Adaptive-Weighting Schemes for Location-Based Services over Heterogeneous Wireless Networks

Global positioning systems, widely known as GPSs, provide timing, navigation, and positioning signals to military and civilian users. When a GPS receiver receives satellite signals, the distance between the satellite and the user is first calculated, and then the user´s current position is located using the triangulation method. However, there is a possibility that atmospheric conditions, multipath fading, and shadowing effects could have an impact on the satellite signal. As wireless technology has progressed, different user locations and locating systems have been invented, such as the WiFi locating system, which mainly uses received signal strength indication (RSSI) to set up radio maps that provide locations, and RF models to estimate the locations of a moving user. The Zigbee locating system tracks the position of blind nodes, using RF signal strength calculation and known coordinates to estimate the distance between reference points. Using the triangulation method, Zigbee searches for blind node coordinates. This research proposes an adaptive-weighting locating mechanism within wireless heterogeneous networks, which enhances GPS´s ability to receive signals in buildings and precision in estimating locations.