After several years in development, the Blackjack version of GPS from the U.S. Defense Advanced Research Projects Administration (DARPA) is taking on more of its low-earth-orbit satellite (LEOS) form. Initiated several years ago as part of a contract with Lockheed Martin Corp., DARPA is now looking to Northrop Grumman Corp. to enhance the LEOS-based GPS technology and make it more resistant to jamming. GPS signals emitted from lower orbits are subject to jamming from even low-cost, commercial-off-the-shelf (COTS) electronic equipment and the Blackjack program was begun to explore the possibility of using LEOS rather than geostationary-earth-orbit satellites (GEOS) for GPS service. LEOS are smaller, requiring less power to launch and with less signal transmit/receive latency between the satellite and earth. However, LEOS provide less coverage area than a GEOS; a greater number of orbiting LEOS than GEOS is needed for the same coverage area. A constellation of LEOSs would minimize the impact of single-point failures that can occur in GEOS constellations.
The DARPA contract (valued at $13.2 million) to Northrop Grumman is for Phase 2 development of a software-defined positioning, navigation, and timing (PNT) payload for the LEOS. The payload work is being formed by Northrop Grumman’s Future PNT Systems Operating Unit (Woodland Hills, CA), with the goal of achieving affordable national-security space capabilities based on LEOS. The PNT payload (see the figure) will include Northrop Grumman’s Software Enabled Reconfigurable Global Navigation Satellite System (GNSS) Embedded Architecture for Navigation and Timing (SERGEANT) capability.
“Northrop Grumman’s software-defined positioning, navigation, and timing technology will offer military users an agile new signal from LEO that is not dependent on existing satellite navigation systems,” said Dr. Nicholas Paraskevopoulos, chief technology officer and sector vice-president for emerging capabilities development at Northrop Grumman Corp. “Warfighters depend on assured PNT for traditional missions like force projection and joint operations, but also for emerging autonomous and distributed missions.”