Research On Anti-jamming Performance Of Frequency Agility Radar

In the field of target detection and tracking,the current mainstream moving target detection technologies are based on fixed-parameter pulse doppler radar(PD).PD radar has the advantages of low computational complexity and is easy to fulfill real-time processing.However,with the development of high-speed sampling and copy-and-forward techniques for wideband radar signals,Digital Radio Frequency Memory(DRFM)is widely used for active coherent interference.However,the current parameters-fixed PD radar can easily intercepted by the enemy's interference aids.These devices can quickly analyze the parameters of the intercepted radar signal,and quickly generate interference signals and repeat the interference signal at the current or next radar pulse repetition interval to implement high-fidelity interference.On this basis,a variety of interference signals are generated,and as a sequence these interference poses a serious threat to the radar.In order to enhance the anti-jamming performance of radar,this thesis proposes a new frequency-agile radar system with PRF-jittering.Although frequency agile and PRF-jittering radar have excellent anti-jamming capability,the hopping scheme leads to the continuous echo signal phase in a CPI,so the FFT-based MTD method of traditional parameters-fixed PD is no longer applicable in this scheme.In this thesis,relevant researches are carried out to fulfill target detection signal processing technology for frequency agility radar with PRF jittering: Firstly,the echo model of frequency agile and PRF-jittering radar is deduced,and the influence of carrier frequency agility and repetitive frequency jittering on the nonlinear phase shift in the slow time domain for coherent accumulation is analyzed.Then this thesis establishes a signal processing model of carrier frequency and PRF simultaneous agility radar based on Compressed Sensing,and jointly estimates the high resolution distance-velocity parameters of the detection target.The effectiveness of the algorithm was validated by simulation and field measurements.The performance analysis and design of the dictionary matrix in the Compressed Sensing model of the carrier frequency and PRF simultaneous agility radar is studied.Firstly,from the perspective of ambiguity function,velocity unambiguity property of agility radar is analyzed.Then,the relationship between the dictionary characteristics and sparsity is analyzed.The optimization function of the dictionary matrix is constructed and is solved by the simulated annealing method to optimize the radar carrier frequency agile sequences and PRF-jittering sequences.Evaluation of anti-clutter performance and anti-jamming for the proposed radar scheme are carried out.We analyzes the column correlation of the dictionary matrix for both parameters-fixed radar and carrier frequency and PRF simultaneous agility radar to evaluate the anti-clutter performance of the proposed radar.At last,the anti-jamming performance against typical deception interference for frequency agile radars is analyzed.