CN107689815A - A kind of MSK band spread receivers Adaptive Anti-jamming detection threshold determines method - Google Patents

Abstract

The invention discloses a method for determining an adaptive anti-interference detection threshold of an MSK spread spectrum receiver, which is realized by an A/D data buffer module, a window processing module, a time-frequency conversion module, an amplitude spectral line mean value determination module, and a detection threshold determination module . The A/D data cache module caches the A/D acquisition data of the spread spectrum signal; the windowing processing module performs windowing processing on the buffered data; the time-frequency transformation module performs time-frequency transformation on the data after windowing processing; the detection threshold The determination module determines the adaptive anti-jamming detection threshold. The invention solves the problem of poor adaptability of the traditional anti-jamming detection threshold determination method.

Description

A Method for Determination of Adaptive Anti-jamming Detection Threshold of MSK Spread Spectrum Receiver

technical field

The invention relates to a method for determining an anti-interference detection threshold, in particular to a method for determining an adaptive anti-interference detection threshold for an MSK spread spectrum receiver.

Background technique

The MSK spread spectrum receiver needs to despread the received spread spectrum signal to restore the original information. When the power of the narrowband interference signal is much greater than the power of the spread spectrum signal, only rely on the processing gain of the spread spectrum system to suppress the narrowband Interference is difficult to achieve good performance, so it is necessary to use anti-jamming methods to suppress narrow-band interference, and the determination of the anti-jamming detection threshold directly affects the anti-jamming capability of the spread spectrum receiver. The traditional determination method of anti-interference detection threshold adopts the method of fixed spectral line detection threshold, that is, selects a fixed spectral line detection threshold according to the measured value. This method is simple to implement, but poor in adaptability.

Contents of the invention

The purpose of the present invention is to provide a MSK spread spectrum receiver adaptive anti-interference detection threshold determination method to solve the problem of poor adaptability of the traditional anti-interference detection threshold determination method.

A MSK spread spectrum receiver adaptive anti-jamming detection threshold determination method, its specific steps are:

The first step is to build an adaptive anti-jamming detection threshold determination system

The adaptive anti-interference detection threshold determination system includes: A/D data cache module, window processing module, time-frequency conversion module, amplitude spectral line mean value determination module and detection threshold determination module; the function of the A/D data cache module To: perform buffer processing on the A/D acquisition data of the spread spectrum signal; the function of the windowing processing module is: perform windowing processing on the buffered data; the function of the time-frequency transformation module is: perform time-frequency processing on the data after windowing processing Transformation; the function of the detection threshold determination module is to determine the adaptive anti-jamming detection threshold. Run the above modules in the FPGA chip.

Step 2 The A/D data cache module caches the A/D acquisition data of the spread spectrum signal

A/D data buffer module generates sampling clock , under its control the A/D chip collects the spread spectrum signal, and the number of sampling points is , the A/D data cache module takes this samples , for caching.

sampling clock The selection principle: , is the pseudo code rate of the spread spectrum signal.

Step 3 The windowing processing module performs windowing processing on the cached data

The windowing processing module takes the data with the Hamming window function Doing the time-domain product operation, we get ;when When , the Hamming window function , other cases .

Step 4 Time-frequency transformation module performs time-frequency transformation on the windowed data

Time-frequency transformation module for data Perform a fast Fourier transform:

time domain data Transform to frequency domain data , , Index value for frequency domain points.

Step 5: The detection threshold determination module determines the adaptive anti-jamming detection threshold

The detection threshold determination module is used for frequency domain data Perform a modulo operation to obtain frequency domain data The magnitude spectrum of the Take the mean value of the amplitude spectrum lines to obtain the mean value of the amplitude spectrum lines ;using the formula: , get the adaptive anti-jamming detection threshold ,in is the minimum threshold value, and is the amplitude spectrum line of the signal without interference, which is obtained through theoretical calculation; is the attenuation coefficient, take .

So far, the MSK spread spectrum receiver adaptive anti-jamming detection threshold has been determined.

