Research On The Theory And Algorithm Of Triple-frequency GNSS Precise Positioning

With the successful operation of BDS navigation system of our country, triple-frequency GNSS navigation and positioning technology can be really used. Based on the theory of the dual frequency GNSS, studying and developping the technologies of triple-frequency GNSS navigation and positioning can improve the precision and efficiency of GNSS navigation and positioning further. And with the operation of BDS, more GNSS satellite resources can be used, studying the integrated GNSS navigation algorithm can broaden the application scope of GNSS. Based on the analysis above, this paper mainly aims at studying the theory and methods of triple-frequency multi-system GNSS precise navigation and positioning, the main achievements and innovations are as follows:1. Based on the deduction and analysis of the classical stochastic model modeling method, the sliding polynomial fitting algorithm is used to modify the pseudorange observation data quality analysis method, which is based on the triple-frequency pseudorange/carrier phase geometry-free combination observations. And the modified method can realize real-time estimation of a single station and single satellite pseudorange observation precision. The observation correlation of two receivers betweent a baseline and the time correlation between two epoches can be analysized by differing between two stations and between two epochs of pseudorange/carrier phase geometry-free combination.2. The observation data quality analysis method is advanced based on three linear independent pseudorange/carrier geometry-free ionosphere-free combinations, and this method can realize real-time estimation of the pseudorange random model with considering the correlation between observesation. Based on the assumption that all the carrier phase observation is independent and has the same observation precision, the carrier phase observation error can also be estimatied in real-time. Using the methods above, the eorrors comparisons between the different frequency observations of GPS and BDS under the same observation conditions have been made.3. The proposed extra-wide-lane, wide-lane combination carrier multipath mitigation algorithm based on the linear combination of multi-frequency carrier multipath can guarantees that the linear combination can not make multipath of extra-wide-lane, wide-lane accumulated, and so this method can improve the precision of navigation and postioning based on the extra-wide-lane, wide-lane combination observations.4. At first, the unified formula of pseudorange multipath extraction based on the triple-frequency combination observations is derivated. And then, through analysizing the pseudorange multipath extraction effect based on different pseudorange/carrier phase observation combinations, some conclusions are drawed as following:the effect of pseudorange multipath extraction based on triple-frequency first-order ionospheric correction is the best, pseudorange multipath extraction based on second-order ionospheric correction may exaggerate the observation noise; when only using the dual-frequency combination to extract the pseudorange multipath, the pseudorange multipath extraction effect based on the dual-frequency combination with the the largest frequency difference is the best; when using the same observation to extract different pseudorange multipath, pseudorange multipath extraction effect on the observation with the maximum frequency is the best.5. Cycle-slip repair of the triple-frequency TurboEdit may be not always correct, in order to solve this problem, an adaptive search algorithm of cycle slip correction is advanced based on the the ambiguity search theory. The algorithm does not need to consider the variation of ionosphere delay between epoch, and can automatically adjust the search range of cycle-slip. Compared with the cycle-slip directly repair method and searching method, the adaptive search algorithm of cycle slip correction is less affected by noise and error, and can be sure the cycle-slip correction is correct.6. Basd on the combination observation theory, the triple-frequency pseudorange/carrier geometry-free ionosphere-free combination and the two epoch difference triple-frequency carrier phase geometry-free combinations are constructed, and both the two combinations can effectively weaken the influence of ionosphere delay on cycle-slip detection. The error characteristics of the two combinations have been compared and analyzed when selecting the best triple-frequency pseudorange/carrier geometry-free ionosphere-free combination and the best triple-frequency carrier phase geometry-free combination. The TurboEdit algorithm weakening the influence of ionospheric delay and the ionosphere cycle-slip processing method based on GIF (Geometry-free and Ionosphere-Free, GIF) combinations are proposed based on the two kinds of combinations above. Experiments show that both the two methods can realize the detecting and repairing all the smaller cycle-slips in 2 cycles.7. The ambiguity resolution method based on the mixed integer least square model is studied. The modified BKZ lattice reduction algorithm is proposed based on the Lattice theory. And this method can effectively improve the lattice reduction effect of LLL, and also can improve the BKZ lattice reduction efficiency by introducing the HE-LLL into BKZ algorithm. So this method helps to improve the efficiency of ambiguity fixing.8. The TCAR ambiguity fixing effect has been verificated by the measured data, and an modified algorithm is proposed based on K-Bootstrap search to sovle the problem of TCAR. And then factors which affect the long baseline ambiguity fixing have been analysis. The fact has been proved that every narrow lane combination in the triple-frequency carrier geometry-free ionosphere-free combination, which is made up with two extra-wide-lane combinations and one narrow lane combination, has the same error. And the triple-frequency carrier geometry-free ionosphere-free combination above is just a special case of the triple-frequency carrier geometry-free ionosphere-free combination, whose coefficients of the combinations meet the constraints i+j+k=1.GIF rapid ambiguity resolution method is advanced based on triple-frequency pseudorange/carrier geometry-free ionosphere-free combination and triple-frequency carrier geometry-free ionosphere-free combination, this method can realize the rapid ambiguity solution of medium and long baseline. This method can weaken the influence of ionosphere delay on ambiguity resolution and improve the accuracy of ambiguity resolution of the long baseline.9. With the research on the multi-system GNSS combination observation model and Kalman filtering method, the performance of multi-system GNSS dynamic RTK and integrated GNSS precise point positioning have been analyzed in detail, some conclusions are drawed as following: under the urban signal-shadowed observation condition, multi-GNSS system combination RTK can effectively increase the number of available satellites and improve the precision of navigation.In precise point positioning experiment, GPS\GLONASS\BDS three system precise point positioning technology alwayls has the optimal performance on static, dynamic positioning accuracy and static, dynamic convergence, and GPS\GLONASS dual system precise point positioning nearly has the same performance with GPS\GLONASS\BDS three system precise point positioning. GPS\BDS only can improve the performance of GPS dynamic positioning, while has no effect on improving the one of static GPS positioning and navigation.In the single system precise point positioning, the performance of GPS precise point positioning is the best, GLONASS second, BDS is the worst. But BDS can effectively improve its navigation precision and shorten the convergence time by integrating with other navigation system,...