Research On Amplitude/Phase Errors Calibration For Array Imaging Radar

The array imaging radar system is a multi-channel radar system,when it is used for imaging processing,can obtain superior performance compared with single-channel radar system.However,in practical applications,the material properties,assembly process,transmission line length,and array element parameters used in the multiple channels of the array imaging radar system,that cannot be completely consistent.Inevitably,there is a problem of amplitude and phase mismatch between multiple channels of the array imaging radar system.It mainly affects the imaging performance and image quality of radars.For a long time this problem has become a bottleneck in the theoretical high-quality imaging of array imaging radar systems.In the thesis,the amplitude and phase errors between multiple channels of the array imaging radar were studied to solve some practical problems.The main research work includes:Firstly,for the complex source of amplitude and phase errors in array imaging radar systems,the main sources of amplitude and phase errors in array imaging radar systems are analyzed.According to different sources of error,they are divided into inconsistent characteristics of transmission channels and inconsistent array element characteristics.The array imaging signal model including amplitude and phase errors is used to analyze the effects of amplitude and phase errors with imaging quality and imaging performance through theoretical and simulation.Secondly,based on the technology of FPGA-TDC high-precision time measurement,a new amplitude and phase error correction method is studied for the problem of amplitude and phase errors caused by inconsistent transmission channel characteristics.The method can use FPGA-TDC to realize the principle of high-precision time interval measurement and build a high-precision delay measurement platform,which avoids the need for multiple calibration problems in traditional measurement methods,and provides an internal calibration for array imaging radar system error estimation.The method was verified by theoretical analysis and simulation experiments.Finally,aiming the problem of amplitude and phase errors caused by inconsistent array element characteristics,the method of amplitude-phase error correction based on multiple prominent point like targets was studied.This method estimates the amplitude-phase error by analyzing and processing the echo data,and uses the estimated data to compensate for the error of the echo signal.Considering the problem of the phase history space variation of the target in the actual large-observation scene imaging,this method improves the problem that the precision of amplitude and phase error correction of single prominent point like target in large-scale observation scene is not high.Theoretical analysis and simulation experiments verify the effectiveness of the error correction method.