This method solves the problem of poor adaptability of the traditional anti-jamming detection threshold method, and the simulation verification proves the effectiveness and feasibility of this method in theory, and this method has been tested on the MSK spread spectrum receiver demonstration verification board , the test results show that this method can determine the adaptive anti-jamming detection threshold, and the determined adaptive anti-jamming detection threshold is accurate and meets the system requirements.

detailed description

A MSK spread spectrum receiver adaptive anti-jamming detection threshold determination method, its specific steps are:

The first step is to build an adaptive anti-jamming detection threshold determination system

The adaptive anti-interference detection threshold determination system includes: A/D data cache module, window processing module, time-frequency conversion module, amplitude spectral line mean value determination module and detection threshold determination module; the function of the A/D data cache module To: perform buffer processing on the A/D acquisition data of the spread spectrum signal; the function of the windowing processing module is: perform windowing processing on the buffered data; the function of the time-frequency transformation module is: perform time-frequency processing on the data after windowing processing Transformation; the function of the detection threshold determination module is to determine the adaptive anti-jamming detection threshold. Run the above modules in the FPGA chip.

Step 2 The A/D data cache module caches the A/D acquisition data of the spread spectrum signal

A/D data buffer module generates sampling clock , under its control the A/D chip collects the spread spectrum signal, and the number of sampling points is , the A/D data cache module takes this samples , for caching.

sampling clock The selection principle: , is the pseudo code rate of the spread spectrum signal.

Step 3 The windowing processing module performs windowing processing on the cached data

The windowing processing module takes the data with the Hamming window function Doing the time-domain product operation, we get ;when When , the Hamming window function , other cases .

Step 4 Time-frequency transformation module performs time-frequency transformation on the windowed data

Time-frequency transformation module for data Perform a fast Fourier transform:

time domain data Transform to frequency domain data , , Index value for frequency domain points.

Step 5: The detection threshold determination module determines the adaptive anti-jamming detection threshold

The detection threshold determination module is used for frequency domain data Perform a modulo operation to obtain frequency domain data The magnitude spectrum of the Take the mean value of the amplitude spectrum lines to obtain the mean value of the amplitude spectrum lines ;using the formula: , get the adaptive anti-jamming detection threshold ,in is the minimum threshold value, and is the amplitude spectrum line of the signal without interference, which can be obtained by theoretical calculation; is the attenuation coefficient, usually taken as .

Up to this point, the MSK spread spectrum receiver adaptive anti-jamming detection threshold has been determined.

Claims (1)

1. a kind of MSK band spread receivers Adaptive Anti-jamming detection threshold determines method, it is characterised in that concretely comprises the following steps：

The first step builds Adaptive Anti-jamming detection threshold and determines system

Adaptive Anti-jamming detection threshold determines system, including：A/D data cache modules, windowing processing module, time-frequency conversion mould Block, amplitude spectral line average determining module and detection threshold determining module；The function of the A/D data cache modules is：To spread spectrum The A/D gathered datas of signal carry out caching process；The function of windowing processing module is：To data cached carry out windowing process；When The function of frequency conversion module is：Time-frequency conversion is carried out to the data after windowing process；The function of detection threshold determining module is：It is right Adaptive Anti-jamming detection threshold is determined；Above-mentioned module is run in fpga chip；

Second step A/D data cache modules carry out caching process to the A/D gathered datas of spread-spectrum signal

A/D data cache modules produce sampling clock, at the control A/D chips spread-spectrum signal is acquired, sampled point Number is, A/D data cache modules by thisIndividual sampled value,Cached；

Sampling clockSelection principle：,For the pseudo- bit rate of spread-spectrum signal；

3rd step windowing processing module is to data cached carry out windowing process

Windowing processing module is dataWith Hamming window functionTime domain product calculation is done, is obtained；WhenWhen, Hamming window function, other situations；

4th step time-frequency conversion module carries out time-frequency conversion to the data after windowing process

Time-frequency conversion module is to dataCarry out FFT：

Time domain dataIt is transformed to frequency domain data,,For frequency domain points index value；

5th step detection threshold determining module is determined to Adaptive Anti-jamming detection threshold

Detection threshold determining module is to frequency domain dataModulo operation is carried out, obtains frequency domain dataAmplitude spectral line, It is rightIndividual amplitude spectral line, which takes, is worth to amplitude spectrum line average；Use formula：, obtain Adaptive Anti-jamming Detection threshold, whereinIt is minimum threshold value, is the amplitude spectral line of signal when not interfering with, is obtained by theoretical calculation；It is the coefficient of decay, takes；

So far MSK band spread receiver Adaptive Anti-jamming detection thresholds are determined.