Theory of Optical IMU Aiding; Loose, Tight, Ultra-Tight Optical Flow Coupling to Inertial Navigation Systems

Modern UAV systems depend critically on GPS/INS systems to provide precise navigation data for controlling flight. When GPS is denied, INS measurements drift to a point where they are no longer useful for navigation and flight control. During Phase I, the SET/AFIT team has demonstrated a successful design and implementation for high accuracy navigation from optical IMU coupling to correct IMU drift. Multiple orders of magnitude enhancement in navigation accuracy was demonstrated for both consumer and navigation grade IMU sensors. The design focuses on the underlying mathematical modeling to tightly couple video measurements to INS navigation parameters, automatically extract feature depth corrections within this tight coupling, and automate the addition and dropping of features necessary to perform video/IMU navigation without reliance on external correction sources. Phase II efforts will focus on the development of a fully integrated system for airborne operation based on our design for tightly coupled video/IMU navigation estimation with extensive performance evaluation. The design has the benefit of autonomy from external aiding sources with the capability of high-accuracy independent navigation. We will extend operation of the Phase I system to produce a fully developed, evaluated prototype that we will deliver and demonstrate to the Air Force.