| This article systematically regards the GNSS dynamic relative positioning on the medium and long baseline as research subject, which includes multipath effect error, cycle slip detection, troposphere delay error, ionosphere-free combination and Single epoch data decoding,etc. Through the theoretical research and derivation, dynamic relative positioning baseline calculating software module has been developed using FORTRAN which based on the CVF6.6 programming platform. With some medium and long baseline experiments, algorithmic routine software has been tested, which results are analysised. The main research contents of this articles are as follows:1) The principle and data processing’s method of undifferenced relative model are explained systematically, which include functional model and stochastic model of relative positioning. Based on this, subsequent research content is researched;Analysising the the multipath effect in relative positioning. Choosing different types of pseudo-range observations and calculating multipath effect value in observation period, analysising results shows that the multipath effect presents a sequence of random variation over time. In the end, some effective actions are given in order to control the multipath effect;2) In order to research the broadcast ephemeris’ calculation error and can meet the requirements of long baseline positioning or not, this article calculates satellite orbit information using broadcast ephemeris through the way of computer programming and time extrapolation. By comparison with actual results show that the calculation error within the allowable range. In addition, through the baseline length error and the relation between the broadcast ephemeris error, the influence of the broadcast ephemeris calculation error shows that the broadcast ephemeris can satisfy completely the requirements of dynamic relative positioning accuracy; In this article, the treatment strategy of cycle slip is just detecting without repairing. Summarizing the detection method of different categories and choosing the ionosphere residual error method, phase pseudo-offset and M-W combination method as three kinds of commonly used detection method, superiority-inferiority of three cycle slip detection methods is compared with CORS station data;3) Considering the troposphere delay error influence and statisticing analysis of different zenith tropospheric delay calculation model and related projection function, applicability in different baseline model is studied. Based on this, spatial-temporal Characteristics Analysis of two ZTD Correction Models is presented, which analysis the precision analysis in latitude, elevation and observation time. After, the global area is zoned in space according to root mean square error(RMS) and average relative error(ARE). The new method of ZTD model modification is put forward to improve the model correction accuracy;4) In order to eliminate the ionospheric delay error on the result of relative positioning, Considering the ionospheric delay error influence and comprehensive studying different forms of ionospheric combination(double frequency, Uof C, and crossover combination), this article gives different forms of iono-free combination observation combination sets in double and three frequency mode. Based on this, the optimal combination set is choosen by evaluation method of iono-free combination sets. compared with TCAR/CIR and matrix transform method, the optimal combination set shows its accuracy;5) In order to implement dynamic relative positioning and ensure the observations’ number of single epoch condition, a new single epoch ambiguity fixed method is pointed out, with dynamic experiment proves its validity; In addition, dynamic relative positioning module of baseline calculating is developed with FORTRAN, four medium and long baseline tests’ result show that algorithm can realize cm dynamic positioning precision of most epoches. |
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