United States Department of Defense United States Department of Defense

News Release

Press Operations Bookmark and Share

News Release


Release No: 676-96
December 18, 1996


The Defense Advanced Research Projects Agency (DARPA) Tactical Technology Office (TTO) and the Naval Air Systems Command (NAVAIR) Air Combat Electronics Program Office (PMA-209) today announced the successful completion of a joint flight demonstration of an advanced navigation set on an F/A-18. Personnel from the Naval Air Warfare Center, Aircraft Division (NAWCAD), Patuxant River, Md., provided engineering and integration of the navigation set into the aircraft. They also provided the aircraft itself and the ground and flight crews. Flight testing was conducted Nov. 26 - Dec. 17, 1996.

DARPA provided a Phase 1 Global Positioning System (GPS) Guidance Package (GGP) for the tests. The GGP consists of a miniature inertial navigation set (INS), a 10-channel receiver capable of processing GPS precision position service signals and a navigation computer. The GPS receiver and INS are tightly coupled, which allows them to aid each other, depending on GPS signal conditions and the air alignment mode.

The objectives of the flight demonstrations were threefold: to demonstrate GGP performance under highly dynamic conditions (e.g., 7.5g acceleration); to demonstrate the advantages of a tightly coupled architecture; and to demonstrate various modes of operation. The modes include blended GPS/INS navigation; inertial-only navigation, simulated periodic jam-out of GPS signals and inflight alignment of the INS.

For the tests, the GGP was mounted in the nose of the F/A-18 and a single GPS antenna was mounted on the top of the aircraft. Instrumentation included data recording equipment and a differential GPS reference receiver for ground truth. Recorded data enabled the calculation of GGP performance in position, velocity, and GPS satellite tracking.

Prominent among the flight profiles were a diamond pattern and simulated bombing and combat maneuvers, e.g., air-to-air combat. The diamond profile had relatively long legs and

tested both blended GPS/INS and INS-only navigation. The bombing and combat maneuvers included up to 7.5g turns and rapid changes in altitude and airspeed. Barrel rolls, Immelmans and split maneuvers were included in some flights. This took the top- mounted GPS antenna out of line-of-sight to GPS satellites. The high value of tightly coupled INS aiding was thus demonstrated. The INS navigated when the GPS receiver had no signals, and enabled reacquisition of GPS signals within seconds once the aircraft rolled level.

The DARPA GGP program manager, Air Force Lt. Col. Beth Kaspar, said, The flight tests really put the GGP through its paces -- one of our so-called benign flights had barrel rolls and touch-and-goes. We certainly met our demonstration goals, especially in showing the value of tight coupling and navigation in high dynamics conditions. I have high praise for the splendid cooperation and performance by all Government and industry participants.

GGP Phase 1 was developed under DARPA sponsorship by Litton Industries, Woodland Hills, Calif., and Rockwell International Collins Avionics and Communications Division, Cedar Rapids, Iowa. The program is now in its second phase, during which navigation performance will be increased, and size, weight and power will be significantly reduced. Litton Industries and Honeywell Inc. are leading the teams competing in the Phase 2 development phase.

Additional Links

Stay Connected