Design And Implementation Of Frequency Diverse Array Radar Frequency Synthesis Subsystem

Frequency Diverse Array radar is a new type of radar that applies a small frequency offset to the transmission carrier frequency of adjacent array elements according to a certain rule.Because its beam pointing will deflect with the change of distance,it can effectively provide detection targets.The information of the distance dimension has become a hot issue studied by domestic and foreign researchers in recent years.Regarding the principle,mechanism and basic characteristics of Frequency Diverse Array radar,the understanding of researchers at home and abroad has long reached agreement,but the discussion on the application method of frequency offset and the frequency offset scheme has never stopped.This kind of transmission structure and transmission waveform,how to choose the type of frequency deviation and ensure the best effect has always been a concern of everyone.In response to these problems,this thesis carried out theoretical analysis,program research,design implementation,test verification,etc.The main contents are as follows:(1)A linear frequency modulation continuous waveform multi-channel coherent circuit structure that can be applied to Frequency Diverse Array radar is proposed.Through the combination of linear frequency modulation continuous waveform technology and direct digital frequency synthesis technology,the structure of direct digital frequency synthesis is optimized to solve the problem of multiple signals generated by a single direct digital frequency synthesis signal source,and the digitization of linear frequency modulation technology is realized.It effectively reduces the complexity of the circuit structure and improves the efficiency of multi-channel signal generation.(2)To meet the diverse needs of Frequency Diverse Array radar prototypes for frequency and phase.Field programmable gate array(Filed Programmable Gate Array,FPGA)circuit realizes the frequency switching of the frequency synthesis system,the switching of different functions of the Frequency Diverse Array radar and the phased array radar,and realizes the phase control of the signal source signal and the signal of each channel Phase modulation.(3)Complete the frequency deviation design of the Frequency Diverse Array radar prototype.By studying the relevant frequency offset design schemes,choosing the achievable frequency offset scheme suitable for the platform of this thesis,implementing the frequency offset control and switching of the circuit by the upper order,adding the logic of function switching,and writing according to the functions required by the Frequency Diverse Array radar system.The control command of the upper computer realizes the reconstruction of the circuit through the programmable logic device and realizes the normal work of the system.(4)Complete the performance test of the Frequency Diverse Array radar,and process and analyze the Frequency Diverse Array radar signal.Through the actual test in the outdoor field,the actual effect of the Frequency Diverse Array radar prototype is verified.This thesis finally verifies the basic characteristics of Frequency Diverse Array radar by analyzing the actual test data.