An Overview of a Global Positioning System Mission Planner Implemented on a Personal Computer

Paul G. Avila, Steven N. Karels, Thomas J. Macdonald, Gary A. Matchett, Iris P. Roberts, Vance Gloster

Abstract:	A Global Positioning System (GPS) Mission Planner (GMP) tool which has been implemented on an IBM PC is described in terms of its features and architecture, and sample outputs are presented. The GMP was written to permit operational units to plan missions and to accomplish survivability and navigation assessments based on realistic trajectories, GPS almanac data. broadband jammer specifications. and Digital Terrain Elevation Data (DTED). The GMP was required to operate on a Zenith Z-248 PC (or equivalent)with 2 tloppy disk drives, EGA graphics, 640KBytes of RAM memory, and either a color or monochrome graphics monitor. GMP supports trajectory generation for generic air,land. or naval vehicles and has "sanity"" checks for altitude. acceleration. terrain slope, and velocity limits. A survivability measure is computed based on exposure time to various threat types. "Yuma-type" almanac data are used to support the G MP to define GPS satellite orbits. Jammers. threats. and trajectory waypoints may be defined by either keyboard entry (e.g .. longitude, latitude, and altitude) or via mouse and cursor on a displayed pseudo-color DTED map on the PC monitor. Satellite visibility and best Dilution-of-Precision (DOP) are computed using DTED. Jammer visibility and power levels at the vehicle are similarly computed. A realistic body masking and antenna gain model- based on the Fixed Radiation Pattern Antenna (FRPA) - is employed to compute carrier-to-noise densities for each visible satellite. A navigation assessment program emulates a multichannel receiver to generate position and velocity measurement uncertainties. An integrated Kalman filter generates position and velocity navigation estimates using a generic inertial measurement unit (IMU) and the GPS receiver measurement statistics. Results are graphically displayed to the operator so that overall navigation and survivability requirements can be assessed, and the mission revised accordingly. Sample results from a representative scenario are included. Lessons learned in developing a PC-based mission planning tool are also discussed.
Published in:	Proceedings of the 45th Annual Meeting of The Institute of Navigation (1989) June 27 - 29, 1989 Alexandria, VA
Pages:	179 - 187
Cite this article:	Avila, Paul G., Karels, Steven N., Macdonald, Thomas J., Matchett, Gary A., Roberts, Iris P., Gloster, Vance, "An Overview of a Global Positioning System Mission Planner Implemented on a Personal Computer," Proceedings of the 45th Annual Meeting of The Institute of Navigation (1989), Alexandria, VA, June 1989, pp. 179-187.
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