About the Author David Y. Hsu is currently a member of the Senior Technical Staff with the Advanced Systems Analysis Group at Litton Guidance and Control Systems Division. Since 1982, his principal tasks have included gravity modeling/compensation, simulation, and analysis. He has authored over 20 scientific articles in the ION, IEEE Plans, NAECON proceedings, and other Mathematical/Engineering journals. Dr. Hsu received his B.S.E.E. from the National Taiwan University and his Ph.D. in Applied Mathematics from the University of Virginia. He has taught in the Electrical Engineering, Mathematics...