Control of Flexible Structures Using GPS: Methods and Experimental Results

Active control of the attitude and vibration of a e exible structure using the Global Positioning System (GPS) is demonstrated. Measurements of the carrier phase of the GPS signal at several antennas are used to estimate the deformation and orientation of the structure. This distributed measurement capability, combined with excellent zero-frequency performance, makes the GPS sensor an excellent choice for a wide range of applications, including space structures, suspension bridges, and skyscrapers. The control system developed around the GPS sensor is presented for a particular structure modeled after the Space Station. The results from several new experiments demonstrate that the GPS sensor provides rotational accuracies better than 0.1 deg for static tests. Measured spectra also demonstrate that the carrier-phase GPS techniques are sufe ciently accurate to resolve many of the modes of vibration. Several feedback control experiments are used to show that the sensor provides an accurate and robust measure of the structural deformations. These experiments culminate in a fast slew maneuver under feedback control, which providesa cleardemonstration oftheapplication of carrier-phaseGPS forboth alignment and vibration control. This work shows the potential for GPS as a high-precision, real-time structural sensor.

[1]  Penina Axelrad,et al.  Spacecraft attitude estimation using the Global Positioning System - Methodology and results for RADCAL , 1996 .

[2]  E. Glenn Lightsey,et al.  The GPS Attitude Determination Flyer (GADFLY): A Space-Qualified GPS Attltude Receiver on the SSTI-Lewis Spacecraft , 1995 .

[3]  Huibert Kwakernaak,et al.  Linear Optimal Control Systems , 1972 .

[4]  Jonathan P. How,et al.  CARRIER DIFFERENTIAL GPS FOR REAL-TIME CONTROL OF LARGE FLEXIBLE STRUCTURES. , 1996 .

[5]  Bradford W. Parkinson,et al.  Application of GPS Attitude Determination to Gravity Gradient Stabilized Spacecraft , 1993 .

[6]  Arthur Gelb,et al.  Applied Optimal Estimation , 1974 .

[7]  Bradford W. Parkinson,et al.  Carrier-Phase DGPS for Closed-Loop Control of Farm and Construction Vehicles , 1996 .

[8]  Kurt Ronald Zimmerman,et al.  Experiments in the use of the global positioning system for space vehicle rendezvous , 1996 .

[9]  Alan G. Evans,et al.  Using GPS to Determine Vehicle Attitude , 1988 .

[10]  Richard W. Longman,et al.  Active Control Technology for Large Space Structures , 1993 .

[11]  Bradford W. Parkinson,et al.  GPS Based Attitude Determination On Nonaligned Antenna Arrays , 1996 .

[12]  Michael S. Braasch,et al.  GPS Interferometric Attitude and Heading Determination: Initial Flight Test Results , 1991 .

[13]  Alan G. Evans,et al.  Using GPS to Determine Vehicle Attitude: USS Yorktown Test Results , 1989 .

[14]  Bradford W. Parkinson,et al.  FLIGHT TESTS OF ATTITUDE DETERMINATION USING GPS COMPARED AGAINST AN INERTIAL NAVIGATION UNIT. , 1994 .

[15]  Bradford W. Parkinson,et al.  Origins, Evolution, and Future of Satellite Navigation , 1997 .

[16]  Edward Harrison Teague,et al.  Flexible structure estimation and control using the global positioning system , 1997 .

[17]  Bradford W. Parkinson,et al.  Real-Time CDGPS Initialization for Land Vehicles Using a Single Pseudolite , 1997 .

[18]  Dean W. Sparks,et al.  Survey of experiments and experimental facilities for control of flexible structures , 1992 .

[19]  Bradford W. Parkinson,et al.  AUTOLANDING A 737 USING GPS INTEGRITY BEACONS , 1995 .

[20]  Bradford W. Parkinson,et al.  Maintaining GPS Positioning in Steep Turns Using Two Antennas , 1995 .

[21]  Jonathan P. How,et al.  Robust control design and implementation on the Middeck Active Control Experiment , 1994 .

[22]  Bradford W. Parkinson,et al.  Translation, rotation, and vibration control of large space structures using self-differential GPS (SDGPS) , 1993 .

[23]  P. Axelrad,et al.  SNR-based multipath error correction for GPS differential phase , 1996, IEEE Transactions on Aerospace and Electronic Systems.