Study On Moving Target Detection Algorithms In Wideband Radar

With the rapid changes in science and technology,wideband radar and related products have become more and more widely used in military and life.Compared to classical radars,there are many advantages of wideband radars,which is more conducive to the target classification,target identification and other related processing.However,its high resolution characteristics could make the point target model in narrow-band radar no longer applicable,the radial movement of the target could cause signal migration through resolution cells during two adjacent pulses,and the echoes migration will make the coherent accumulation method applied to the narrow-band radar no longer applicable.Therefore,under the condition that the prior information is unknown,how to correct the distance migration between multiple pulses become one of the primary difficulties for wideband radars to target detection,classification and identification.Combined with the research background of this topic and the existing research results at the present stage,this paper has carried out the following researches on the several problems of maneuvering target detection in wideband radar:1.Based on the high-resolution characteristics of wide-band radar,extended target and its multiple scattering point models,the causes of distance migration and its influence were studied.Taking the linear frequency modulation(LFM)signal as an example,the echo models corresponding to the single-pulse and multi-pulse cases were simply deduced.In addition,the radar equation,the definition of SNR,and the influences of target translation and rotation on the echo signals in wideband radar were also introduced in this paper.This would pave the way for follow-up target detection.2.A detection method for moving targets coherent integration(MTCI)based on spline interpolation was studied.Firstly,the principle of MTCI and the method of correcting distance migration were introduced,and the problem of this algorithm which is the detection performance will decline when the spanning unit of target is a non-integer during two adjacent pulses was briefly explained.Next,through four interpolation algorithm's error analysis of various functions,spline interpolation was finally selected for subsequent processing.Immediately after,combining the advantages of MTCI algorithm and its existing problems,a new MTCI detection algorithm based on spline interpolation was studied.The performance of the new method to various targets was verified through simulation analysis.At the same time,through the comparison of the detection performance of the MTCI algorithm and the new algorithm for targets which spanning unit is a non-integer during two adjacent pulses,the effectiveness of the new algorithm was verified.3.A target detection method based on Keystone transform for bidirectional Doppler frequency shift was researched.Firstly,the principle of Keystone-transform,the “half-blind” effect,and the relationship between the Doppler fuzzy coefficient and its amplitude factor were introduced.Then,the method for long-time coherent integration in view of Keystone-transform was introduced.This method could effectively detect all targets with all velocity,but it has a large amount of calculation and is not suitable for engineering applications.Next,combined with Original algorithm and its inadequacies,a new target detection algorithm based on Keystone transform for bidirectional Doppler frequency shift was proposed.The effectiveness of the new method to targets was verified by analysis simulation.By comparing the performance and computational complexity of the two algorithms,it could be seen that the new algorithm greatly reduces the amount of computation and is suitable for engineering applications on the premise of ensuring correctness and no performance loss.