Tightly-Coupled INS, GPS, and Imaging Sensors for Precision Geolocation

M. Veth, R. Anderson, F. Webber, M. Nielsen

Abstract:	Recent technological advances have significantly improved the capabilities of micro-air vehicles (MAV). This is evidenced by their expanding use by government, police, and military forces. A MAV can provide a real-time surveillance capability to even the smallest units, which provides commanders with a significant advantage. This capability is a result of the availability of miniaturized autopilot systemswhich typically combine inertial, pitot-static, and GPS sensors into a feedback flight-control system. While these autopilots can provide an autonomous flight capability, they have some limitations which impact their operational effectiveness. One of the primary issues is poor image geolocation performance, which limits the use of these systems for direct measurements of target locations. This poor geolocation performance is primarily a consequence of the relatively large attitude errors characteristic of low-performance inertial sensors. In previous efforts, we have developed a tightly-coupled image-aided inertial navigation system to operate in areas not serviced by GPS. This system extracts navigation information by automatically detecting and tracking stationary optical features of opportunity in the environment. One characteristic of this system is vastly reduced attitude errors, even with consumergrade inertial sensors. In this paper, the benefits of incorporating imagebased navigation techniques with inertial and GPS measurements is explored. After properly integrating GPS with the image-aided inertial architecture, the system is tested using a combination of Monte- Carlo simulation and flight test data. The flight test data was flown over Edwards AFB using representative hardware. The experimental results are compared with validated truth data. The effects of variations in sensor quality and integration methods are investigated and shown to greatly improve the overall performance of the tightly-coupled image-aided sensor over the reference GPS/INS sensor.
Published in:	Proceedings of the 2008 National Technical Meeting of The Institute of Navigation January 28 - 30, 2008 The Catamaran Resort Hotel San Diego, CA
Pages:	487 - 496
Cite this article:	Veth, M., Anderson, R., Webber, F., Nielsen, M., "Tightly-Coupled INS, GPS, and Imaging Sensors for Precision Geolocation," Proceedings of the 2008 National Technical Meeting of The Institute of Navigation, San Diego, CA, January 2008, pp. 487-496.
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