Study On Wide-swath Millimeter Wave Imaging And Positioning Method For Terminal Guidance

Millimeter wave radar is widely used in precision guided weapon system because of its good resolution and anti-jamming performance.It can realize the rapid and accurate attack on strategic targets by using the key technologies such as imaging detection and missile positioning.However,severe atmospheric attenuation restricts the detection range of millimeter wave radar,making millimeter wave radar commonly used in the terminal guidance stage.The research on millimeter wave wide-swath imaging and positioning methods for the terminal guidance section can effectively improve the performance of precision guided weapons,and has great research value and military significance for future operations.This paper focuses on the non-uniform dive motion characteristics of the terminal guidance stage,combined with the high real-time wide-swath imaging detection and high-precision positioning requirements,and studies the key issues in the millimeter wave wide-swath imaging and positioning of the terminal guidance stage.The main contents of the thesis are as follows:Firstly,aiming at the mutual restriction of range,resolution and imaging parameter design caused by limited space resources of missile,this paper presents the design methods of imaging parameters such as radar operating frequency,transmitting signal bandwidth,signal duty ratio,pulse repetition frequency,pulse accumulation number and coherent accumulation time in terminal guidance,so as to make rational use of missile resources and improve missile performance.In addition,for large-scale scene imaging detection,which is much larger than the beam coverage,this paper designs two scanning strategies to perform full coverage scanning on the scene,and to record wide scene radar signal echoes.Secondly,for the imaging geometry model of non-uniform motion,this paper establishes the imaging configuration with acceleration,and deduces the mathematical model of echo signal.Also,it introduces a DBS imaging algorithm based on spectrum analysis.The imaging algorithm introduces envelope walking correction and quadratic phase error compensation into DBS imaging,and combines Doppler parameter estimation to obtain radar images with good focusing effect,which lays a foundation for the subsequent guidance process.In addition,for the severe geometric distortion caused by the slant range plane imaging,a fast geometric distortion correction and sub image stitching method is adopted in this paper to stitch each wave position image with serious geometric distortion to the ground plane.This method requires only a small amount of interpolation operations,and it can quickly acquire the widely undistorted ground image of the target scene.Finally,aiming at the problem that the traditional missile positioning method relies on the accuracy of the inertial navigation system,this paper introduces a tetrahedron missile positioning method.The tetrahedron is composed of the missile,the target point and the reference point along with the matching point arbitrarily selected which are on the ground plane.According to the geometric relationship of the tetrahedron,the three-dimensional coordinates of the missile relative to the target are calculated analytically.The three feature points on the ground plane are obtained by high-resolution SAR image matching.This method can avoid the problem of poor positioning accuracy caused by poor accuracy of inertial navigation system.This paper aims to study a millimeter wave wide-swath imaging and positioning method for the terminal guidance segment,which provides some basis for the development of precision guidance technology.