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A wavelet denoising preprocessing method for emergency location in vdes

A wavelet denoising and preprocessing technology, applied in satellite radio beacon positioning systems, radio wave measurement systems, instruments, etc., to achieve the effect of improving relative positioning accuracy

Active Publication Date: 2021-02-23
北京大瞭互通科技有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The present invention provides a wavelet denoising preprocessing method for emergency positioning in VDES to overcome the shortcomings of existing wavelet denoising preprocessing methods

Method used

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  • A wavelet denoising preprocessing method for emergency location in vdes
  • A wavelet denoising preprocessing method for emergency location in vdes
  • A wavelet denoising preprocessing method for emergency location in vdes

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Embodiment 1

[0040] figure 1 It is a schematic diagram of a wavelet denoising preprocessing method for emergency positioning in VDES according to an embodiment of the present invention, refer to figure 1 , the method, including:

[0041] S1 acquires TOA measurements between ships in VDES.

[0042] S2 performs wavelet decomposition on the TOA measurement value, and selects an initial decomposition level.

[0043] S3 Calculate the energy coefficient of each level according to the initial decomposition level, and determine the decomposition level according to the energy coefficient.

[0044] S4 Calculate the positive and negative thresholds of each level according to the determined decomposition levels.

[0045] S5 uses a modified threshold function to perform threshold processing on the wavelet coefficients according to the positive and negative thresholds of each level.

[0046] S6 uses the thresholded wavelet coefficients to perform inverse transformation to obtain an estimated TOA value...

Embodiment 2

[0086] In this embodiment, it is assumed that the initial number of surrounding ships is 3, and the relative positions of the ships to be positioned and the surrounding ships, figure 2 The relative position schematic diagram of the ship of present embodiment, as figure 2 As shown in , two of the surrounding ships are 27 nautical miles away from the ship to be positioned, which is the normal travel distance between ships at sea; the other surrounding ship is 5 nautical miles away from the ship to be positioned, which is the distance at which avoidance actions should be taken in the rules for avoiding collisions at sea . The service ship broadcasts information to the surrounding ships in the emergency positioning environment, and obtains the TOA measurement value, wherein the TOA measurement value contains the measurement error, and the measurement error obeys the mean value of 0, and the variance is 30m, 60m, 90m, 120m, 150m, 180m, 210m Gaussian normal distribution. Perform...

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Abstract

The invention provides a wavelet denoising preprocessing method for emergency positioning in VDES, comprising: obtaining TOA measurement values ​​between ships in VDES; performing wavelet decomposition on TOA measurement values, and selecting an initial decomposition level; Decompose the level, calculate the energy coefficient of each level, and determine the decomposition level according to the energy coefficient; calculate the positive and negative thresholds of each level according to the determined decomposition level; use the modified threshold function according to the positive and negative thresholds of each level Perform threshold processing on the wavelet coefficients; perform inverse transformation on the thresholded wavelet coefficients to obtain TOA estimated values, and use TOA estimated values ​​for subsequent positioning. The invention denoises the TOA measurement noise of the ship-ship VDE communication channel, and improves the relative positioning accuracy of the ship.

Description

technical field [0001] The invention relates to the technical field of ship communication, in particular to a wavelet denoising preprocessing method for emergency positioning in VDES. Background technique [0002] The current maritime positioning method mainly relies on satellite automatic identification system (Automatic Identification System, AIS) for positioning, but when the satellite positioning equipment fails or the signal is poor, an emergency positioning solution is needed to avoid collisions between ships. [0003] The wireless propagation channel of the ship-ship VHF Data Exchange (VDE) has the characteristics of time-varying and multipath effects, which lead to serious noise interference on the measurement time. If the time of arrival (Time of Arrival, TOA) measurement value is directly used for positioning, it is difficult to improve the positioning accuracy. [0004] In 2015, Gong Pengan et al. proposed a Time Difference of Arrival (TDOA) positioning algorithm...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04W64/00G01S19/14
Inventor 侯舒娟李海张钦孙昕宋政育朱文萍
Owner 北京大瞭互通科技有限责任公司