Rocket bomb muzzle velocity measurement method based on improved short-time Fourier transform

A speed measurement and instantaneous speed technology, applied in the direction of measuring device, radio wave measurement system, sound wave reradiation, etc., can solve the difficulty of echo signal extraction, low measurement accuracy, large amount of calculation for rocket muzzle initial velocity measurement, etc. problem, to achieve the effect of high spectrum accuracy, high measurement accuracy, and small amount of calculation

Active Publication Date: 2017-06-20
NANJING UNIV OF SCI & TECH
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Problems solved by technology

[0006] In short, the problems existing in the existing technology are: it is difficult to extract the radar echo signal of the rocket with a low signal-to-noise ratio, and the measurement and calculation of the initial velocity of the rocket muzzle is large, and the measurement accuracy is low

Method used

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  • Rocket bomb muzzle velocity measurement method based on improved short-time Fourier transform
  • Rocket bomb muzzle velocity measurement method based on improved short-time Fourier transform
  • Rocket bomb muzzle velocity measurement method based on improved short-time Fourier transform

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Embodiment 1

[0053] The firing process of the rocket is divided into two stages, namely inside the gun bore and outside the gun bore. The present invention relates to external ballistic speed measurement. The radar emits 35GHz continuous waves along the rocket flying direction and at a small angle, and the zero point of the rocket launch time is consistent with the radar. When the rocket flies into the range of the radar beam, the received echo signal contains the information of the rocket, and the muzzle velocity of the rocket is obtained through the processing method of the present invention. According to the method of the present invention, table 1 is the final fitting data of the time and speed of the V-T curve fitted by the useful signal of the single-shot rocket in Example 1.

[0054] Table 1 Velocity fitting data of a single rocket

[0055]

[0056] It can be seen from the table that the speed of the rocket after ejecting from the muzzle is similar to uniform acceleration in a s...

example 1

[0059] In Example 1, the window length and FFT of 1024 points are used to realize the processing of single-shot rockets. In this example, the window length and the number of sliding window groups in Example 1 are increased to measure the velocity of rockets launched continuously. Since the rocket is launched every 1 second, increasing the number of groups of the sliding window is equivalent to increasing the amount of processed data and increasing the time length, thereby detecting the data of the next rocket. For the convenience of simulation, this example adopts 2048 points of FFT to obtain the power spectrum, and illustrates the method of the present invention with the first three rounds of rockets fired continuously. Since each rocket is launched at an interval of 1s, the time for the first rocket to pop out of the muzzle is 0.13s, the time for the second rocket to pop out of the muzzle is 1.13s, and the time for the third rocket to pop out of the muzzle is 2.13s. Figures...

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Abstract

The invention discloses a rocket bomb muzzle velocity measurement method based on improved short-time Fourier transform, comprising the following steps: (10) echo signal windowing: discretizing echo data of a rocket bomb measured by radar, and using a Blackman window to carry out time-domain windowing on the discretized data; (20) power spectrum waterfall plot acquiring: constantly sliding time-domain windows, carrying out time-domain signal reconstruction, low-frequency coefficient extraction and instantaneous velocity calculation on the echo data in each time-domain window, and drawing a power spectrum waterfall plot according to the power spectrums in all the time-domain windows; and (30) muzzle velocity determining: finding out the position of the signal according to the power spectrum waterfall plot, fitting out the muzzle velocity of the rocket bomb according to the Doppler frequency-velocity relationship corresponding to the peak, and drawing a velocity fitted curve of the rocket bomb. The invention aims to provide a rocket bomb muzzle velocity measurement method based on short-time Fourier transform, which has the advantages of small amount of calculation and high measurement accuracy.

Description

technical field [0001] The invention belongs to the technical field of radar velocity measurement, in particular to a rocket muzzle velocity measurement method based on improved short-time Fourier transform with small calculation amount and high precision. Background technique [0002] The measurement of the initial velocity of the rocket, that is, the muzzle velocity, is of great significance to the development of weapon systems and the development of ballistic theory. [0003] The echo signals of rockets belong to the category of non-stationary signals, and the analysis methods of non-stationary signals mainly include the following types: short-time Fourier transform, wavelet transform, WVD (Wigner-Ville Distribution) transform, fractional Fourier transform, polynomial phase Transformation, Dechirp transformation method and so on. [0004] The short-time Fourier transform divides a changing signal into several time periods, calculates the signal spectrum in each time peri...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S15/58G06F17/14
CPCG01S15/586G06F17/141
Inventor 蔡征宇张建城程风雷严丽萍张天乐吕云涛陈颖袁小琦杜禹周文忠
Owner NANJING UNIV OF SCI & TECH
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