The Approach Of Channel Equilibration To Frequency Diverse Array Radar

The Frequency Diverse Array(FDA)radar's is a new radar system which introduces a small difference among the carrier frequencies of transmitting elements leading to a range-angle-time-dependent transmit beam pattern.This feature brings new freedom in information and signal processing,and provides new ideas for anti-blur,anti-interference and target detection.However,in the actual frequency diverse array radar system,there must be errors in the channel which will affect the radar's receiving and transmitting characteristics and signal processing performance.So it is very significant to study the channel correction method of frequency diverse array radar.Aiming at the problem that the deterioration of the frequency diverse array's receiving and transmitting characteristics caused by the channel error,this paper conducts research on the channel correction method of frequency diverse array radar.The main work can be summarized as follows:1.Study the effect of channel errors on the transmitting and receiving characteristics of frequency diverse array radar.Firstly,the basic concept of frequency diverse array radar is given and the signal model is established.Secondly,the pattern characteristics of frequency diverse array are studied when the signal model is continuous signal and pulse signal.Thirdly,we introduce the frequency diverse array model containing channel errors and derive the transmit pattern and transmit-receive pattern formulas with channel errors,and analyze the effect of channel errors on the transmitting and receiving characteristics by simulation.Finally,it is concluded that the channel error causes the secondary lobe of pattern to increase,the ratio of main and secondary lobe to decrease,and the beam direction deviation.2.Aiming at the problem that the channel errors lead to the decrease of the ratio of the main lobe to the secondary lobe of the frequency diverse array radar pattern and the deviation of the beam direction,a broadband frequency-domain channel correction method is proposed by selecting the average channel as the reference channel.Firstly,we introduce the application scenarios of wideband channel correction and narrowband channel correction methods.Secondly,narrowband channel correction method is introduced.Thirdly,we introduce three channel mismatch models.And then the broadband channel correction method is introduced in detail.On the basis of the calibration performance evaluation standard,the validity of the methods is verified by simulation.Finally,the common reference channel selection method in the broadband frequency-domain channel calibration method is analyzed,and a multi-channel frequency-domain calibration method with the average channel as the reference channel is proposed.The simulation results show that it has better correction performance.3.Aiming at the requirement of channel correction of frequency diverse array radar,a channel correction scheme is proposed.Firstly,the factors influencing the performance of the wideband channel correction method are analyzed and the influences of the signal-to-noise ratio of the correction signal,the order of equalization filter and the time-bandwidth product on the performance are quantitatively analyzed.Secondly,the common digital up-conversion and digital down-conversion technologies in radar system are introduced.Finally,according to the results of the multi factor quantitative evaluation and the constraints of the engineering prototype of the frequency diversity array,the channel correction scheme of the frequency diversity array is formed,and the system indexes involved in the correction scheme are designed.The feasibility of the scheme is verified by simulation.4.Based on the multi-channel signal receiving subsystem,we complete the design and implementation of the channel correction module.Firstly,the overall framework of the frequency diversity array test system is briefly introduced.Secondly,the hardware architecture and module functions of the multi-channel signal receiving subsystem are introduced in detail.Thirdly,the channel correction module of the multi-channel signal receiving subsystem is designed.Finally,the channel correction of the frequency diversity array is completed to make the channel frequency response correction consistent.At the same time,it is verified that the wideband frequency domain correction method with the average channel selected as the reference channel has superior performance by the measured data.This thesis gradually extended theoretical analysis and simulation verification into the development and application of the experimental system.The theoretical study of the effect of channel errors on the transmitting and receiving characteristics of the frequency diverse array provides a basis for further research.The proposed channel correction method and array channel correction scheme are of great significance.