Research On Methods For Measuring Motion Parameters Of Flying Object Using Wideband 3-D Electromagnetic Scattering Model

Radar is the main equipment for the measurement of taget motion parameters,which has the adavantage of long working distance and high measurement precision.With the continuous development of wideband radar technology,radar image resolution continues to improve,and more motion parameters can be measured through utilizing the wideband radar.Therefore,the target motion parameter measurement based on wideband radar has great practical value.However,the target is no longer expressed as a point target in a wideband radar,but rather as a range-spread target,which makes the traditional narrowband radar-based measurement method no longer applicable.In addition,the radar instantaneous bandwidth is always limited,and the radar observation angle can only be within a limited range,therefore the radar is in the absence of the state of the target observation,which makes it difficult to use the radar to obtain the target attitude parameters.On the basis of the above analysis,this paper introduces the target three-dimensional electromagnetic scattering model into the wideband radar measurement based on deeply analyzing the radar radar echo model of the moving target,and studies the measurement of motion parameters based on the wideband three-dimensional electromagnetic scattering model.The main work and the main research results are as follows:1.A flying target motion parameter measurement framework based on wideband three-dimensional electromagnetic scattering model is proposed.The proposed framework solves the problem of mathematical modeling of the target electromagnetic scattering characteristic by introducing the target three-dimensional electromagnetic scattering model,which transforms the target motion parameter measurement problem into the parameter estimation problem.The measurement framework is a theoretical guide for our subsequent design of the measurement methods of the motion parameters,which includes the generation of flying target radar echo based on wideband three-dimensional electromagnetic scattering model,the detection method of high-speed flying target,and data matching strategy,etc.Based on this framework,we can design different radar echo data processing methods to carry out the target motion parameter measurement.In this measurement framework,a high-speed radar target detection method based on waveform contrast is proposed for wideband radar detection of high-speed moving targets.When the target is moving at high speed,the detection performance of the traditional broadband radar detection algorithm will be degraded.The essential reason is that the influence of the target velocity on the phase of the broadband radar echo will cause the broadband radar echo waveform to diverge and the signal to noise ratio will decrease.In order to solve the above problems,this paper chooses the waveform contrast as the detection statistic to carry out the detection of the broadband radar motion target.The method is divided into two steps: the first step is the motion compensation of the radar echo based on the waveform contrast.The second step is target detection,which uses the waveform contrast as the detection statistic.It can be seen from the above-mentioned detection process that the method is based on the waveform contrast of the high resolution range profile without the need of selecting different characteristics for motion compensation and target detection respectively,and thus its algorithm complexity is low.The experimental results show that the proposed method is superior to the traditional wideband radar target detection algorithm for high speed moving target detection.2.A flying target attitude estimation method based on wideband three-dimensional electromagnetic scattering model is proposed.At present,there are very few researches on radar target attitude measurement.The reason is that the radar is observing the target in the limited bandwidth and limited observation angle,that is,the target information obtained by the radar is missing dimension.In order to solve the problem of missing dimension in wideband radar attitude measurement,this paper uses the target three-dimensional electromagnetic scattering model to obtain the information directly related to the target attitude in the wideband radar echo.The incident direction of radar wave in the target coordinate system is the key to solve the target attitude.By combining the known direction of the radar wave in the radar coordinate system,the orientation vector of the direction vector in the two coordinate systems is used to solve the attitude of the target in the radar coordinate system.In the estimation of the incident direction of the radar wave in the target coordinate system,we use the three-dimensional electromagnetic scattering model to generate high-resolution distance images under different electromagnetic wave incidence directions and perform the feature matching with the target high resolution distance profile obtained by the radar.We put forward the corresponding feature matching method for the fully polarimetric radar and the unipolar broadband radar,respectively.According to the relationship between radar incident direction and target attitude,we design a target absolute attitude estimation method based on bistatic wideband radar,which can use the bistatic radar echo of single observation time to estimate the target attitude.The experimental results verify the effectiveness of the proposed method.3.An optimization method of flight target motion parameter estimation based on wideband radar echo signal is proposed.In this paper,a velocity optimization estimation method based on three-dimensional electromagnetic scattering model is proposed to solve the problem that the self-focusing process is "blind" and the velocity estimation accuracy is not high for the traditional speed estimation method based on high resolution distance profile.The basic principle of the proposed method is to obtain the optimal velocity estimation by matching the distance-compensated distance image with the non-shape distorted distance image produced by the three-dimensional electromagnetic scattering model.Aiming at the problem that the distance between the target geometric center and the radar can not be obtained in the traditional radar distance measurement,this paper proposes a distance estimation method based on three-dimensional electromagnetic scattering model.This method utilizes the prior information of the target geometric center position provided by the target three-dimensional electromagnetic scattering model,and the position of the target center on the measured high resolution distance image can be estimated according to the geometric center position of the model.Combined with the target parametric motion model,this paper presents a method of target attitude optimization based on a monostatic wideband radar.This method improves the measurement accuracy of the target attitude by jointly using the target echoes in a continuous period of observation time.