Research Of Direction Finding Techniques Based On The Overlap Signals With High Resolution

In the modern complex electromagnetic environment, radar system is usually equippedwith decoys. In order to resist against anti-radiation missile attack, and protect the radar,Decoy pulse covers both the former and the later edges of the radar pulses. Considering theproblem that the traditional passive direction finding based on phase comparison is unable todistinguish multiple incident signals, how to improve the angular resolution of the spatialspectrum estimation direction finding method is researched deeply.For the characteristics that the synthetic pulse is constructed of overlap signals when thedecoy and radar pulse signal reach the anti-radiation missile receiver system, one spatialspectrum estimation algorithm based on overlap signal is proposed. Firstly, the former edgedata of the overlap signal is collected. Then the amplitude information is applied foramplitude normalization, wiping the noise by moving average, extracting trip point bydifferential, the intelligent interval divide of the overlap signal is completed. Finally,according to the result of the interval divide, the covariance relationship of the overlap signalis exploited, based on the covariance differential MUSIC algorithm for overlap signal, thedirection-of-arrival (DOA) of the incident signal is estimated step-by-step, the DOA of eachsignal is obtained and multiple targets resolution is achieved. The simulation results verify thefeasibility and effectiveness of the spatial spectral estimation algorithm based on the overlapsignal.In the real passive direction finding system, the amplitude and phase inconsistency errorof the antenna channels exists, and the ideal signal model does not match the actual signalenvironment. A joint calibration method for channel inconsistent is proposed. By amplitudenormalization and phase0°calibration, it can calibrate the amplitude and phase inconsistencyerror of the antenna channels. Simulation analysis and system testing verify the correctness ofthe proposed method, the angular measurement accuracy and angular resolution probability ofdirection finding system are improved.With the existing hardware and measured environment in actual passive measurementsystem, it can test the ability of the MUSIC algorithm to distinguish signals with arrivingsimultaneous. The results of the intelligent interval dividing method have been obtained byanalyzing the receiving data of overlap signal in the actual finding system. Testing the multiple targets resolution performance of the spatial spectrum estimation method based onoverlap signal, the results show that the proposed method can improve the multiple targetsangular resolution.