Method for amplitude/phase correlation joint detection of response signal

Abstract

The invention provides a method for amplitude / phase correlation joint detection of a response signal, and aims to provide a method capable of effectively detecting a coded modulation pulse signal. Themethod can be realized through the following steps: performing digital down-conversion on three paths of intermediate frequency signals received by a sum channel, a difference channel and an omnidirectional channel in a signal processing module to a baseband, generating orthogonal sine and cosine signals by using a DDS in an FPGA, multiplying the sine and cosine signals by the intermediate frequency signals respectively, performing low-pass filtering to obtain an orthogonal I baseband signal and a Q baseband signal, respectively carrying out phase and amplitude correlation accumulation on thebaseband signals according to the information coding code words to form an aligned sum channel phase correlation peak and amplitude correlation peak, respectively carrying out fixed threshold judgment on the sum channel phase correlation peaks and carrying out self-adaptive threshold judgment processing on the amplitude correlation peaks to form a pulse binarization signal and a pulse effective signal , and performing single pulse processing and receiving discrimination inhibition processing to complete one-time detection of the target response pulse signal.

Description

technical field [0001] The invention is an interrogation machine of a secondary radar system, which adopts a target detection method of combined processing of amplitude and phase correlation to realize the detection of the secondary radar response pulse signal. More specifically, it is a target detection method that uses the amplitude correlation method and phase correlation method to jointly detect the pulse correlation peak of the response signal in the signal processing process of the interrogator, and uses the correlation peak amplitude to perform single pulse processing and receive sidelobe suppression. Background technique [0002] In radar target detection, the problem of large targets covering small targets is often encountered. Generally, the RCS of a large civil aviation airliner is more than one or two hundred square meters, and the RCS (Radar-CrossSection) of a small aircraft is between 1 and 2 meters. 2 between. If the distance between the two is very close, t...

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Problems solved by technology

When the system has different gain amplitudes for different frequency components of the input signal, and the relative phase shift also changes at the same time, the output waveform is distorted, and the amplitude and phase of the output response are distorted

There are two disadvantages of this method. One is that under the condition of low signal-to-noise such as sensitivity, false alarms or missing alarms may occur when only the phase method is used to detect or the amplitude is used alone to detect the correlation peak of the target response signal; the other is that when the signal modulation When the mode is non-constant-envelope modulation, the pulse amplitude of the baseband signal directly obtained is not constant, and the amplitude will decline greatly at the moment of symbol conversion, which will affect the accuracy of single-pulse processing and receiving sidelobe suppression processing. Spend

At present, there are no domestic reports and materials on the application of the method of amplitude and phase correlation joint processing for target detection in the secondary radar system interrogator

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