Sandia National Laboratories has teamed with General Atomics and Sierra Monolithics to develop the Athena tag for
the Army's Radar Tag Engagement (RaTE) program. The radar-responsive Athena tag can be used for Blue Force
tracking and Combat Identification (CID) as well as data collection, identification, and geolocation applications. The
Athena tag is small (~4.5" x 2.4" x 4.2"), battery-powered, and has an integral antenna. Once remotely activated by a
Synthetic Aperture Radar (SAR) or Moving Target Indicator (MTI) radar, the tag transponds modulated pulses to the
radar at a low transmit power. The Athena tag can operate Ku-band and X-band airborne SAR and MTI radars.
This paper presents results from current tag development testing activities. Topics covered include recent field tests
results from the AN/APY-8 Lynx, F16/APG-66, and F15E/APG-63 V(1) radars and other Fire Control radars. Results
show that the Athena tag successfully works with multiple radar platforms, in multiple radar modes, and for multiple
Radar-responsive tags such as Athena have numerous applications in military and government arenas. Military
applications include battlefield situational awareness, combat identification, targeting, personnel recovery, and
unattended ground sensors. Government applications exist in nonproliferation, counter-drug, search-and-rescue, and
Over the past ten years, Sandia has developed RF radar responsive tag systems and supporting technologies for various government agencies and industry partners. RF tags can function as RF transmitters or radar transponders that enable tagging, tracking, and location determination functions. Expertise in tag architecture, microwave and radar design, signal analysis and processing techniques, digital design, modeling and simulation, and testing have been directly applicable to these tag programs. In general, the radar responsive tag designs have emphasized low power, small package size, and the ability to be detected by the radar at long ranges. Recently, there has been an interest in using radar responsive tags for Blue Force tracking and Combat ID (CID). The main reason for this interest is to allow airborne surveillance radars to easily distinguish U.S. assets from those of opposing forces. A Blue Force tracking capability would add materially to situational awareness. Combat ID is also an issue, as evidenced by the fact that approximately one-quarter of all U.S. casualties in the Gulf War took the form of ground troops killed by friendly fire. Because the evolution of warfare in the intervening decade has made asymmetric warfare the norm rather than the exception, swarming engagements in which U.S. forces will be freely intermixed with opposing forces is a situation that must be anticipated. Increasing utilization of precision munitions can be expected to drive fires progressively closer to engaged allied troops at times when visual de-confliction is not an option. In view of these trends, it becomes increasingly important that U.S. ground forces have a widely proliferated all-weather radar responsive tag that communicates to all-weather surveillance. The purpose of this paper is to provide an overview of the recent, current, and future radar responsive research and development activities at Sandia National Laboratories that support both the Blue Force Tracking and Combat ID application. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company for the United States Departments of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.