Airborne systems that use radar to detect, track, and target vehicles moving within a large area of the earth's surface provide extraordinary capabilities. Their use can make obsolete the assumptions regarding information on the location of enemy mobile forces that formerly dominated force structure requirements and concepts of operations. But despite the value of these systems in the Gulf War, Bosnia, Kosovo, and numerous exercises, many U.S. military personnel are not prepared to exploit their immense warfighting potential. To a certain extent, this deficiency can be traced to the unprecedented nature of the systems' capabilities, which require modifying—or discarding—old, familiar ways of thinking and fighting. In the view of British military historian B. H. Liddell Hart, "the only thing harder than getting a new idea into the military mind is to get an old idea out."
Assuming the effectiveness of wide-area, real-time surveillance and targeting systems is limited to flat terrain is an example of outdated thinking. Although mountainous terrain, with its local relief and steep gradients, has much more surface area screened from standoff coverage than flat terrain, these complex variables are not the only factors determining system effectiveness. Other relevant factors include the effect of terrain and weather on vehicular movement, output of surveillance tools and other sensors, and—most important—application of military art and science. When all factors are considered, mountainous terrain actually can increase the contributions wide-area surveillance and targeting systems make to defeating enemy land forces.
Terrain Screening
Because radar beams travel in straight lines, geometry determines the size of areas screened from observation in mountainous terrain. As standoff distance increases, the radar beam's grazing angle (to the earth) decreases and more area is screened from view. The small grazing angles associated with long standoff distances explain why even a 6,000-foot increase in a system's altitude will reduce the size of the screened area slightly, yet often usefully. However, screened areas in mountainous terrain are not static— forward flight makes it possible to look around specific terrain features. The capability is extended when the feature observed is an isolated mountain peak, as opposed to a mountain ridge running parallel to the flight path. The degree to which screening can change with flight depends on the depth and width of the system's coverage, length of an orbit's legs, and standoff distance. For example, typical radar coverage for the Joint Surveillance Target Attack Radar System encompasses plus or minus 600, with ranges from 80 to 250 kilometers.
The same factors that increase screening in mountainous terrain also limit route availability and make movement predictable. Movement often is confined to a single road and it may not be necessary to see movement on all sections of that road to collect valuable information or support effective targeting. In addition, mountainous terrain can make off-road movement difficult or impossible. A lone vehicle's breakdown or damage to the road can stop all movement, thereby exposing the following vehicles to air attack. Other factors—such as road surface load-bearing capabilities, weather, and heavy traffic—can limit vehicular movement, but not the effectiveness of surveillance and targeting systems.
Counters to Screening
A wide variety of measures offer great potential for countering the effect of terrain screening. Orbit optimizers and terrain screening computer tools make it possible to assess screening quickly and precisely and plan orbits that maximize coverage of key road sections. With prior planning, orbits can be varied quickly to provide the best possible coverage of key areas and computer-generated sentinels can be used to automatically notify surveillance system operators of movement. Knowing which areas are screened, and when vehicles are moving in or out of these areas, enables planners to position human ground observers, unmanned ground sensors, and unmanned aerial vehicles (UAVs) to cover them.
Technical tools in development have the potential for further enhancing surveillance and targeting. They could make it possible to analyze vehicular movement by identifying roads used according to predesignated numbers of vehicles, locating vehicle origins and destinations, and finding off-road routes. The effect of screened areas can be reduced by putting obstacles where the terrain favors screening. Their success in impeding or stopping movement can be determined easily by surveillance of even small route sections where there are no alternative routes. If enemy movement resumes, an air or artillery strike could reestablish the obstacle quickly.
Military Skills
Effectiveness of standoff surveillance and targeting systems in mountainous terrain is dependent on a thorough grounding in military science. It is essential that commanders and staffs have a working knowledge of land operations, including familiarity with the critical role of movement in facilitating surprise, superior force ratios, and favorable positioning. They must recognize the extent to which vehicles enhance mobility and can provide armored protection, firepower, and logistic support. Similarly, they must understand the use of air power and how movement affects the targeting process. The dynamics of targeting mobile forces in mountainous terrain demands that commanders decentralize targeting decisions to elements on board surveillance and targeting systems.
