Position and Orientation for Distributed Sensors (PODIS)

The success of remote sensing using a network of distributed sensors depends on knowing the position and orientation of each sensor. However, in many sensor deployments, accurate knowledge of sensor locations and orientations is unavailable. We propose todevelop and demonstrate an innovative and robust technique for self-locating and self-orienting of the sensors that meets the cost, size, and weight requirements of sensor nodes. The techniques will use acoustic and/or RF signals to determine relativerange and bearing of signals, and this information is fused to compute the locations and orientations of all sensors. Significantly, the source signals may be at unknown locations, and need not be co-located with sensors. Both relative sensor calibration(with respect to one another) and absolute calibration techniques (with respect to an absolute frame of reference) will be developed. In addition, accuracy bounds for calibration performance will be found. We will develop a clear understanding of theadvantages and limitations of both RF-based and acoustic-based self-calibration methods. We will also develop an innovative algorithm suite for robust self-calibration and demonstrate, via software simulation, the ability to robustly self-calibratesensors separated by 30-500 meters using these techniques. Finally, we will identify critical algorithmic and system implementation issues that need to be addressed to improve robustness of the self-calibration system in a Phase II design. Theself-calibration techniques will be developed for Phase II implementation as part of a sensor network system. A robust, self-contained system for localization and orientation is critical for providing accurate tracking and targeting information to thewarfighter in areas where other sensing assets are blind or denied. Commercial applications in sensor networks have application for locating people in burning buildings or forests, providing distributed sensing of large public areas for homeland security,and developing smart houses.