Research On TDOA/FDOA Parameters Estimation For Dual-Satellite Interference Source Location System

With the development of satellite communication technology and the wide use of related business,satellite interference events occur more frequently.According to the European Telecommunications Satellite Organization(EUTELSAT)'s statistical information,hundreds of such events happen every year,exerting serious influence on the national economy and people's life.Moreover,due to the late start of the related technology research in China,there is still a large gap between our country and the developed ones.Therefore,it's an urgent requirement to design high precision interference location system.The research of this paper is based on dual-satellite TDOA/FDOA interference source location system and the system is one of the most widely used location systems now.The commonly used location methods were first introduced to demonstrate the advantage of using TDOA/FDOA after comparison of these methods in this paper,then the relevant theoretical knowledge of the system was also presented to conclude that increasing the accumulation time can improve the location accuracy.In this paper,in order to facilitate follow-up research,the simulation of interference signal was first studied by using software technology.With satellite ephemeris,the radial velocity between satellite and interference source,satellite and monitoring station were calculated to overlay the signal with code Doppler frequency and carrier Doppler frequency,then adding the signal with noise can generate data of interference signal.On the basis of the simulation data,a kind of long-time accumulation algorithm is proposed in order to solve the problem that the SNR of cross-ambiguity function is lower.The algorithm first splits the input data into several sections,then each section will be processed to compensate the code Doppler effect and carrier Doppler frequency by using Sequential Quadratic Programming(SQP)algorithm which is faster in computing.After merging these sections the SNR could get improved.On the premise that the simulation result is noticeable for stationary interference source,the long-time accumulation algorithm mentioned as above is applied to moving interference source and the simulation outcome still yielded good results.