Research On The Inter-satellite Ranging Technique In Small Satellite Formation

There has been an increasing interest in small satellite formation flying, whichis an intensive satellite formation form. It is formed by a series of micro-satellite.The main difference between small satellite formation and traditional satellite isautonomous navigation, which requires the satellites to measure the relative statusbetween the stars in real time. Inter-satellite ranging is one of the important links. Inthe paper inter-satellite ranging technique is studied in the context of the formationof small satellite.Firstly, this thesis analyzes three main types of ranging methods: Carrier phaseranging, PN code ranging, carrier phase smoothing PN code ranging. Theadvantages and disadvantages of three methods are compared. Carrier phasesmoothing PN code ranging method combines with the advantages of carrier phaseranging and PN code ranging, and the accuracy of carrier phase smoothing PN coderanging between the two. So the thesis uses the method of carrier phase smoothingPN code ranging to measure the distance between satellites. Then the thesisestablish the mathematical model of inter-satellite ranging based on the analysis ofionosphere delay error; satellite clock error and the relativistic effects error, andselects two-way and dual-frequency ranging method from the starting point of theelimination of errors.Secondly, based on two-way pseudo-code carrier joint inter-satellite rangingalgorithm system is created. Simulation of ranging signal generation and transmittermodule, reception of the ranging signal and the PN code acquisition link,pseudo-code tracking and carrier tracking link and integer ambiguity solutions linkis conduct on. Ranging signal is pseudo-code phase modulation signal, pseudo-codeis modulated to the carrier and launch to in the space. Considering the acquisitiontime and amount of equipment, the thesis selects the capture method ofdelay-related. Pseudo-code tracking loop is utilized to obtain pseudo-code rangingvalue, while Costas loop is used as carrier tracking method to obtain carrier rangingvalue. And the combination of pseudo-code ranging value and carrier phase is usedto solve the integer ambiguity.Finally, the thesis analyzes the error produced by two-way pseudo-code carrier joint inter-satellite ranging algorithm, which contains the fixed error due to theacquisition and tracking and the relativistic and the random error produced byGaussian noise. According to the simulation results, the conclusion is draw thatranging error distribution is related to step length. Then the correction algorithmbased on statistical models is found to solve the fixed error and random error.,andfinally the ranging accuracy is improved.From the above, the thesis compares some kinds of ranging methods andchooses the method of two-way and dual-frequency carrier phase smoothing PNcode ranging, then establish the correction algorithm based on statistical models tosolve the fixed error and random error., and finally the ranging accuracy isimproved.