TABLE OF CONTENTS Radar has been called the greatest advance in sensing remote objects since the telescope was invented in 1608 [1]. Electronic intelligence (ELINT) is the result of observing the signals transmitted by radar systems to obtain information about their capabilities: it is the remote sensing of remote sensors. Through ELINT, it is possible to obtain valuable information while remaining remote from the radar itself. Clearly, ELINT is most useful in hostile situations; otherwise, the information could be obtained directly from the radar user or designer. The value of ELINT is that it provides timely information about threatening systems, such as radars that guide aircraft or missiles to targets. ELINT also provides information about defensive systems, which is important in maintaining a credible deterrent force to penetrate those defenses.
ELINT refers to the information gained from the interception of signals of interest. In addition to radar, other types of signals referred to as sources of ELINT include beacons and transponders, jammers, missile guidance, some data links, altimeters, navigation emissions, and identification friend or foe (IFF). In this broad sense, ELINT can refer to nearly any noncommunications emission. This book is concerned largely with ELINT derived from radar signals.
Receiving radar signals is often not difficult because the available power density is quite high. The power transmitted by a radar is proportional to the fourth power of the range at which it is to detect a target; whereas the power available at an ELINT receiver is proportional to...
