Rethink. This is an ongoing theme for proven military technologies in the face of evolving and expanding threats. Modern fighter aircraft pilots are among the most highly trained and skilled professionals in the world. Yet, they face a very real danger from increasingly sophisticated shoulder-launched weapons that can be operated by nearly anyone. Ground forces face another set of challenges on the battlefield, where advanced radio equipment available on the open market makes “RF supremacy” difficult to achieve. Also, as war fighting becomes increasingly multifaceted, rapidly planning, deploying and coordinating attack forces becomes a major challenge with its own risk of casualties apart from encounters with the enemy. To address these and other vulnerabilities, designers must constantly strive to improve the effectiveness and robustness of military systems. As will be shown in the features that follow, one way this can be accomplished is by rethinking the existing techniques or system architectures of mature systems.

The basic technique of data recovery in digital communications networks can be improved with a new packet-based recovery method, which is superior to the recovery methods of the past that merely corrected bit-level errors. Furthermore, this new method can be implemented in software and executed on general-purpose hardware, which is in keeping with trends in the radio equipment to which it may be interfacing in the future. This technology can also be used in conjunction with any other mode of digital communication, such as wire-based links, and operates transparently with encrypted or unencrypted data.

In Alan Jacobsen's article, “Military Communications and DF Raptor,” the potential for this new data recovery technology from Digital Fountain is made clear. Whether due to the elements or to hostile jamming, DF Raptor compensates for the challenges faced by increasingly complex military communications systems.

Shifting to the power supply side of equipment, designers will gain exposure to a set of hybrid dc-dc converters that can be used to improve the efficiency and reliability of conventional power bus architectures. While 28 V bus architectures that employ direct conversion to a desired voltage may conform to military requirements, compliance is often achieved at the expense of conversion efficiencies falling well below industry standards. A high-efficiency reliability optimized (HERO) power system using these hybrid converters provides high reliability and high efficiency by blending direct conversion and post regulation into an optimal distributed power architecture. VPT's Steve Butler in “Point-of-Load Power Solutions for Low-Voltage Applications,” provides a detailed analysis of this approach. The resulting increase in efficiency not only extend the effectiveness of energy-constrained systems, it can also reduce costs and extend reliability by reducing thermal management requirements.

Another military technology that is being re-evaluated is air traffic surveillance radar. Quite simply, the growing amount of air traffic is straining the capacity of the present air traffic control radar beacon system (ATCRBS). A new way to interrogate an airframe, called mode S, uses an address to which only one uniquely pre-assigned aircraft will respond. The result is greatly improved radar system capacity, and greatly reduced confusion in aircraft identification. Along with this ability to precisely interrogate individual aircraft, this system enables large amounts of critical data to be exchanged between the ground and the air as well as between individual aircraft. Where surveillance radar once provided specific identification of an aircraft, it can now also be used to identify the intentions of the pilot. For example, the pilot of an aircraft that is holding a steady course on radar may actually be planning to change course or altitude. With mode S, this information would be available for processing along with the conventional data normally transmitted in reply to an interrogation by the surveillance radar. In effect, the radar, once an instrument for extending spatial situational awareness, can now extend a controller's temporal situational awareness. Wes Stamper of Aeroflex gives a thorough overview in “Understanding Mode S Technology,” which is a discussion about mode S basic, elementary and enhanced surveillance, DF17 extended squitter and ADS-B. These advances will benefit both general and military aviation, and the article will certainly provide much food for thought on your next commercial flight.