Ramon Lopez/WASHINGTON DC
The US military is to begin flight tests this year of a device designed to overcome attempts to jam global positioning systems (GPS) over a battlefield, say officials involved in the research and development programme.
The project is part of the US Air Force's extensive navigation warfare programme that is geared to protect the integrity of the satellite-based navigation and positioning signal. An increasing number of US military systems rely on GPS, including precision weapons such as the Boeing Joint Direct Attack Munition and the Lockheed Martin Wind Corrected Munitions Dispenser, as well as the Raytheon Joint Precision Approach Landing System, the US military's next-generation instrument landing system.
The year-old surrogate satellite project, GPS pseudolite, involves the US Defense Advanced Projects Research Agency (DARPA), the USAF's Unmanned Aerial Vehicle Battlelab and US avionics company Rockwell Collins. The latter has completed feasibility studies and built the required GPS pseudolite hardware which is being installed in a Cessna Citation business jet for flight testing in October.
If successful, the lightweight equipment would be installed in an unmanned air vehicle (UAV) for more extensive testing.
As envisioned, the GPS pseudolite using deep antenna nulling would be able to receive low-power GPS satellite signals, despite intensive jamming, and emit a higher-power GPS-like code frequency to receivers modified to work with the surrogate satellite.
The planned UAV test in early 2000 will determine if predictable orbits and timing accuracy can be attained. Jamming would be introduced in a second UAV evaluation in 2001.
Source: Flight International