GPS control of Flexible Structures

Faculty Contact: Jonathan How

Based on the research of Harris Teague for his Ph.D.

The objective of this project was to determine the applicability of GPS as a deformation sensor for structures in space. A test structure has been built which is about 30 ft long and about 500 lbs. which is suspended from vertical support threads. The dynamics of the structure are analogous to an orbiting structure which exhibits large deflections at low frequencies.

We have demonstrated 10 Hz differential carrier phase measurements during free vibration of the model. Six rate gyroscopes have been mounted on the structure and are being used as a verification of the GPS sensor accuracy. We have developed a dynamic model and a state-estimator that are used in real-time feedback control of these motions. Both vibration suppression and slew maneuvers control have been achieved. The actuators are on-off cold gas jets.

* Some pictures


3D CAD image of block

Gyros used for calibration

Transmit antenna

Receive antennas and actuators

Suspension system

Overhead view of the test structure

The GPS hardware

Structure in motion

* Papers

E. Harrison Teague, Jonathan P. How, Bradford W. Parkinson, "Control of Flexible Structures using GPS: Methods and Experimental Results", as published in the AIAA JGCD. Download (500kB)

E. Harrison Teague, Jonathan P. How, Bradford W. Parkinson, "Carrier Differential GPS for Real-Time Control of Large Flexible Structures," Proc. of the Institute of Navigation GPS-96 Kansas City, MO, September 1996. Download (200kB)

E. Harrison Teague, Jonathan P. How, London G. Lawson, Michael Boerjes, Bradford W. Parkinson, "Techniques for Real-Time Control of Flexible Structures Using GPS," Proc. of the AAS Guidance, Navigation, and Control Conference Breckenridge, CO, February 1996. Download (312 kB)

E. Harrison Teague, Jonathan P. How, London G. Lawson, Bradford W. Parkinson, "GPS as a Structural Deformation Sensor," Proc. of the AIAA Guidance, Navigation, and Control Conference, Baltimore, MD, 1995. Download (911 kB)