Effects of Stereo Vision Camera Positioning on Relative Navigation Accuracy

When two aircraft are cooperatively performing a mission, the accuracy of relative navigation estimates are critical for the the safety, accuracy and success of their operations. This paper considers a cooperative aerial refueling scenario where stereo cameras are used on the tanker to direct a "boom" (a large, long structure through which the fuel will flow) into a port on the receiver aircraft. In particular, we seek the optimal system design for the camera system to achieve the most accurate relative navigation estimates. The testing process consists of utilizing a simulation engine and recreating real world flights based on previously collected Global Positioning System (GPS) data. Using the pose estimation results and the ground truth information, the system computes the error between the incoming aircraft's position in the virtual world and its calculated location based on our stereo matching algorithm. We include both un-obscured scenarios and cases where the boom causes significant occlusions in the camera images. We describe the connection between accuracy and the horizontal separation between cameras in this (relatively speaking) longer-distance relative navigation problem. We also find the best placement of the cameras with respect to the boom to overcome the negative effects of occlusions. The results define the improvements in position and orientation estimation of camera positioning from the consolidated simulation data. Conclusions drawn from this data provide recommendations for future relative navigation research.