The Research And Application On Emitter Source Signal Used In Virtual Time Reversal Passive Direction Finding

Passive detection technology has a high security and concealment has been applied in various areas of electronic detection confrontation,so the study more accurate,to adapt to complex electromagnetic environment and complex signal form of passive direction finding algorithm is of great significance.Virtual time reversal(Virtual Time Reversal-VTR)algorithm in the electromagnetic environment,although the application of less,but it is undeniable that the algorithm in a complex environment,the accuracy and stability.The signal is in the form of a sinusoidal signal,a BPSK signal,a chirp signal,and a Link-11 signal.The signal is propagated as a radiation source to simulate the propagation of the multiplexed signal to the antenna array.The signal generation and simulation process is built on the Matlab GUI platform,and the parameter function and parameter selection of each module are analyzed in detail.The difference between the different forms of the radiation source signal is the difference between the simulation process.The propagation and reception process of the signal are mathematically modeled,and the difference between the propagation distance is deduced when the signal is propagated to the array receiving unit at the radiation source The difference in propagation time is simulated by the difference in the frequency components of the signal,and the difference in the signal propagation time is mapped to the difference in the phase when the signal needs to be calculated separately from the signal form.The addition of the received signal to the given size SNR is performed.The main module of the antenna array receiver to deal with the signal,including AD sampling module,RF receiver module,IF filter module and sampling module,and the value of each parameter in the module for data analysis and experimental comparison.According to the mathematical model and theoretical derivation of the virtual inverse algorithm,it is proved that the DOA estimation is accurate only when the pitch angle of the radiation source is less than 45 degrees.Therefore,in the process of generating the signal,The pitch angle remains within the valid range.In order to verify the correctness of the signal simulation and the DOA estimation capability of the different forms of the radiation source signal,the frequency range of all the signals is selected on the fixed frequency band of the Link-11 signal according to the principle of the control variable,and the radiation source The DOA error results of different signal forms are analyzed and compared with the signals at different positions on the whole loop of the fixed pitch angle,and the backward direction of the signal is analyzed by the inverse algorithm.The main advantages of the algorithm for virtual time reversal focusing are: First,the algorithm does not require any geometrical shape for the formation of the antenna,so all of the experiments in this paper are under the condition of a circular antenna array.Second,the algorithm has a low requirement for the electromagnetic environment,and has a high ability to detect weak signals.After adding a different SNR noise in a given set of parameters,the experimental results show that The algorithm has a high DOA estimation accuracy at very low SNR.Thirdly,the algorithm has no limit on the form of the signal.In this paper,we use the four different forms of radiation source signals to perform DOA estimation using the virtual anti-focusing algorithm under the same conditions.The estimation results are similar and are in the range of small errors It is proved that the algorithm has no limit on the signal form.In this paper,the DOA estimation system from the generation of the radiation source signal and the generation of the multi-channel communication signal to the position of the radiation source effectively solves the experimental conditions in the process of the direction of the passive communication station.