Scenario-based evaluations of high-accuracy personal positioning systems

Foot-mounted inertial sensors combined with GPS-receivers, magnetometers, and barometric pressure sensors have shown great potential in providing high-accuracy positioning systems for first responder and military applications. Several factors, including the type of movement, surface, and the shape of the trajectory, can strongly influence the performance of foot-mounted inertial navigation systems. There is a need for realistic scenario-based evaluations as a complement to the controlled environment tests that have been published in the literature. In this work we evaluate the performance of a foot-mounted inertial navigation system using three-axis accelerometers, gyroscopes and magnetometers during realistic scenario-based measurements. The position accuracy is evaluated by using a camera-based reference system which positions itself towards visual markers placed at pre-surveyed positions, using a slightly modified version of the ARToolKitPlus software. Maximum position errors of 2.5 to 5.5 meters were obtained during four separate high-tempo building clearing operations that lasted approximately three and a half minutes each. Further improvements in accuracy, as well as improved robustness towards different movement patterns, can be achieved by implementing an adaptive stand-still detection algorithm.