| Summary: | 碩士 === 國立交通大學 === 電控工程研究所 === 100 === Wireless sensor network (WSN) localization is demanded in many modern applications, like landslide detection, precision agriculture, health care, etc.
By leveraging the anchor nodes, sensor nodes in a WSN can be localized.
The more precise the position of an anchor node is, the more accurate the localization of a sensor node can be.
To provide the accurate positions of an anchor node, many studies have taken advantage of a GPS device placed in the outdoor environment.
Since the GPS device cannot work properly in an indoor environment, some existing localization methods also adopt the configuration of the anchor node in a manual fashion.
However, manually configuring anchor nodes is not suitable for large-scale WSNs and artificial errors may be propagated and thus affect the result of the WSN localization.
In this paper, we study several reverse localization methods regarding locating wireless access points (AP) in an 802.11 wireless network. Some of these methods still rely on the GPS modules for AP positioning, and some others strictly restrict the training conditions.
As an improvement, we propose a novel approach to locate anchor nodes in a WSN without any GPS modules or strict traninig restrictions.
Considering the individual differences of wireless chips, we apply the calibration before reversely locating the anchor nodes to obtain the RSSI (received signal strength indicator) coefficients for estimating the distance between two nodes.
We conduct a series of experiments with MSP430FS5438/CC2500EMK devices to study the tradeoff between the accuracy and running cost.
We also demonstrate how the proposed approach estimates the anchor nodes and applies the estimation to an existing localization method.
The result shows that 1) better accuracy can be obtained if we apply the calibration or remove the training restrictions; 2) there is a gap of 9.25\% errors in average between the real and estimated anchor positions.
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