Stereo Analysis for Vision-Based Guidance and Control of Aircraft Landing

Abstract

This work considers the feasibility of binocular stereo imaging for use in aircraft guidance and control. Of particular interest is the use of stereo-based ranging as an aid in autonomous or semiautonomous landing of General Aviation (GA) class aircraft. With monocular image analysis, an aircraft’s position can be estimated up to a scale factor only, unless prior knowledge (e.g., width of the runway) is available. With calibrated stereo cameras, complete three-dimensional position and orientation estimates are possible when point correspondences are known for the two images. The major difficulty, however, lies in the development of algorithms that can identify the runway and determine point correspondences reliably. This paper presents a method for detecting runway edges and estimating distances from the aircraft to the touchdown point during an approach. The method has been tested using stereo image sequences obtained during flight tests in the Hampton Roads, Virginia area. These tests have allowed us to examine the effectiveness of stereo matching techniques for images of precision and nonprecision runways during landing operations. Additional tests involving feature tracking and optic flow recovery were conducted at a visual runway. Although full calibration was not available for accuracy assessment, regression analysis indicated very good results (