Doppler assisted underwater sensor network time sync method

Abstract

The invention discloses a Doppler assisted underwater sensor network time sync method. A beacon node continuously broadcasts message data packets; a to-be-synced node continuously receives the messages broadcasted by the beacon node; the native time of the to-be-synced node is recorded each time when the messages are received; the relative speed between the to-be-synced node and the beacon node is calculated; the to-be-synced node calculates clock frequency deviation by employing collected data; after the to-be-synced node calculates the clock frequency deviation, a request message is sent to the beacon node; after the beacon node receives the request message sent by the to-be-synced node, a response message is sent to the to-be-synced node after a random period of time; when the to-be-synced node receives the response message sent by the beacon node, the native time is recorded; the relative speed between the to-be-synced node and the beacon node is calculated by employing a calculation method; and finally the final clock phase deviation is calculated through the collected data. According to the method, the negative effects of node movement on time sync can be reduced, and therefore, the time sync precision is improved.

Description

technical field [0001] The invention belongs to the field of underwater wireless sensor networks, in particular to a Doppler-assisted underwater sensor network time synchronization method. Background technique [0002] The application prospect of underwater wireless sensor network is very broad, not only in industry and agriculture, but also in environmental monitoring of chemical or biological indicators, disaster prevention and underwater survey. Time synchronization is one of the key issues in sensor networks. Different sensor nodes need to work together, which is very important for most of the tasks that wireless sensor networks will perform. These tasks include target tracking, surveillance, bio-survey, distributed beamforming Wait. [0003] In view of the mobility of underwater nodes, Chirdchoo N et al. proposed the MU-Sync synchronization method, which divides the entire network into multiple clusters. The interaction of secondary information calculates the frequenc...

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Problems solved by technology

However, when the nodes move faster, the round-trip propagation delay is different, which affects the synchronization accuracy; and in practical applications, the algorithm requires more beacon nodes to be deployed evenly, which increases the deployment cost of the sensor network, and the deployment scheme is easily affected by the underwater environment. impact, lack of flexibility and adaptability

[0004] Aiming at the characteristics that node movement is affected by ocean currents, Li Z et al. proposed E 2 The DTS algorithm uses a mobile autonomous underwater vehicle (AUV) as a beacon node, and the communication between the AUV and the sensor node adopts a single sending method and a sending-receiving method, which saves energy in this way consumption, but the algorithm assumes that the node is affected by the ocean current to move at a constant speed during the synchronization process, which limits the synchronization accuracy of the method

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