Research On High-resolution Imaging Technology Based On Pseudo-random Coded Radar

Radar imaging is a process of using radar scattered echo signals to invert important structural information of targets,which is of great significance in the military.Since various measures against radar have been studied in depth,it is particularly important to use signal forms with low probability of interception and to obtain high-resolution imaging results.Phase-coded radar has greater advantages in distance resolution and low intercept rate than traditional pulse radar.The pseudo-random code is simple to generate and easy to implement using digital techniques,and is often preferred as phase encoding.At the same time,high-resolution radar imaging technology,including ISAR radar one-dimensional imaging and two-dimensional imaging have also been extensively studied.Signal sparse representation analysis is a very interesting method of signal analysis.In the case of known over-complete bases and probe data,we can use as few as possible atoms in the over-complete base to represent known data to obtain the signal which is the most concise representation,and the effective information hidden in the signal.Signal sparse representation analysis provides theoretical support for high-resolution imaging.In this paper,pseudo-random code radar is used for the purpose of high-resolution imaging quality.Based on the signal sparse representation,multi-radar data fusion technology and compressed sensing technology are used as the line to deeply analyze and study the anti-interference characteristics and high resolution imaging method.The effects of high resolution imaging method is compared between pseudo-random coded radar and stepped-frequency radar,and the better anti-interference ability of pseudo-random coded radar is verified.An ISAR high resolution imaging processing method based on pseudo-random coded signals is also proposed.The imaging results demonstrate the effectiveness of the high-resolution imaging processing method,reflect the potential advantages of the phase-encoded signal ISAR imaging system,and lay a theoretical foundation for military anti-electronic reconnaissance and interference,target early warning detection and threat target tracking identification.This paper mainly introduces the key imaging technologies of pseudo-random code radar through the following parts:The first part briefly introduces the research background and basic principles of phase-encoding radar imaging technology,including high-frequency region target scattering center classification and radar echo signal modeling method,ISAR imaging principle,signal sparse representation method and basic principle of compressed sensing.The second part presents the knowledge of pseudo-random coded radar signal processing,including the concept and nature of pseudo-random coding.On this basis,the one-dimensional echo expression of pseudo-random coded radar is derived,and the imaging processing method is given.The simulation of the example is obtained and the one-dimensional radar image result is obtained.Then the influence of feature entropy-based feature selection method on the correct rate of one-dimensional range image recognition of pseudo-random coded radar is introduced.The simulation results show that the method can improve the accuracy of target recognition.Finally,based on the one-dimensional echo expression of pseudo-random coded radar,the two-dimensional echo model is derived,the imaging processing method is given,and the simulation of the example is carried out.Compared with the imaging effect of the step-frequency radar,the pseudo-random coded radar is better.The imaging results of the pseudo-random coded radar have better anti-interference ability.The third part consists of the pseudo-random code radar high-resolution imaging technology based on signal sparse representation and data fusion method.Firstly,the principle of Bayesian compressed sensing algorithm is introduced.Then,the one-dimensional and two-dimensional radar scattering sparse representation models based on pseudo-random coded signals are derived,and the signal amplitude phase compensation method is proposed.The multi-radar data fusion idea is introduced into pseudo-random code radar.In the imaging,the signal frequency band and the range of the viewing angle are broadened.Finally,the simulation of the example is carried out.The simulation results show that the range and azimuth resolution of the radar image are improved,and the effectiveness of the high resolution technique is verified.