3D virtual viewer on mobile device for wireless sensor network-based RSSI indoor tracking system

Most of recent research on indoor location sensing information has been presented in dull and unpleasant 2D image standard. This paper focuses on high precision three-dimensional received signal strength indication (RSSI)-based location information in an interactive virtual reality on PDA. The developed system operates by capturing and extracting signal strength information at multiple pre-defined reference nodes to provide information in the area of interest, thus updating user's location in 3D indoor virtual map. Virtual Reality Modeling Language (VRML), which specifically developed for 3D objects modeling is utilized to design 3D indoor environment. To shorten the rendering time in low-power processing PDA, culling algorithm is introduced to render only essential 3D objects needed for navigation. Meanwhile, RSSI accuracy refinement algorithm introduced reduces noises in signal strength mainly caused by the effect of reflecting and attenuating objects in the indoor environment. PDA user's position is computed with respect to VRML specification, synchronized with real indoor environment. Moreover, interpolating of digital magnetic compass shows real-time dynamic orientation processing, generated projected 3D view to be displayed on PDA screen.