Accurate 3-D Positioning of Aircraft Based on Laser Rangefinder Combining Monocular Vision Measurement

Pose parameters constitute the fundamental flight state parameters of aircraft, providing a pivotal basis for aircraft design, performance evaluation, and flight safety assurance. The positional accuracy of vision measurements is often limited by the measurement distance. In response to the challenges associated with measuring the landing position of aircraft, the laser ranging (LR) position compensation method (PCM) is proposed by combining a laser rangefinder (LRF) with the vision system to realize high-precision dynamic positioning of fixed-wing aircraft. Our method involves the construction of a laser-vision system to track and capture the aircraft images and the object distances. The aircraft attitude parameters are measured by combining a 6-D initial pose estimation and the pose tracking method. In addition, leveraging the estimated 6-D pose parameters and aircraft 3-D model, the dense 3-D coordinates map of the aircraft is rendered to locate the laser reflection point (LRP) on the aircraft’s surface and infer the origin of the aircraft coordinate frame accurately. By establishing the flight simulation scene, the position error effects caused by 6-D pose errors, LR assembling errors, and LR errors are simulated and analyzed numerically. The theoretical error propagation models are derived to corroborate the numerical simulation results. In a real flight test within a 3-km landing range, the rms errors of the aircraft attitude are below 0.5°, the SDs of the aircraft position errors are less than 1.5 m, and the measurement rate exceeds 60 frames/s, which demonstrates that the proposed method can be used for accurate real-time measurements of aircraft attitude and position.