Vision-Based Target Geolocation UsingMicro Air Vehicles

Abstract

A method for determining the location of a stationary ground target when imaged from the air using a camera-equipped micro air vehicle is developed. The ground object's elevation is assumed known. Rather than a one-shot affair, multiple bearing measurements of the ground object taken as the aircraft flies around the target are used. This makes it possible for the adverse effects of both the random measurement errors and the systematic measurement errors (i.e., attitude sensors' biases) to be mitigated. The main result of this paper is that when bearing measurements of a target are taken over time, the target's position and the micro air vehicle's systematic attitude-measurement errors can be jointly estimated using linear regression. As a result,the target is accurately geolocated and the attitude sensors are calibrated. If only one snap bearing measurement of the target can be taken, the attitude sensors will be calibrated before arrival at the target area using an initial point The technique was successfully tested on actual flight data collected during multiple micro air vehicle operations for cooperative geolocation of unknown targets.