Research On Imaging Processing Method Of Circular Aperture Micro-Deformation Monitoring Radar

Circular aperture radar for micro-deformation monitoring has overcome the limitations of conventional linear aperture radar with a single observation angle,enabling all-weather,high-resolution,and omni-directional observations of the surrounding area.Unlike radar systems that use linear apertures,the target phase history variations in circular aperture radar are not only influenced by azimuth angles but also by the topography of the observed area.In regions with significant terrain variations,severe spatial phase distortions occur in the radar images obtained from circular aperture radar.Existing imaging processing methods employ fixed reference planes or slant ranges for two-dimensional imaging,neglecting the phase distortions caused by terrain changes.Consequently,the imaging quality is poor or even impossible.Therefore,this paper focuses on the research of high-precision imaging algorithms for circular aperture radar in micro-deformation monitoring.The main contents are as follows:1.The paper studies the imaging mode of a single-base circular aperture radar,introduces the geometric and echo models of circular aperture imaging,presents the sampling criteria and performance indicators for circular synthetic aperture radar,and proposes a new imaging mode for dual-base circular aperture radar,establishing an inversion model for elevation information.2.To address the challenge of extracting target area elevation with conventional singleangle radar,a method based on dual-base radar is proposed for extracting target area elevation.This method establishes spatial connections between the radar images obtained from different photographic angles for the same target point using two base radars.By improving the distance-Doppler equation in relative orientation,the relative position of the target is solved,and the elevation of the observation area is obtained.The correctness and effectiveness of this method are verified through simulation experiments.3.In response to the issue of degraded imaging quality or even impossible imaging in regions with significant terrain variations using existing circular synthetic aperture imaging algorithms,the influence of pitch angles on the imaging quality of circular aperture radar is quantitatively analyzed.A new circular synthetic aperture algorithm is proposed by introducing elevation information of the observed area.Based on the division of imaging space according to pitch angles,a phase distortion compensation function considering spatial phase distortions caused by terrain variations is constructed.The effectiveness and correctness of this method are verified through simulation experiments.