Dynamic clock synchronization method for underwater acoustic communication based on acoustic link distance measurement and speed measurement

A technology of underwater acoustic communication and clock synchronization, which is applied in multiplex communication, synchronization device, wireless communication, etc., and can solve the problems of synchronization accuracy degradation and other issues

Active Publication Date: 2016-02-10
HARBIN ENG UNIV
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  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to provide a dynamic clock synchronization method for underwater acoustic communication based on acoustic link distance measurement and speed measurement, which solves the problem that the traditional TSHL clock synchronization algorithm and its evolution algorithm decrease the synchronization accuracy when the communication nodes are in relative motion

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  • Dynamic clock synchronization method for underwater acoustic communication based on acoustic link distance measurement and speed measurement
  • Dynamic clock synchronization method for underwater acoustic communication based on acoustic link distance measurement and speed measurement
  • Dynamic clock synchronization method for underwater acoustic communication based on acoustic link distance measurement and speed measurement

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specific Embodiment approach 1

[0056] Specific implementation mode one: combine figure 1 Description of this embodiment, the underwater acoustic communication dynamic clock synchronization method based on acoustic link distance measurement and speed measurement, includes the following steps:

[0057] Step 1. The communication node B transmits the synchronous configuration signal a' according to the pulse interruption with period T generated by the high-precision clock drive, and records the local transmission time T at the same time 1 ; wherein the synchronous configuration signal a' contains a pulse pair composed of two linear frequency modulation signals connected before and after, and the pulse pair is used for the identification of the frame signal and the estimation of the relative motion speed v; the communication node B is the B node;

[0058] Step 2. Communication node A is at T 2 Receive the synchronous configuration signal a' of node B at all times, and solve the relative motion speed v between n...

specific Embodiment approach 2

[0069] Specific implementation mode 2: In step 2 described in this implementation mode, communication node A is at T 2 The specific steps of receiving the synchronous configuration signal a' of node B at all times and obtaining the relative motion speed v between nodes are as follows:

[0070] Step 2.1: Node A performs matched filtering with the locally stored chirp signal d' and the synchronous configuration signal a' received from Node B, and takes the absolute value of the output signal after the matched filtering and passes it through a low-pass filter to obtain the matched The signal envelope e′; the bandwidth of the low-pass filter is equal to the bandwidth of the synchronous configuration signal;

[0071] Step 2.2: Make a threshold judgment on the signal envelope e', and identify the signal envelope e' that exceeds the judgment threshold. If it is satisfied: the length and height of the locally stored chirp signal d' appear on the signal envelope e' or two similar corr...

specific Embodiment approach 3

[0074] Specific implementation mode three: Step 2.3 in this implementation mode obtains the relative motion velocity v between nodes by solving the cross-correlation covariance method,

[0075] The specific steps are as follows:

[0076] By using the cross-correlation covariance method to estimate the frequency offset of the linear frequency modulation signal connected in series, the relative velocity v between the two communication nodes in the synchronization period is estimated according to the Doppler principle, so as to compensate for the movement of the nodes in the synchronization period. The unequal two-way propagation delay improves the accuracy of clock synchronization;

[0077] Node B is at T 1The domain data signal at the moment of transmission is x(k), and its equivalent signal in the multipass frequency band is

[0078] s(k)=x(k)exp(2×pi×j×f tx ×k×T s )(4) where f tx is the transmitted carrier frequency; pi is π, j is the imaginary part; k is the subscript o...

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Abstract

The invention relates to the field of underwater acoustic communication, and specifically relates to a dynamic clock synchronization method for underwater acoustic communication based on acoustic link distance measurement and speed measurement. The dynamic clock synchronization method provided by the invention comprises the steps that: a communication node B interrupts according to pulses with a cycle T and generated by high-precision clock drive; a communication node A receives a synchronization configuration signal a' of the B node at a T2 moment; the B node receives a synchronization request signal b' sent by the A node at a T3 moment at a T4 moment; the A node receives a synchronization response signal c' sent by the B node at a T6 moment; and the B node calculates an obtained clock error (the expression is described in the specification), and the A node calculates the obtained clock error. According to the dynamic clock synchronization method provided by the invention, a relative movement speed between the nodes is estimated by a pulse pair cross covariance algorithm to compensate the condition of unequal two-way propagation delay caused by relative movements of the nodes and improve the clock synchronization precision of the nodes under movement conditions, and when the relative movement speed is 5 sections, the clock synchronization precision can be lower than 1 millisecond.

Description

technical field [0001] The invention relates to the field of underwater acoustic communication, in particular to a dynamic clock synchronization method for underwater acoustic communication based on acoustic link distance measurement and speed measurement. Background technique [0002] In underwater sensor networks, the synchronization performance between nodes is an important factor affecting network performance and ensuring data synchronization transmission. In target detection applications based on sensor networks, on the one hand, the data or results sensed by different sensor nodes in different networks are fused and detected, and the network detection performance is heavily dependent on the synchronization timestamp of node data; on the other hand, the network system Only by relying on a unified time reference can they work together effectively and avoid extra energy loss and network throughput loss caused by unnecessary data transmission collisions. At present, there...

Claims

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Application Information

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IPC IPC(8): H04J3/06H04W56/00
Inventor 张友文孙大军李想刘璐范巍巍刘衍超王鹏勇俊刘鑫
Owner HARBIN ENG UNIV
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