Method for network-wide fixing of widelane ambiguities based on ionospheric correlation, apparatus, and system

A method for network-wide fixing of widelane ambiguities based on ionospheric correlation, comprising the following steps:

• Step 1, dividing all base stations in a continuous operational reference system (CORS) network into a plurality of independent ambiguity calculation units by means of superposed ionospheric pierce points;
• Step2, collecting four or more groups of fixed widelane ambiguities in each of the ambiguity calculation units;
• Step3, calculating widelane ionospheric delays corresponding to each group of widelane ambiguities collected to construct a regional ionospheric delay model;
• Step4, judging whether the widelane ambiguities are fixed falsely according to the regional ionospheric delay model, if the widelane ambiguities are fixed falsely, eliminating the falsely fixed widelane ambiguities, judging whether no fewer than four groups of remaining widelane ambiguity data are present, and if no fewer than four groups of remaining widelane ambiguity data are present, repeatedly executing Step3;
• and if fewer than four groups of remaining widelane ambiguity data are present, exiting a calculation process;
• Step5, if no false fixing is found in a process of judging false fixing of widelane ambiguities in Step4, continuously judging whether unfixed widelane ambiguities exist in a current ambiguity calculation unit, and if the unfixed widelane ambiguities exist in the current ambiguity calculation unit, interpolating widelane ionospheric delays corresponding to the unfixed ambiguities by means of the regional ionospheric delay model in Step3, and calculating alternative values of the widelane ambiguities and widelane ionospheric delays corresponding to the alternative values;
• and
• Step6, viewing whether the alternative values of the widelane ambiguities calculated in Step5 meet a judgment condition, if yes, adding the alternative values into Step3 to iteratively construct the regional ionospheric delay model, and if no, returning to Step5 to perform calculations of fixing the widelane ambiguities gain.