Wireless sensor network node location technology analysis: As a new information acquisition and processing technology, wireless sensor network has broad application prospects in target tracking, intrusion detection and some related fields. However, the positioning technology is the basic technology of the wireless sensor network, which plays a key supporting role in the development and application of the wireless sensor network. The new wireless sensor network positioning method mainly includes the positioning algorithm based on the mobile anchor node, the three-dimensional positioning algorithm and the intelligent positioning algorithm. From the aspects of practicality, application environment, hardware conditions, power supply and security privacy.
Mobile network based positioning technology and mobile terminal based positioning technology. Indoor positioning technology has higher requirements for technology due to the complexity of the indoor environment. What is node positioning? Node positioning plays an important role in the entire sensor network, and is an indispensable link in event observation, target tracking, and network reconstruction.
The easiest way to locate a wireless sensor network is to load a Global Positioning System (GPS) receiver for each node to determine the node location. However, due to economic factors, node energy constraints, and GPS constraints on the deployment environment, the feasibility of the solution is poor. Therefore, typically only a small number of nodes acquire their own coordinates by loading GPS or by pre-deploying them at specific locations. In addition, the node location of wireless sensor networks involves many aspects, including positioning accuracy, network size, anchor node density, network fault tolerance and robustness, and power consumption. How to balance the relationship between various relationships for wireless sensor networks Very challenging.
The method of pre-testing the environmental parameters is small in the actual positioning. Such methods only need to be simple to look up the table or calculate according to the fitting curve. The disadvantage is that a lot of preparation work needs to be done before the experiment, and once the environment changes, the The established model will no longer apply. The method of not needing to test the environmental parameters in advance requires the calculation operation of the positioning engine, and often has a complicated calculation process, but the adaptability is strong.
The node location in the wireless sensor network refers to the process in which the sensor node determines the location information of other nodes in the network through certain positioning techniques according to the location information of a few known nodes in the network.
In a wireless sensor network, a node can be generally divided into a beacon node or an anchor node, and a beacon node is also called an anchor node or a reference point, and an unknown node is also called a common node. A beacon node is a node whose location information is known, and an unknown node is a node whose unknown information is unknown. Beacon nodes generally have a small proportion, and are usually obtained by manual configuration or equipped with a GPS receiver to obtain their own location information.
1) Received Signal Strength Indication (RSSI): The propagation loss is calculated by measuring the transmit power and the received power. Using theoretical and empirical models, the propagation loss is translated into the distance between the transmitter and the receiver.
2) Arrival time (ToA): By measuring the transmission time to break the distance between the two borrowing points, the accuracy is better, but due to the fast transmission speed of the wireless signal, a small error in the time measurement will lead to a large error. The value requires that the sensor node has a strong computing power.
3) Time difference of arrival (TDoA): In the TdoA-based positioning mechanism, the transmitting node simultaneously transmits two wireless signals with different propagation speeds, and the receiving point calculates the two nodes according to the time difference between the arrival of the two signals and the propagation speed of the two signals. The distance between them.
4) Angle of Arrival (AoA): The angle of arrival of the wireless signal transmitted by other nodes is estimated by a special antenna, and the hardware requirement is high.