Research On Subband Spectrum Detection Technology Based On Dynamic Channelized Receiver

With the increasing complexity of the electromagnetic environment,the bandwidth,location,center frequency and the number of channels contained in radar signals often change dynamically during the reception process,which brings more and more severe challenges to the development of broadband digital receivers.In order to meet the current radar signal detection requirements,it is an inevitable trend to develop a dynamic digital channelization technology that can be flexibly configured and can handle large instantaneous bandwidth signals across channels.Channel detectionis the most important part in the research of dynamic channelized receiver,which directly affects the following processing of radar signals such as frequency measurement,recognition and sorting.In addition.If the real channel of the signal can not be detected correctly,the dynamic channelized receiver can not reconstruct the complete input signal.Therefore,this paper studies the dynamic digital channelized receiver and the sub-band spectrum detection technology as follows:Firstly,a dynamic digital channelized receiver design method based on the whole-band decomposition is studied in this paper.By adding a whole-band decomposition link,the whole frequency band is divided into several sub-channels with complementary and non-overlapping spectrum,and then the corresponding analysis filter banks and integrated filter banks are designed to realize the complete reconstruction of input signal spectrum.However,this method does not take into account the fact that the energy distribution of cross-channel signals in subchannels is small,which results in inaccurate detection results.To solve this problem,this paper proposes a sub-band energy detection algorithm based on square spectrum,which improves the channel detection and decision module on the basis of adaptive energy detection combined with sub-band square spectrum detection algorithm.Simulation results show that this method can enlarge the gap between signal and noise,enhance the anti-noise performance of the system,and realize the fast and accurate detection of sub-band signals.Secondly,the design method of dynamic digital channelized receiver based on polyphase filter banks is studied in this paper.In view of the shortcomings of dynamic channelized sub-band spectrum detection algorithm in low SNR environment,this paper applies eigenvalue-based spectrum detection technology to dynamic channelized sub-band spectrum detection module according to the theory of random matrix.Based on the distribution characteristics of maximum eigenvalues of signal covariance matrix and the correlation of average eigenvalues of covariance matrix of all sub-band signal samples,three new algorithms for channelized subband spectrum detection are proposed,namely,Maximum Eigenvalue-Minimum Average Eigenvalue(MEMAE)detection,Improved Maximum-Minimum Average Eigenvalue(IMMAE)detection and Maximum-Minimum Geometric Average Eigenvalue(MMGAE)detection algorithm,and derived the expression of better decision threshold.By analyzing and comparing the detection performance of the above three algorithms,it is proved that the proposed algorithm is not affected by noise uncertainty,does not need to know the prior information of the signal,and can achieve better detection performance in low signal-to-noise ratio environment.