A Decoding Method of Secondary Response Data Chain Based on Frame Clipping

Abstract

The invention discloses a frame-rejected secondary response data chain decoding method. The method comprises the following steps of: 1) determining a first response data link frame in video data, andsetting it as a leading edge response data link; 2) detecting, extracting and cutting the leading edge response data chain from the video data; 3) decoding and outputting the leading edge response data chain; 4) replacing the original video data by the remaining video data, and repeating steps 1) to 3) until the decoding and outputting of all the response data link are completed. According to theframe-rejected secondary response data chain decoding method, the complicated logic calculation caused by simultaneous comparison of multiple response data is eliminated by using the pulse amplitude characteristic and the time distribution characteristic of the response data, the logic judgment complexity of the multiple interleaving response decoding is reduced by adopting the loop iterative decoding method, and the front edge response data is cut to eliminate the interference on subsequent response data judgment, and reduce the dependence of the decoding calculation on the response data frame.

Description

technical field [0001] The invention relates to a frame clipping secondary response data chain decoding method. Background technique [0002] The secondary radar system is one of the key surveillance and communication means in the current air traffic control system. A typical secondary radar system consists of two parts, the ground station and the airborne response equipment. The secondary radar interrogator sends out interrogation pulses (using a frequency of 1030MHz) in all directions through the radar antenna. After the aircraft receives the interrogation pulses, it is installed on the The transponder on the aircraft responds to the response pulse (using a frequency of 1090MHz), and the interrogator receives and processes the response signal, and can obtain information such as the code, altitude, distance, and azimuth of the target. Among them, the composition rule of A / C mode reply data chain is: F1, F2 are frame pulses, which always exist in each reply, marking this se...

AI Technical Summary

Problems solved by technology

In high-density flight airspace, when the secondary radar sends an inquiry, it will inevitably receive response signals from multiple flying targets in the same sector. overlap), the existence of interleaving interference distorts the pulse width of the video pulse output by the receiver, the number of frame phantoms increases and the composition is complex, and the aliasing of the response data chains increases the difficulty of secondary radar decoding and even produces errors or cannot be decoded

[0004] The existing conventional decoding method for response data is a sliding window decoding method, but the conventional sliding window decoding method has the following deficiencies in high-density inquiry response applications: 1) The traditional sliding window decoding method is complex in logic, and requires video The rising edge and pulse width of each pulse in the data are repeatedly compared and judged. As the number of response data chains in a frame of video data increases, the efficiency of this method is low; 2) The traditional sliding window decoding method relies too much on the The first and last pulse code positions, in multiple interleaving, in order to ensure the correct reliability of decoding, all possible responses interleaved in the middle will be removed, and the first and last response frames will be retained, which is not applicable For surveillance applications in high-density airspace

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