
Synthetic aperture radar (SAR) images, while important in battlefield
analysis estimates, are difficult to interpret. Military assets typically appear as dots
on an image but so do rocks, fence posts, buildings, and other non-military
‘clutter.’ By considering various patterns of dots, the U.S. Army’s Image Exploitation
System (IES) seeks to determine which of these patterns represent military forces.
Furthermore, once such a determination has been made, the system attempts to ascertain
higher level attributes such as force type. Battlefield intelligence includes more than
just SAR images, of course, and this additional intelligence can augment and/or refine the
overall estimate of the battlefield. ELINT is one example. CCR has developed a component
of the IES, called Tactical Elint Analyzer (TEA), to support force estimation based on
ELINT evidence
The modern battlefield is populated by large numbers of non-communications emitters, most
commonly radars. These electronic emitters support a variety of military functions from
air defense to meteorology. However, a single emitter is usually tied closely to a specific
military function (e.g., early warning for air defense). Friendly assets scan the
electromagnetic spectrum ‘listening’ for these non-communications emitters and report
information for each intercept as part of a Tactical Electronic Intelligence (TacElint)
message. TacElint messages typically consist of an estimate of the emitter type, an elliptical
error probable for emitter location, and various electronic attributes, such as frequency,
pulse duration or width, and pulse repetition frequency. TEA combines evidence from TacElint
messages with terrain and doctrinal information to infer the locations and types of forces
present in an area of interest.
TEA responds to an IES request for information about a specific SAR image by first
retrieving relevant ELINT intercepts from an internal database based on location and time.
The intercepts are then self correlated to produce a refined estimate of the number and
position of the various battlefield emitters. TEA uses a terrain based prior probability
to further refine emitter locations. Finally, emitter location estimates are combined with
emitter to force models to predict the disposition of higher level forces in the vicinity.

© Copyright 1998, Commonwealth Computer Research, Inc. All rights reserved.