Multitarget Three-Dimensional Indoor Navigation on a PDA in a Wireless Sensor Network

The development of wireless sensor networks has greatly encouraged the use of sensors in the location tracking industry by introducing various researches have exploited the high accuracy of position determination using distinct tracking models predominantly as low-cost solutions. This paper presents an indoor tracking model that uses the depreciated IEEE 802.15.4 compliant radio frequency and immersive 3-D graphics to present data in an extraordinary way. Our motivation is to manipulate the erratic and unstable received signal strength indicator (RSSI) signal to deliver stable and precise position information in an indoor environment. A sensor (target node) receives RSSI signals from at least three designated sensors (reference nodes) and predicts the location on the basis of trilateration. The nature of a limited indoor space is such that there is signal fluctuation and noise in radio-frequency transmission between sensors. In light of this issue, we proposed an accuracy refinement algorithm to filter out noise in the received RSSI signals. To display useful 3-D information, an additional feature is required in conjunction with the user´s position to illustrate the view of the user. Therefore, a digital magnetic compass is used to determine the orientation of the target in real- time and a sensor transmits DMC data to a receiver in wireless transmission.