Method of initial alignment of the video-inertial navigation system for an unmanned aerial vehicle

An analysis of existing methods of initial alignment revealed that the alignment process of modern strapdown inertial navigation systems can take more than five minutes. The issue of alignment is especially acute for strapdown inertial navigation systems based on microelectromechanical systems (MEMS), which are traditionally installed on short-range unmanned aerial vehicles (UAVs). The low accuracy characteristics of modern MEMS do not allow for autonomous initial alignment of strapdown inertial navigation systems using the gyrocompassing method. Aim of work – development of a method for the initial alignment of an unmanned aerial vehicle's video-inertial navigation system that ensures high accuracy, automatic execution, and minimal initialization time without the use of additional equipment in conditions of absent or limited availability of satellite navigation system signals. A new method for the initial alignment and compensation of gyroscope block errors in a video-inertial navigation system has been developed. This method differs from previously known methods (such as gyrocompassing, the use of stored coordinates, or satellite signals) by utilizing an onboard monocular vision system and a constellation of three ground-based beacons. It is based on the method of generalized angulation – a mathematical approach that determines the position of an object in space by using angles between directions to several known points. This ensures the determination of the UAV’s initial angular and linear position, as well as the drift vector of the gyroscope block. An experimental setup was developed, and tests confirmed the high efficiency of the proposed method: measurement errors were 0.001 meters for linear coordinates and 0.01 degrees for angular coordinates within 10 seconds, which is 16 times better than alignment using existing methods. The developed method can be used by industrial organizations and research institutions in the design of UAV navigation systems based on optoelectronic components to expand their tactical capabilities.