本帖最后由 post2007 于 2013-5-7 07:58 编辑
[美]兰德公司:未来部队的高纬度飞艇
High-Altitude Airships for the Future Force Army
Abstract : Across the services, there is an increasing demand for overhead communications capacity. For the U.S. Army, this is a result of its transition to a new force structure that will be knowledge-based and network-centric. Future forces may be more dispersed. Extending their range of communication will be key. Messages will have to be relayed through a multilayered network of terrestrial-, air-, and space-based retransmission nodes. Currently, satellite communications (SATCOM) is being relied on to connect distant units. However, the exclusive use of military or commercial SATCOM may not be available to meet all of the Army's connectivity needs, and high-altitude airships (HAAs) are being considered as an optional surrogate, which could be even more cost-effective if proved technically feasible. New, lighter-than-air (LTA) vehicles that operate at very high altitudes have an obvious attraction for planners of surveillance and communication missions; the ability to see to a more distant horizon results in greatly expanded surveillance volumes (assuming that appropriately powerful sensors are carried onboard). Low probability of intercept (LPI) direct line-of-sight communications will also increase their reach. In recent years, increased emphasis has been placed on systems that can provide extended surveillance and communications support at such high altitudes. These are generically known as High Altitude Long Endurance (HALE) systems or High Altitude Long Loiter (HALL) systems. The Global Hawk unmanned aerial vehicle (UAV) was perhaps the first of these systems to achieve operational success. Flight at high altitude (say, over 60,000 feet) for extended periods (for a matter of days or more) is an extreme technical challenge for fixed-wing aircraft. The purpose of this report is to inform the U.S. Army about the usefulness and limitations of airships in roles of supporting communications and surveillance functions in theater battlespace.