Cart-mounted geolocation system for unexploded ordnance with adaptive ZUPT assistance

Reliable and precise navigation technology is essential for robust detection and discrimination of unexploded ordnance (UXO) in a wide range of field conditions, including GPS-challenged environment. Based on the fact that the UXO detection involves frequent stops, this paper proposes an adaptive ZUPT (AZUPT) algorithm in a sliding time window to guarantee the correct identification of the zero velocity condition and improve the position accuracy of UXO geolocation. Furthermore, a known zero velocity-based prefiltering method is used to remove INS sensor errors. A pushcart-based prototype in which the tactical-grade inertial measurement unit and geodetic-grade GPS receiver are mounted is designed for the geolocation system. Field test was undertaken, and simulated GPS outages were introduced to the data. The result shows that AZUPT precisely identified the zero velocity and greatly improved the positioning accuracy of the cart-mounted UXO geolocation system.