Complex “terrain.” Heavy combat in cities and large towns generates a chaotic artificial terrain. The lack of a clear line of combat as well as the presence of dust and smoke can make identification of combatants difficult or impossible. Combatants can easily remain hidden until detailed searches, lasting many days, are completed.
Short line of sight. Urban combat occurs in an environment of extremely short lines of sight. Intense firefights between neighboring rooms in a housing unit, for example, are characterized by short range and a common element of surprise. Reaction time is very short, and positive identification may be possible only ex post facto.
Intermixing of noncombatants (noncombatants) and combatants. When population densities are high, it is impossible to rule out the presence of significant numbers of noncombatants. In many cases these people are the most vulnerable of the former population, since it is hardest for them to leave the combat zone quickly. This situation makes it difficult for troops to engage enemy troops without fear of incurring casualties among noncombatants.
Need for precision delivery of weapons. Because of the short distances, complex terrain, and mixing of targets, urban combat requires the ability to deliver ordnance with precision so that collateral damage is minimized. This capability is compromised if noncombatant or RED team identification is spoofed.
One form of misidentification relates to the issue of fratricide, which in itself is very challenging and has been addressed in other studies. A report from the Office of Technology Assessment entitled Who Goes There: Friend or Foe? discusses the Persian Gulf War and the problem of fratricide. During that conflict, 24 percent of U.S. combat fatalities were due to friendly fire (U.S. Congress, OTA, 1993). There is an optimal level of antifratricide measures beyond which more stringent measures could lead to increased losses from enemy fire owing to slow reaction times. The four pillars of fratricide prevention are doctrine, training, rules of engagement, and technology, as viewed from a BLUE force perspective (Armstrong, 1999). While related to the topic at hand, the avoidance of fratricide is not the central focus of the committee in this chapter; its focus instead is on the capability of discriminating between enemy combatants and noncombatants.
Rules of engagement from a RED force perspective include causing confusion, hiding among the noncombatant population in areas not necessarily designated as combat zones, jamming electronic devices, and moving so that prior reconnaissance or mapping by the BLUE force is of limited utility. When cast in the context of urban warfare, the scenarios become even more complex, if only because noncombatants must also be positively identified to avoid harming them.
The techniques for the identification of noncombatants in combat areas are stressed to the limit in urban warfare, principally because of the short timescale of combat and the possibility that large numbers of noncombatants might be present. Spoofing of sensors, including both visual and electronic imaging systems, compromises the BLUE force’s ability to carry out precision engagements and may endanger noncombatants. Recent examples of urban combat have included the use of noncombatants as shields by enemy combatants. Finally, ground-to-ground combat even under the best of circumstances is prone to error; the fratricide rate during Desert Storm was 69 percent attributable to ground-to-ground combat (U.S. Congress, OTA, 1993). Urban environments further exacerbate the challenge relating to the discrimination of combatant forces.