Design method of miniature synthetic aperture radar (SAR) digital down converter based on rapidly-moving finite impulse response (FIR) filter

Abstract

The invention discloses a design method of a miniature synthetic aperture radar (SAR) digital down converter based on a rapidly-moving finite impulse response (FIR) filter. The steps includes utilizing a parallel processing method to process eight input data in a clock period, enabling an internal clock of a field programmable gate array (FPGA) to run at 250 megahertz, enabling a sampling rate in the miniature SAR to reach 2 G sps, utilizing a miniature SAR parameter to optimize an implementation structure of the traditional digital down converter, designing two FIR filters from Q way parallel filters in the optimized structure according to a work frequency of 250 megahertz and coefficient of an odd member position of an existing low pass filter, optimizing the digital down converter of the rapidly moving FIR filter design and finally designing a miniature SAR digital processing hardware module which is used for processing data of the digital down converter. According to requirements of the miniature SAR, the design method of the SAR digital down converter based on the rapidly-moving FIR filter utilizes the FPGA to achieve the high-speed and direct digital down converter module, takes high sampling rate in account, optimizes and screens out an optimal structure and improves digitization degree and performance of radar.

Description

technical field [0001] The invention relates to the field of radar device design, in particular to a design method of a digital down-converter for radar signals, in particular to a design method for a micro-SAR digital down-converter based on a fast-moving FIR filter, which is used for radar with a very high sampling frequency The signal is digitally down-converted. Background technique [0002] Modern warfare requires an instant grasp of the situation on the battlefield. Synthetic Aperture Radar (SAR) can obtain high-resolution images of the ground, and is affected by various severe weather such as heavy fog, heavy rain, sandstorms and clouds, and is not affected by day and night. , has a large operating distance, can greatly improve the information acquisition ability of the radar, so it has become the main means of battlefield reconnaissance. The micro system will help reduce the space and load requirements of the carrier, and help increase the mobility, flexibility and ...

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to overcome the problems of low sampling rate, complex structure and difficult filter design in the prior art of digital down-conversion chips, and to provide a digital down-converter suitable for high sampling rate of micro-SAR signals The design method first optimizes the traditional implementation structure of the digital down-converter according to the characteristics of the micro-SAR signal parameters, and then provides two implementation structures of the FIR filter with a Q channel parallelism of 4 in the design, and selects one of the implementation structures to complete Design, thereby reducing the complexity of the system, improving the degree of digitization and performance of the entire radar, and finally designing the hardware structure of the digital processing part of the digital down-converter on this basis

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