Simultaneous localization and mobile robot navigation in a hybrid sensor network

This paper discusses a range free localization algorithm for the wireless sensors in a hybrid sensor network, which consists of a large number of static sensors and relatively small number of mobile robots. The mobile robots are equipped with either global positioning systems (GPS) or other localization devices. By moving the mobile robots and broadcasting their locations in the sensor network, the static sensors are able to estimate their position based on the messages received. A mobile robot navigation in a un-localized sensor network is further developed. As and when an event occurs in the sensor network, a mobile robot can be navigated by the un-localized sensor nodes to the event location, which in turn are finely localized by the mobile robot. The mobile robot, equipped with advanced sensing and communication capabilities, can enhance the sensing in the area of event location. This algorithm works well in an event driven network wherein both the localization of the sensor nodes and navigation of the mobile robot to the event is done simultaneously. As the frequency of the event increases the nodes are better localized and the precision of the node´s location becomes finer. Simulation results have been used to verify the effectiveness of the proposed algorithms.