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A high-precision detection method for orbital frequency-shifted signals with low SNR based on sparse decomposition

A low signal-to-noise ratio, sparse decomposition technology, applied in frequency measurement devices and other directions, can solve the problems of decoding speed influence, large low-frequency error, and lack of high-precision detection capabilities for low-frequency parameters of carrier frequency.

Inactive Publication Date: 2016-11-30
CHINA RAILWAYS CORPORATION +1
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0009] The above-mentioned detection algorithm based on wavelet or frequency-domain spectral peak search can realize the detection and decoding of the carrier frequency and low frequency of the orbital frequency shift signal with high SNR, but it will fail at low SNR
In addition, the wavelet-based detection algorithm calculates the low-frequency error and low precision based on the duration of the upper and lower frequency bands, and the carrier frequency low-frequency detection accuracy based on frequency-domain spectral peak search is limited by the sampling rate and sampling time.
For low signal-to-noise ratio orbital frequency shift signals, although the above-mentioned method based on Duffing oscillator can realize low-frequency decoding of low signal-to-noise ratio carrier frequency, its decoding principle determines that this method does not have the high-precision detection capability of carrier frequency low-frequency parameters
In addition, the parallel structure of the Duffing oscillator array is convenient for hardware implementation, but the decoding speed will be greatly affected by software implementation.

Method used

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  • A high-precision detection method for orbital frequency-shifted signals with low SNR based on sparse decomposition
  • A high-precision detection method for orbital frequency-shifted signals with low SNR based on sparse decomposition
  • A high-precision detection method for orbital frequency-shifted signals with low SNR based on sparse decomposition

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Experimental program
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Embodiment 1

[0042] In this embodiment, the simulation generates the ZPW-2000 orbit frequency shift signal s(t), the amplitude of s(t) is A=1, and the carrier frequency f c =1701Hz, low frequency f d =10.4Hz, sampling frequency f s =6000, data length N=8192. The local waveform of s(t) is as figure 2 (a) is shown in the sub-picture, 2(b) is the local waveform after s(t) is superimposed with -10dB Gaussian white noise, and the 2(c) is the local waveform after s(t) is superimposed with -10dB Gaussian noise Partial waveform diagram. The color noise in this experiment is obtained by passing white noise with a variance of 1 through a fourth-order band-pass filter. The transfer function of the filter is:

[0043] H ( z ) = 0.0201 * ( 1 - 2 z - 1 + z 4 ) 1 - 1.637 z - 1 + 2.237 z - 2 - 1.3072 z - 3

[0044] Among them, the normalized upper and lower cutoff frequencies of the filter are 0.2Hz a...

Embodiment 2

[0053] The frequency parameters of the ZPW-2000 track frequency shift signal are respectively selected as 8 nominal carrier frequencies and 18 nominal low frequencies, and a total of 8*18=144 track frequency shift signals are generated. Other experimental conditions and operating methods are the same as Experiment 1. Under SNR=-10dB Gaussian colored noise, the carrier frequency and low frequency of these 144 kinds of track frequency shift signals were tested, and satisfactory results were obtained. Table 3 shows part of the detection results of the nominal carrier frequency detection, and Table 4 shows part of the detection results of the nominal low frequency detection.

[0054] Table 3 Nominal carrier frequency detection results under nominal low frequency (Gaussian colored noise SNR=-10dB)

[0055]

[0056] Table 4 Nominal low frequency detection results at nominal carrier frequency (Gaussian colored noise SNR=-10dB)

[0057]

[0058] Table 3 and Table 4 show that under the Gauss...

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Abstract

The invention discloses a high-precision detection method for orbital frequency shift signals with low signal-to-noise ratio based on sparse decomposition. First construct the first atomic library D according to the nominal frequency parameters of the orbital frequency shift signal 1 , and then use the matching pursuit algorithm to complete the coarse-grained detection of the carrier frequency and low frequency of the orbital frequency shift signal in the atomic library, and finally use the coarse-grained detected carrier frequency and low frequency atomic pool D 2 , and again using the matching pursuit algorithm in D 2 The best atoms are screened out to realize fine-grained detection of ZPW‑2000 orbital frequency shift signal carrier frequency and low frequency detection. The invention has controllable detection accuracy, good real-time performance and easy software implementation, and can perform high-precision detection of ZPW-2000 and UM-71 track frequency shift signals under low signal-to-noise ratio conditions, and can be used for the detection of railway locomotive signals , Decoding and track frequency shifting transceiver testing and quality inspection and other occasions.

Description

Technical field [0001] The invention relates to a low signal-to-noise ratio ZPW-2000 track frequency shift signal detection method, in particular to a high-precision detection method of low signal-to-noise ratio ZPW-2000 track frequency shift signal based on sparse decomposition, which can be used for strong noise Circumstances such as the detection and decoding of locomotive signals on general railways, passenger trains and high-speed railways, and the testing and quality inspection of track frequency shift transceivers. Background technique [0002] Frequency shift track circuit is an important basic equipment for railway signals. It connects train operation with signal display, etc., and is used to monitor the occupancy of the line. That is, the frequency shift signal is sent along the track through the transmitter, and the front track is transmitted to the receiver and locomotive. Occupy status information and train operation control information to ensure train operation safe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01R23/02
Inventor 王小敏郭进轩春霞闫连山潘炜杨扬
Owner CHINA RAILWAYS CORPORATION