Research And Development Of Hardware System For Ground-based Interferometric Synthetic Aperture Radar

In recent years,disasters caused by broken bridges,collapsed buildings and unstable slopes have occurred frequently.Before the macro-displacement of bridges,buildings,tailings dams,mountain slopes,etc.occurs and breaks,collapses,and landslides,micro-deformation that is not within a reasonable range will occur.Therefore,fast,high-precision micro-deformation monitoring is a necessary measure to prevent these disasters.The GB-InSAR technology is an important means of micro-deformation monitoring,which can achieve all-weather,all-weather,fast and high-precision micro-deformation monitoring.In this paper,the GB-InSAR hardware system is studied.Through the design and development of the system’s transmitting front end,receiving front end,transceiver antenna and other modules,the GB-InSAR hardware system is built and experimentally verified.The main research contents are as follows:(1)The working principle of imaging and micro-deformation monitoring of GB-InSAR system is analyzed,the geometric monitoring model of GB-InSAR system is established,and the overall design scheme of GB-InSAR hardware system is proposed.The signal form of LFMCW is analyzed,and the reasons why the system has high resolution in range and azimuth directions and high deformation monitoring accuracy are discussed.The performance indexes of the GB-InSAR hardware system are analyzed,the key technical parameters of the hardware system are determined,and the rationality of the selection of the technical parameters of the hardware system is verified through simulation experiments.(2)The hardware circuit and FPGA program of the transmitting front end and receiving front end of the GB-InSAR hardware system are designed in detail,and the transceiver antenna is designed and simulated.The hardware circuits such as transmitting front end and receiving front end are designed in detail.The software is developed using Verilog HDL hardware description language.The transceiver antenna is designed and simulated using HFSS electromagnetic simulation software.(3)The PCB boards of GB-InSAR hardware system transmitting and receiving front-ends are designed and manufactured,and the hardware modules and the whole are tested.The design values and simulation and test results of the hardware system technical parameters are compared and analyzed,and the system design technology is reached indicators and requirements,the feasibility of system design has been proven.A 5 m long RF coaxial cable was used to simulate the point target,and the corresponding difference frequency signal was obtained at the test instrument end.A distance measurement experiment was carried out in the passageway of a building,and the distance of the metal indicator board with a distance of 23.8 m from the radar sensor was measured,and the distance measurement error was 0.6 m,which was in accordance with the system design index.With a metal cabinet measuring 0.5×0.5×0.8 m~3 as the target,it was translated by5 mm along the radar line of sight,and the phase change related to the 5 mm displacement was obtained.The hardware system’s ability to monitor millimeter-level micro-deformation was verified.