Research On Coherent Positioning System Of Ground-based Multi-station To Air

In the wake of the development of electronic reconnaissance,multi-station location and synthetic-aperture scouting are extensively used in aviation,guidance,electronic warfare and network location and other domains.There are conventional radar and passive location in target location,among passive coherent location is comparatively wide used in passive location.Therefore,this paper focuses on the key problems in multi station passive coherent location.At present,the common location and reconnaissance parameters include Time of Arrival(TOA),Time Difference of Arrival(TDOA),Frequency Difference of Arrival(FDOA)and Direction of Arrival(DOA).In this paper,the traditional method and the improved method are used to obtain the measured parameters,and then the target state,including position and velocity,is calculated.However,the positioning method of target state based on parameter measurements involves a series of nonlinear equations.Therefore,this paper first gives the traditional positioning method of stationary target in the case of ground-based multi-station and analyzes its advantages and disadvantages,then proposes long-term inverse synthetic aperture positioning method and moving target positioning method according to its disadvantages,and different localization methods are proposed for single target and multi-target with different transmitting signal models,the advantages and characteristics of radar positioning are compared with traditional radar positioning.In this paper,based on the multi-station air-to-air positioning model,the method of parameter measurement and target positioning and velocity measurement are studied,using abundant simulation modeling and detailed formula derivation.Specifically speaking,the main research contents and work progress are as follows:1.Due to the poor accuracy of traditional time difference and frequency difference measurement methods,this paper proposes a method to calculate the frequency difference based on two-dimensional rearranged interference correlation,which can avoid the problems of signal long sampling and system energy instability by traditional generalized cross correlation(GCC)method and cross ambiguity function(CAF)method in TDOA /FDOA parameter measurement.The simulation experiment and result analysis show that parameters can be estimated efficiently and accurately and estimation result has good accuracy and robustness.2.Different from the short-time TDOA / FDOA positioning method,this method will have poor positioning algorithm effect on the long-term received signal of the platform.Therefore,this paper explores the positioning model of the combination of long-term inverse synthetic aperture technology and TDOA / FDOA measurement method,the multi-target location is transformed into single target location by using the method of reducing dimension,and obtains the signal frequency transmitted by the radiation source by using the three-dimensional information of frequency,distance and azimuth,using the Fourier transform and band-pass filter to get the position information of the emitter,and the simulation modeling by controlling parameter such as frequency,signal form and so on verifies that the algorithm has a good localization solution effect.3.For the positioning problem under multi-station moving platform,the influence of the position and speed change of the platform on the results needs to be considered,and there is a demand for efficient and accurate positioning and solution of multi-target.Therefore,this paper proposes a location algorithm based on Total Least Squares(TLS)model is proposed which takes time and position errors into account,and uses the time distance error to construct the equation to solve the state parameters;An efficient and accurate positioning solution method based on multi-dimensional scaling(MDS)is also proposed,which uses the system of linear equations and error vector linearization to solve the localization parameters.The lower bound of CRLB and the simulation of the model are used to verify the good localization performance of the proposed method.