Method for extracting zero intermediate frequency secondary radar response pulses based on FPGA

Abstract

The invention discloses a method for extracting zero intermediate frequency secondary radar response pulses based on FPGA. The method comprises the following steps: obtaining initial parameters of a receiving channel, initializing a noise mean value to an initial noise mean value after the device is powered on, and calculating a noise positive bias threshold and a noise negative bias threshold ofthe receiving channel according to the initial parameters and the noise mean value; caching N groups of continuous input data, discriminating the cached N groups of input data, eliminating signal datafrom the input data and replacing the same with the noise mean value to obtain N groups of noise data, and averaging the N groups of noise data to obtain a current noise mean value; and comparing theinput data with the current noise mean value to obtain output data that is larger than the mean value, and performing narrow pulse filtering on the output data to obtain an extracted response pulse sequence. According to the method disclosed by the invention, by discriminating the type of the noise data and accurately extracting the noise data in the input data to obtain a dynamic noise threshold, the interference of abnormal noise data on back end decoding is reduced, and the reliability of a secondary radar device is improved.

Description

technical field [0001] The invention relates to the field of radar signal processing, in particular to an FPGA-based zero-IF secondary radar response pulse extraction method. Background technique [0002] The invention relates to data on a receiving channel of a secondary radar system which is formed by superposition of signals and noises. To complete the correct decoding of response pulses, it is necessary to filter out noises and extract useful signals. [0003] At present, the main way to extract the response pulse is to calculate a relatively reasonable noise threshold value according to the system noise characteristics in the equipment debugging / test stage, and discard the data lower than the threshold value as noise, and then narrow the processed data. Pulse filtering processing to extract useful signals. [0004] When the prior art is applied to different devices, there are certain differences in noise amplitudes caused by hardware differences and the like. When des...

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Problems solved by technology

[0005] In view of the above existing problems: 1) the problem that the same design cannot be automatically adapted to different platforms; 2) the baseband data has the problem of rising noise in the video data caused by DC bias, and provides a real-time update of the noise threshold. Zero-IF secondary radar response pulse extraction method to avoid the problem of rising noise floor in video data caused by DC bias in baseband data

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