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Method for Doppler estimation and synchronization of mobile water sound communication signal

A Doppler estimation and underwater acoustic communication technology, which is applied in the field of synchronization and Doppler offset estimation in mobile underwater acoustic communication, can solve problems such as inability to work, and achieve the effect of accurate Doppler and synchronization estimation

Active Publication Date: 2009-12-02
JIANGSU ZHONGKUANG HEAVY EQUIP CO LTD +1
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Problems solved by technology

This method takes up less memory, but like the first three methods, it cannot work when the UUV is moving at high speed

Method used

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  • Method for Doppler estimation and synchronization of mobile water sound communication signal
  • Method for Doppler estimation and synchronization of mobile water sound communication signal
  • Method for Doppler estimation and synchronization of mobile water sound communication signal

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Embodiment Construction

[0026] In the present invention, the frame synchronization signal adopts two identical linear frequency modulation (LFM) signals s(t), which can be expressed as:

[0027] s(t)=sin(2πf l t+πμt 2 ) t∈[0, T] (1)

[0028] where f i is the starting frequency of the LFM signal, μ is the modulation rate of the linear frequency modulation signal, μ>0 is positive frequency modulation, μ<0 is negative frequency modulation, T is the signal pulse width, and the signal bandwidth is B. The following relations are established

[0029] B=μT (2)

[0030] There is an identification signal I(t) between the two chirp signals. Its purpose is to have two points: (1). Identify the modulation method or parameters; (2). Improve the accuracy of Doppler estimation. Combine the three-segment signals to form a frame synchronization signal, which can be expressed as

[0031] p(t)=[s(t) I(t) s(t)] (3)

[0032] Wherein, it is assumed that the duration of the first two sections of signals is D.

[0033...

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Abstract

The invention discloses a method for the Doppler estimation and synchronization of a mobile water sound communication signal, which comprises the following steps: selecting two chirp signals and using a time interval between the two chirp signals as a frame synchronizing signal; sampling a receipt signal, performing cross-correlation treatment of a receipt sampling signal and a delay signal thereof, calculating an absolute value of a correlation function, comparing the absolute value with a threshold and continuing to perform sliding-correlation treatment if the absolute value is smaller than the threshold; if the absolute value is greater than the threshold, determining the arrival of a synchronizing signal, doubling the length of an observation window of the cross-correlation treatment, calculating a correlation function of the receipt sampling signal and the delay signal thereof, calculating the absolute value of the correlation function, determining the time corresponding to a maximum absolute value and the offset of the central point of the correlation function and calculating a Doppler factor; resampling a duplicate signal to obtain a duplicate signal under Doppler influences, performing the correlation treatment of the duplicate signal and the receipt signal; and calculating the time corresponding to the maximum value of a correlation function and using the time as the initial time of the frame synchronizing signal. The method can work in a large Doppler environment to provide accurate Doppler estimation and synchronization.

Description

technical field [0001] The invention belongs to the field of underwater acoustic communication, and relates to a method for synchronizing and Doppler offset estimation in mobile underwater acoustic communication. Background technique [0002] As an important tool for ocean exploration, underwater unmanned vehicle (UUV) has become a research hotspot in the field of ocean engineering in various countries. Among them, mobile underwater acoustic communication applied to UUV high-speed movement is a world-wide technology covering ocean technology and information technology. One of the high-tech urgently needed by all countries. [0003] Underwater acoustic channels can generally be characterized as time-, frequency-, and space-variant channels with limited bandwidth and severe multipath interference. The complexity and variability of underwater acoustic channels severely limit the performance of underwater acoustic communication. In particular, for mobile underwater acoustic co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B13/02
Inventor 何成兵黄建国张群飞雷开卓申晓红韩晶
Owner JIANGSU ZHONGKUANG HEAVY EQUIP CO LTD
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