Decoding method for selected call signals of segment handling airborne selective calling system

Abstract

The invention provides a decoding method for selected call signals of a segment handling airborne selective calling system. The decoding method is small in calculated quantity, precise in estimated value and capable of reducing erroneous judgment and missed judgment probabilities. According to the technical scheme, the method includes the steps that a signal acquisition module carries out windowing modulation on acquired single-frame signals through a signal preprocessing module, framing processing is conducted on the selected call signals, a power spectrum of each single-frame signal and a power spectrum of each windowing modulation signal are estimated by means of a periodogram method through a power spectrum estimation module, and coarse estimated values are obtained; frequency power spectrum estimated values and amplitude estimated values nearby the reference frequency of the selected call signals are corrected through an energy center correction module according to estimated results to obtain high-precision frequency estimated values and high-precision amplitude estimated values, a state judgment module synthesizes frame results and conducts state judgment through the precise estimated values, a skip module synthesizes judgment results of frames through a decoding state machine, and accordingly the whole decoding process is completed.

Description

technical field [0001] The invention relates to a decoding method for an airborne selective calling system. Background technique [0002] The airborne selective call system is a system used for point-to-point communication between the ground tower and the designated aircraft through the short-wave radio or ultra-short-wave radio. When the ground staff needs to call a specific aircraft, select the selective call code of the aircraft to be called through the coding panel, and the encoder generates an analog selective call signal in a specific format according to the set selective call code, and sends the The signal is sent to the aircraft in the airspace. All aircraft in the airspace decode the signal, and compare the decoding result with its own inherent code. If they are the same, they will output light and sound prompts through the warning panel to remind the pilot to listen, otherwise they will not respond. The selective call signal consists of 2 tone pulses, each pulse ...

AI Technical Summary

Problems solved by technology

[0005] 1. The implementation method based on the time-domain filter bank has strict requirements on the filter bandwidth, and high-order filters need to be used, which has a large amount of calculation and is not conducive to engineering implementation;

[0006] 2. The implementation method based on frequency-domain Fourier transform is limited by the frequency resolution, so it is impossible to accurately judge the frequency component of the signal, and it is prone to missed and wrong judgments;

[0007] 3. Due to the long duration of the selective call signal, the implementation method based on frequency domain Fourier transform cannot process the selective call signal at one time

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