Edge-based Cooperative Localization in Wireless Sensor Networks

Abstract

Localization is important in Wireless Sensor Networks (WSN) applications. When a sensor is deployed, its sensor data is often of limited use unless the position of the sensor is known when the measurement was taken. This research is conducted to solve the grid spacing of more than 30 meters because this grid spacing setup would lead to some nodes having insufficient beacon messages (i.e. 4 or more) to localize their positions. If only a portion of nodes is localized, then a so-called cooperative localization can be used. These experiments use a probabilistic simulation environment which allows large numbers of experiments to be run to reduce the random effects from the imprecise nature of Received Signal Strength Indicator (RSSI) ranging. These experiments are undertaken where a flight path attempts to localize blind nodes just around the edges of the sensing areas by using a mobile anchor, and then to use cooperative localization to progressively localize all the other nodes. The parameters used are number of reference node, their uncertainty for virtual anchors, quality of range estimates and 3D - geometry. The flight path consists of three loops at alternate 10m, 13m, and 10m heights, with these loops spaced 50 m apart, and the total length is 4.8 km Edge-based path planning can use localize a ring around the edge of the sensing area, but in order for this localization to propagate into a central area with no mobile beacon messages, an impractically high node density is required