Design And Implementation Of Radar Polarimetry Target Modulation Simulator

The focus of the paper is to correlate the polarized radar target simulator, based on radar technology and polarization modulation system simulation technology. The aim has been to simulate the radar target echo signal and radar background information, to greatly apply in the early development stage. This approach has reduced the risk of design to a large extent, which has provided a platform with performance verification of radar in late. The polarized radar target modulation simulation technology has been obtained through various stages, considering preliminary study, medium-term debugging and later usage. Depending on polarized radar project of a department in China Aerospace Science and Industry Corporation(CASIC), this paper designs polarized radar target modulation simulator based on FPGA.Firstly, in this paper according to a mathematical model of radar target echo simulation, it is described how to explicitly analyze implementation methods of target echo signal simulation on the basis of radar distance equations, including target echo amplitude, target distance delay, Doppler frequency shift generated by target movement speed, polarization characteristic under different scattering coefficient generated by different target and so on. Meanwhile, it is by theory and project practice that we analyze deception jamming simulation methods, for instance, distance pull off, speed pull off, and Doppler flash.Secondly, a simulator is designed based on digital radio frequency memory technology base band algorithm processing platform and on CPCI standard bus system framework, consisting of a microwave down/up conversion link unit, a base-bank digital signal processing algorithm unit and a computer control unit based on PCI bus. On the basis of parallel processing capability and high-speed operational capability of FPGA, modeled system tool of System Generator, digital orthogonal mixing, filtering, decimation, simulated Doppler, echo delay modulation, digital up conversion, interpolation filtering and IQ modulation are the signal progressing key modules that are designed and realized in this project. In addition, digital memory board, based on FPGA, is used to preserve target echo information and radar polarization information. Digital memory board can take advantage of echo data to filed test, radar launch signal, to produce radio frequency echo signal with filed test information by correlation progressing, adding interference signal to echo signal used in related test of diamond. At the same time, the large capacity memory board is designed to save polarized angle information, and completes playback of different radar polarized angles with different commands of radar console.Finally, by debugging system key interfaces, signal source, spectrum analyzer, and oscilloscope relating to radar, simulator functions and indicators are tested and analyzed. The test results show that the design scheme is feasible, and achieves expected target.