4. Trilateration-Based Target L&T Using RSSI

One of the dominant economical approaches to L&T of the moving target with WSN is the use of RSSI. Trilateration is basically the process of obtaining the position of a target using its distances (computed using a suitable path loss model) from three anchor nodes. Three circles are formed based on these computed distances, and their intersection is used to locate the target node in space. Although the trilateration technique is not sufficient to cope up with the environmental dynamicity efficiently, it is the most basic and widely used technique in the RSSI-based target L&T domain. In this chapter, a trilateration-based L&T approach for tracking of a single mobile target, with the help of deployed WSN, is presented. There are many parameters that impact the performance of RSSI-based L&T algorithm, namely, variations in the velocity of the mobile target, anchor density, and measurement noise in the given RF environment. This chapter covers the experimentation to deal with abrupt variations in the velocity of the mobile target and uncertainties in measurement noises with the help of trilateration. During simulation experimentation the anchor density is varied from 4 to 8 in steps of 2. To understand the effect of abrupt variations in target velocity, we varied velocity abruptly in the range of −2 to 7 m/s at specific time instances. The overall target L&T performance is evaluated in terms of the localization error and RMSE. The simulation result confirms that the trilateration technique is able to track the moving target with the help of WSN, irrespective of environmental dynamicity of the given communication medium.