GNSS system, afterwards, the rank defect problem of a normal equation is solved by taking a pseudo range hardware delay of a certain type of observed values as a reference, influences of a combined UPD are removed by performing estimation processing on floating point single-difference fuzziness according to the property of each GNSS system, an integer cycle characteristic of the single-difference fuzziness is recovered, and thus high-precision resolving of the baseline is realized. According to the invention, the defects existing in a conventional multisystem GNSS baseline resolving method are solved, and the method has the advantages of rigorous theory, simple model,