Key Technologies Research On Radar Echo Data Acquisition And Real-time Processing Of Space Objects

As human activity increases,the environment has become more and more complex.It is an urgent need to improve the ability to detect and identify space targets.The data acquisition system provides a way to obtain spatial target data.Its performance determines the accuracy and imaging resolution of the space target monitoring system.Based on the actual project,this paper studies the basic theory and practical method of data acquisition and designs a data acquisition system for alternate reception of wideband echo and narrowband echo.This dissertation can be divided into two parts: the design of wideband and narrowband alternate data acquisition scheme as well as the design and appliance of the FPGA software.When designing the data acquisition system,the system requirements and the wideband and narrowband alternating characteristic of radar pulse emitted by the transmitting station were taken into account.Therefore,the functions of the wideband data acquisition module and the narrowband data real-time processing module are reasonably designed and divided.Wideband signals and narrowband signals are sampled via wideband rate,and then processed separately according to the signal mode.The wideband data acquisition module is implemented for the wideband data acquisition,transmission,and storage.The narrowband real-time processing module is implemented for digital down conversion,polyphase filtering,and pulse compression of narrowband echo signals.Since oversampling results in high data rates for narrow-band signals,real-time processing inside the FPGA is not possible,therefore,a two-stage decimation filter is designed to effectively reduce the signal rate,and conduct a simulation analysis on its own performance.In the part of FPGA software design and implementation,FPGA software design of wideband acquisition module and narrowband data processing module is introduced,and the hardware resources consumed are analyzed.Finally,according to the specific needs of the project,the hardware test platform was built using the chassis and VPX-D5000 data acquisition board.The result verifies the function of the wideband data acquisition module and the synchronization performance of the data acquisition system.It also verifies the functions of the digital down-converter module,the polyphase filter module and the pulse compression module in the narrow-band data real-time processing system.The test results show that the designed wideband data acquisition module can realize real-time sampling of 4GSPS with phase stability of 0.004 radians and the time difference between two ADCs is 13.29 ps,which can meet the requirements of the project.The designed narrow-band data processing module can achieve real-time processing of narrow-band signals under bistatic radar wide and narrow alternating pulse mode through digital down-conversion,multi-phase filtering and pulse compression.