ABSTRACT
Locations of devices or objects are important information in many applications. In addition to the global positioning system (GPS) system, positioning can also be done using some wireless networking infrastructures. Several location estimation models, such as angle of arrival (AoA); time of arrival (ToA); received signal strength (RSS); phase of arrival (PoA); and assisted GPS (A-GPS), are widely used in cellular networks and wireless sensor networks. Much work has been dedicated to positioning and location tracking in the area of wireless ad hoc and sensor networks. This chapter introduces some fundamental distance estimation models, discusses some positioning and location tracking algorithms and reviews some experimental systems. To position an object or a device, the basic step is to use a reference point to determine the distance and angle between the device and the reference point. The chapter shows how to use multiple reference points jointly to estimate the location of a device.
