Short-time Fourier transformation-based intra-pulse frequency coded signal parameter measurement method

A technology of short-time Fourier transform and coded signals, which is applied in measurement devices, pattern recognition in signals, and radio wave measurement systems, etc. It can solve problems such as small signal-to-noise ratio, signal distortion, and large noise floor fluctuations.

Active Publication Date: 2019-12-31
BEIJING INSTITUTE OF TECHNOLOGYGY
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Problems solved by technology

[0003] Under ideal conditions, accurate parameter measurement results can be obtained through instantaneous frequency measurement, time-frequency analysis, etc. Accurately measuring parameters of frequency-encoded signals is difficult

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  • Short-time Fourier transformation-based intra-pulse frequency coded signal parameter measurement method

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Embodiment Construction

[0029] The present invention will be described in detail below with reference to the accompanying drawings and examples.

[0030] The present invention provides a method for measuring parameters of intrapulse frequency coded signals based on short-time Fourier transform, the specific process is as follows figure 1 shown, including the following steps:

[0031] Step 1. Perform short-time Fourier transform (STFT) of the initial window length on the signal to be detected, calculate the length of a subcode according to the STFT result, and set the calculated length of the subcode as the window length for subsequent STFT processing.

[0032] In the embodiment of the present invention, in order to balance the time resolution and frequency resolution, the window length of short-time Fourier analysis is preferably designed as the symbol length. If the window length is too short, the frequency domain resolution will deteriorate, and within one subcode There is no change in frequency, ...

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Abstract

The invention discloses a short-time Fourier transformation-based intra-pulse frequency coded signal parameter measurement method and belongs to the technical field of radar signal reconnaissance. With the method adopted, parameter measurement can be performed on intra-pulse frequency coded signals under the conditions of intra-pulse fluctuation, strong interference and weak received signals in acomplex environment. The method specifically comprises the following steps that: short-time Fourier transformation (STFT) is carried out on to-be-detected signals; two-dimensional morphological filtering is carried out to smooth a noise floor; two-dimensional over-threshold detection is carried out, namely, an adaptive threshold value and a large signal threshold are calculated, with the larger one in the adaptive threshold value and the large signal threshold adopted as a current detection threshold, over-threshold detection is performed on the transformation result of the STFT; sub-codes aredetected in a two-dimensional over-threshold detection result; data corresponding to each sub-code are intercepted from the original data of the to-be-detected signals according to the detected starting and terminal positions of the sub-codes, Fourier transformation (FFT) is performed, the frequency of the sub-codes can be calculated, and other parameters of the to-be-detected signals are calculated according to the frequency of the sub-codes.

Description

technical field [0001] The invention relates to the technical field of radar signal reconnaissance, in particular to a method for measuring parameters of intrapulse frequency coded signals based on short-time Fourier transform. Background technique [0002] The use of large bandwidth signals is one of the most common methods to improve radar range, speed and their joint resolution performance. Frequency coded signal is a kind of signal with large temporal bandwidth, which has good distance velocity resolution performance and narrow instantaneous bandwidth. Compared with linear frequency modulation signals, frequency coded signals have stronger anti-interference and low interception performance. [0003] Under ideal conditions, accurate parameter measurement results can be obtained through instantaneous frequency measurement, time-frequency analysis, etc. Accurately measuring the parameters of a frequency-encoded signal is difficult. Contents of the invention [0004] In...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S7/285G01S13/28G06K9/00G06T5/00G06T5/10G06T5/30
CPCG01S7/285G01S13/284G06T5/002G06T5/10G06T5/30G06T2207/10044G06T2207/20056G06F2218/04G06F2218/12
Inventor 刘国满高梅国王帅勋李永健
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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