A Survey on Vision Navigation Methods for UAV Navigation Applications

Inertial navigation system error increases due to sensor errors with the increase in time. Usually, to prevent the growth of navigation system error, inertial navigation systems are integrated with sensors or auxiliary systems. The importantly aided system is GNSS. Because of GNSS outage or its invalidity, the other auxiliary sensors are used to increase the accuracy of the inertial navigation system. In this article, the types of methods which are used by imaging camera for navigation or for the accuracy improvement of an inertial navigation system for UAVs are discussed. After reviewing the literature in the field of vision navigation in UAVs, the proper classification for vision navigation methods and the development of these methods are presented. In UAVs, the vision navigation techniques are based more on Map metric, optical flow, feature tracking, odometers and simultaneous localization and mapping.