Analysis Of Complex Signal Based On Ambiguity Function

In radar signal processing,the location of the target or radiation source has always been a hot issue.The application of time-frequency analysis method in array signal processing has a broad application prospect,Because of the advantages of ambiguity functions in dealing with noise compared to other time-frequency analysis methods,so the combination of ambiguity function and array signal processing method for target or radiation source positioning research has important research significance.As a new type of radar array,the beam pointing of Frequency diverse array(FDA)radar is rangedependented.It is of great significance to study the ambiguity function of the FDA radar and its positioning method in the target or radiation source.Therefore,this thesis mainly makes the following works based on the frequency control array and ambiguity function:(1)The basic meaning and basic properties of the ambiguity function are given.the ambiguity function of common signals are simulated and analyzed.Then the basic concepts and knowledge of the FDA radar are introduced.The difference of beam pointing between the traditional phased array radar and FDA are analyzed.At last,its application prospects are pointed out.(2)The signal model of the radar ambiguity function is deduced in this thesis.Firstly,the ambiguity function of the phased array radar are deduced,and its mathematical model are given.The ambiguity function of the common signal emitted by the phased array radar is simulated and verified.Then,based on the above,the ambiguity function model of the FDA radar is deduced,and its basic properties are derived and proved it from the mathematical point of view.The ambiguity function of the basic signal transmitted by the FDA radar is also simulated.Then the difference of the ambiguity function between and the phased array radar and FDA radar are analyzed.(3)The application of ambiguity function in FDA radar positioning is discussed,firstly,the mathematical model of phased array Multiple-Input Multiple-Output(MIMO)radar is given and based on this,the FDA-MIMO radar signal model is derived,the classical Multiple Signal classification(MUSIC)algorithm and its principles is introduced,and the mathematical proof is given for the application of time-frequency analysis in array signal processing.On this basis,the MUSIC algorithm based on ambiguity function is simulated and verified.Combined with FDA-MIMO radar,ambiguity function and MUSIC algorithm,a FDA-MIMO radar target location method based on ambiguity function and MUSIC algorithm is proposed.From the simulation experiment,the accuracy of the target angle and distance estimation can be improved at low SNR.Then the principle of Estimating Signal Parameter via Rotational Invariance Techniques(ESPRIT)algorithm is introduced.Based on FDA-MIMO,ESPRIT algorithm and ambiguity function,a FDA-MIMO target location method based on ambiguity function and ESPRIT algorithm is proposed.From the simulation experiment,the accuracy of the target angle and distance estimation can be improved at low SNR.