Method for tracking and positioning mobile node of wireless sensor network

Abstract

The invention relates to a method for tracking and positioning a mobile node of a wireless sensor network, which comprises the following steps: in a measurement positioning period, sending low repeated frequency pulse beacon signals for at least four times at known time intervals by the mobile node approximately keeping uniform speed rectilinear motion, receiving the beacon signals continuously for four times by a main anchoring node, measuring self time difference to acquire three self time difference relation expressions relative to an initial measurement moment, providing two trigonometric function equations from a positioning measurement triangle consisting of a motion locus of the mobile node and a motion radius vector of detection wave by using the cosine theorem, and simultaneously solving the equations so as to determine the relative distance and speed between the mobile node and the anchoring nodes; and further, by adopting the technology of beacon retransmission, retransmitting the beacon signals sent by the mobile node for the last time to the main anchoring node by two auxiliary anchoring nodes so as to achieve asynchronous coordinate positioning of the mobile node. The method can achieve tracking and positioning of a mobile target without time synchronization among the anchoring nodes.

Description

Technical field: [0001] The invention belongs to the field of radio tracking and positioning, and specifically relates to a wireless sensor network (WSN), which does not require time synchronization between anchor nodes, and the anchor node uses the pulse calibration signal sent by the mobile node to perform self-time difference measurement, and applies The beacon forwarding method realizes the tracking and positioning method for the mobile node. Background technique: [0002] The node location of wireless sensor network plays an important role in the whole sensor network system. First of all, location information is needed to determine the source of information; secondly, some system functions of sensor networks need location information; finally, location information is also beneficial to service applications in sensor networks. [0003] In practical applications, many monitored targets are moving in real time, and wireless sensors are often placed on these targets. In o...

AI Technical Summary

Problems solved by technology

At present, most of the research on wireless sensor networks at home and abroad is limited to the case where all sensor nodes are stationary. The existing ranging-based positioning technology includes received signal strength (received signal strength indicator, RSSI), time of arrival (time of arrival) , TOA), time difference on arrival (TDOA) and angle of arrival (AOA), etc., there are more or less limitations: RSSI meets the requirements of low power and low cost, but it is possible Generates a ranging error of ±50%; TOA requires precise time synchronization between nodes; TDOA technology is limited by the short ultrasonic propagation distance and the requirements for line-of-sight propagation; AOA is also affected by the external environment and requires additional hardware support to implementation, may not be available for sensor nodes in terms of hardware size and power consumption

[0005] Among the existing positioning algorithms that can be used for mobile nodes under study, network positioning methods based on network connections can only be applied to static or slow moving situations, while adaptive methods and prediction methods for high-speed mobile nodes still exist. There are problems such as large amount of calculation and limited accuracy improvement

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