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Attitude is the term used to describe the orientation of a rigid body in space and an attitude determination system is used to measure attitude. The attitude information generated by these systems are used in many navigation, guidance and control applications such as pilot-in-the-loop control of manned aircraft, geo-referencing images captured from Uinhabited Aerial Vehicles (UAV), Micro Aerial Vehicles (MAV) or satellite operations.Miniature flying vehicles and satellites require attitude determination systems that are compact (see figure on right), consume very littel power and generate an accurate solution. For example, the figure on the left shows the avionics bay of a small aerial vehicle.
Our research has focused on using multi-sensor approache whereby information from many inexpensive (and possilbe inaccurate) sensors are fused to generate an accurate attitude solution which satisifies the constraints of UAV/MAV or small-satellite applications. These systems are based on fusion of information from inertial sensors (rate gyros and accelerometers), magnetometers, aid data sensors and the Global Positioing System (GPS). For example, the figure below shows the sensor fusion architecture for an attitude determination system designed for a nano-satellite application.
Another aspect of this work has been to adopt ultra-short baseline GPS attitude determination techniques to these applications. The use of GPS as an attitude sensor has been successfully demonstrated. However, on small vehicles such as micro and nano- satellites the space constraints lead to placing the GPS antennas close to each other (i.e. a short baseline). In this configuration, errors that are negligible in large baseline GPS attitude determination applications become significant. We are working on algorithms for in-situ calibration of these errors
Relevant Publication
Gebre-Egziabher, D., R. C. Hayward and J. D. Powell, 2004, Design of Multi-Sensor Attitude Determination Systems, IEEE Transactions on Aerospace Electronic Systems, Vol. 40, No. 2, pp. 627-649, (Journal Article) More Details, Request PDF
Vibhor L. Bageshwar, Demoz Gebre-Egziabher, William L. Garrard, et. al, 2006, Minnesat: GPS Attitude Determination Experiments Onboard a Nanosatellite, 20' Annual AIAA/USU Conference on Small Satellites, , (Conf. Proceeding) More Details, Request PDF
D. Gebre-Egziabher, and G. H. Elkaim, "MAV Attitude Determination from Observations of Earth's Magnetic and Gravity Field Vectors,” to appear in IEEE Transactions on Aerospace Electronic Systems
Last Modified: 2007-08-07 at 11:23:54 -- this is in International Standard Date and Time Notation
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