Knowledge of military science must be matched by military art, which involves determining when, where, and for what purpose military forces are used. Because warfare involves thinking opponents, it requires great imagination and flexibility; predictability is incompatible with its effective application! Opposing forces are not sets of inanimate objects to be "attrited"—warfare on all levels is dominated by people, most of whom tend to change their behavior based on their perceptions of danger. A premier example of the effective application of military art is joint employment of air and land forces so they complement and reinforce each other to create a powerful synergy. The unprecedented capabilities provided by real-time, wide-area surveillance and targeting systems can cause effects that create an intractable operational dilemma for the enemy: if his units move, they will be seen and targeted; if they disperse and do not move, they will lose their ability to fight effectively.
To create an intractable dilemma in mountainous terrain, planners determine the areas that provide the least screening, locations of enemy and friendly forces, and routes that enemy units are likely to use. This information is then used to force the enemy to move in areas that are most vulnerable to air attack. When the presence of friendly land forces poses a threat or opportunity that the enemy is unlikely to ignore, actual (or threatened) land maneuver probably will cause him to move. Emplaced obstacles will limit movement to vulnerable routes, and alternative routes can be covered with other means of surveillance, such as UAVs. Ideally, air and artillery attacks should be concentrated in areas where enemy forces have no opportunity to disperse—for example, along a narrow road between the side of a mountain and a gorge.
The same surveillance and targeting capabilities that make it possible for air attacks to cause destruction also help to minimize harm to friendly land forces. They can detect developing threats posed by enemy vehicular movement. Early threat detection allows friendly land forces to maneuver to avoid close combat except when they possess overwhelming advantages. By targeting enemy forces, we can either destroy or neutralize them by impeding their movement. While destruction is a key goal, it is not the only one. As Clausewitz noted, "danger is part of the friction of war. Without an accurate conception of danger, we cannot understand war." Successfully creating a perception of intense danger can cause enemy forces to disperse and avoid movement, which allows friendly forces to bypass or overwhelm them with rapid land and air attacks.
Lessons from the Ardennes
The epic Battle of the Bulge demonstrated how to use mountainous terrain to enhance air-power effectiveness against land forces. Although the Allies did not anticipate a major attack, they could not have chosen a better place to be attacked than the Ardennes. The widespread forests, rough terrain, and narrow, steep-sided gorges restricted German tracked and wheeled vehicles to a limited number of narrow roads. And the same weather that initially prevented air attacks also saturated the terrain, making cross-country movement virtually impossible in many areas.
The German offensive began to bog down in Belgium because the restricted routes and rugged terrain gave Allied land forces valuable defensive advantages. When the weather improved, road-bound German forces presented the classic target-rich environment. Allied air attacks quickly crippled their advance and prevented resupply and reinforcement. Field Marshall Model forbade German daylight movement, noting that, "On the entire front there was the heaviest enemy lowflying attacks. . . which made movement and supply on the battle field nearly impossible." Lack of supplies, combined with German perceptions of danger from air attacks, soon caused many of them to abandon their vehicles and withdraw on foot. The elite Panzer Lehr Division left behind 53 tanks and assault vehicles.
If the Battle of the Bulge were fought again—with the only change being availability of today's wide-area, real-time surveillance and targeting systems—U.S. forces would blunt the German offensive much faster and at less cost. The farseeing eyes of these systems would make air power considerably more efficient at finding and destroying German forces. It would allow Allied land forces to maneuver more effectively, thus greatly reducing the need for close combat.
Conclusions
Retired Army General John Tilleli, former commander of U.N. and U.S. forces in Korea—a country characterized by mountainous terrain—said that "one of the first assets" he requested in crisis situations on that peninsula was a wide-area, real-time surveillance and targeting system. It was "an invaluable tool" that could tell him "where the enemy is, where they're not, and where they're moving to."
The conflict in Afghanistan makes clear that U.S. forces must know how to use airborne surveillance and targeting systems to best advantage. Realizing the full potential of these systems depends on people who are knowledgeable in military science and versed in applying military art at the tactical and operational levels of war. Ensuring this will require intensive, "high-fidelity" war gaming, realistic joint training—and full awareness of the challenges posed by mountainous terrain.
Colonel Bingham, a former fighter pilot, contributed to writing basic doctrine for the Air Force. He is now a business development manager with Northrop Grumman Corporation in Melbourne, Florida.