GPS Attitude Determination

Research is being performed to develop new and efficient algorithms for attitude determination using Global Positioning System signals. The goal of this research is to develop fully autonomous algorithms that are robust for any initial attitude. Specific issues to be addressed in the research include:

• Provide optimal attitudes even for coplanar baseline configurations
• Guarantee convergence even for poor initial conditions
• Develop computationally efficient algorithms

At the NASA-Johnson Space Center (JSC), in the Navigation Systems & Technology Laboratory (NSTL), work commenced to demonstrate the use of an indoor pseudolite "constellation" to enable relative attitude determination. Pseudolites, which are radio-frequency transmitters that emit signals similar to the GPS transmissions, are a technology that has become increasingly familiar in the past decade. While pseudolites are still a developing technology, which have not yet been demonstrated in an on-orbit space flight experiment, it is perceived that they hold great promise for augmenting the existing GPS satellite-based navigation and attitude determination technology in local-area applications. The goal of this research is to investigate and develop optimal algorithms that can provide fast and reliable relative attitude information of a moving vehicle.

This work is sponsored by NASA-Johnson Space Center. Results from research can be obtained from: Park, K., and Crassidis, J.L., “A Robust GPS Receiver Self Survey Algorithm,” Navigation: Journal of the Institute of Navigation, Vol. 53, No. 4, Winter 2006, pp. 259-268.

[1] Park, K., and Crassidis, J.L., “Attitude Determination Methods Using Pseudolite Signal Phase Measurements,” Navigation: Journal of the Institute of Navigation, Vol. 53, No. 2, Summer 2006, pp. 121-134.

[2] Crassidis, J.L., and Lightsey E.G., “Attitude Determination Using Combined GPS and Three-Axis Magnetometer Data,” Space Technology, Vol. 22, No. 4, 2001, pp. 147-156.

[3] Crassidis, J.L., Lightsey, E.G., and Markley, F.L., “Efficient and Optimal Attitude Determination Using Recursive Global Positioning System Signal Operations,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 22, No. 2, March-April 1999, pp. 193-201.

[4] Crassidis, J.L., Lisano, M., and Lightsey, E.G., “Autonomous Attitude Determination for ISS Applications Using Pseudolite Signals,” Proceedings of the AIAA International Space Station Service Vehicles Conference, Houston, TX, April 1999.

[5] Crassidis, J.L., Markley, F.L., and Lightsey, E.G., “Application of Vectorized Attitude Determination Using Global Positioning System Signals,” Proceedings of the AIAA/AAS Astrodynamics Specialist Conference, Boston, MA, Aug. 1998, AIAA Paper #98-4390.

[6] Crassidis, J.L., and Markley, F.L., “New Algorithm for Attitude Determination Using Global Positioning System Signals,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 20, No. 5, Sept.-Oct. 1997, pp. 891-896.

[7] Crassidis, J.L., Markley, F.L., Lightsey, E.G., and Ketchum, E., “Predictive Attitude Estimation Using Global Positioning System Signals,” Proceedings of the Flight Mechanics/Estimation Theory Symposium, NASA-Goddard Space Flight Center, Greenbelt, MD, May 1997, pp. 107-120.

[8] Lightsey, E.G., Ketchum, E., Flatley, T.W., Crassidis, J.L., Freesland, D., Reiss, K., and Young, D., “Flight Results of GPS Based Attitude Control on the REX II Spacecraft,” ION-GPS-96, Kansas City, MO, Sept. 1996, pp. 1037-1046.

Integer Ambiguity Resolution

Research is being performed at NASA-Johnson Space Center (JSC), in the Navigation Systems & Technology Laboratory (NSTL), to develop optimal algorithms for integer ambiguity resolution using Global Positioning System signals. The goal of this research is to develop fully autonomous algorithms that are attitude independent. Specific issues to be addressed in the research include:

• Sequentially estimate the ambiguities during the vehicle motion
• Provide inherent integrity checks
• Provide optimal attitudes even for coplanar baseline configurations

This work is sponsored by NASA-Johnson Space Center. Results from research can be obtained from:

[1] Lightsey, E.G., and Crassidis, J.L., “Real Time Attitude Independent GPS Integer Ambiguity Resolution,” The Journal of the Astronautical Sciences, Vol. 52, Nos. 1-2, Jan.-June 2004, pp. 251-267.

[2] Lightsey, E.G., and Crassidis, J.L., “Real Time Attitude Independent GPS Integer Ambiguity Resolution,” The John L. Junkins Astrodynamics Conference, College Station, TX, May 2003, AAS Paper #03-266.

[3] Lightsey, E.G., Crassidis, J.L., and Markley, F.L., “Fast Integer Ambiguity Resolution for GPS Attitude Determination,” AIAA Guidance, Navigation, and Control Conference, Portland, OR, Aug. 1999, AIAA Paper #99-3999, pp. 403-412.

[4] Crassidis, J.L., Markley, F.L., and Lightsey, E.G., “Global Positioning System Integer Ambiguity Resolution Without Attitude Knowledge,” AIAA Journal of Guidance, Control, and Dynamics, Vol. 22, No. 2, March-April 1999, pp. 212-218.