Non-cooperative BPSK signal decoding method with polarity judgment operation

Abstract

The invention discloses a non-cooperation BPSK signal decoding method with a polarity judgment operation. The method includes the following steps that (1) a digital medium-frequency channelized receiver detects and receives a BPSK signal; (2) residual carrier frequency of the detected and received BPSK signal is measured roughly; (3) after direct components are filtered out on the basis of square frequency doubling after rough measurement, frequency refining is achieved through CZT frequency measurement, and the residual carrier frequency is calculated; (4) the polarity judgment operation is carried out on the basis that the sequences are combined; (5) code checking is carried out again on the result of the step (4). The method is more suitable for decoding of the BPSK signal in a signal environment with a low signal to noise ratio, the calculation result is more reliable, and calculation complexity is greatly reduced.

Description

technical field [0001] The present invention belongs to the field of signal processing in electronic intelligence reconnaissance (ELectronic INTelligence, ELINT) system, and is used for decoding non-cooperative binary phase coding (Binary Phase Shift Keying, BPSK) signals, and is a solution to the traditional "frequency measurement-code detection - Deciphering Coded Sequences" decoding technique improvements. Background technique [0002] The ELINT system's processing of non-cooperative signals includes two aspects: identification of modulation mode and estimation of modulation parameters, both of which must be based on the successful detection of signals by the front-end receiver. The channelized receiver divides the reconnaissance bandwidth into several sub-frequency bands through multiple mixers with different local oscillator frequencies, so as to realize the reconnaissance of all-band signals. Each channel is equivalent to a superheterodyne receiver, which is transform...

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Problems solved by technology

[0015] (2) The amount of calculation for code detection based on wavelet transform is astonishing, and good results can only be achieved in a signal environment far greater than 0dB, which is quite different from the actual situation;

[0016] (3) Code detection first and then decoding based on sampling discrimination will produce the problem of cumulative error-even if the symbol period is detected, but as long as there is a small error in the symbol period, the error will continue to accumulate as the sequence length increases. causes fundamental errors in decoding

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