by Paul Beshenich
The American Competitiveness Institute (ACI), under direct support of the U.S. Army CECOM and in partnership with the U.S. Navy and joint DoD program offices, are collaborating with industry partners to redesign the Air Radio Set (ARS-6). This radio is used by military aircraft for conducting search and rescue missions to locate personnel equipped with PRC-112 survival radios. The Open Architecture’s non-custom, proprietary redesign effort will reduce cost, improve both reliability and supportability, and include new feature upgrades such as the Global Position System (GPS) currently being designed into the next generation military radios.

Background:
The AN/ARS-6 Radio Set is the airborne part of a system for Combat Search and Rescue (CSAR). The system includes a handheld radio (responder) that addresses a Personnel Locator Set (PLS). The AN/ARS-6(V) Radio Set is the essential airborne component of the PLS, and provides the rescue team with the identification, direction, and distance to the responder radio. (See Figure 1)
Together, the responder radio and the AN/ARS-6 Radio Set are the standard CSAR system for the U.S. Army, Navy, Air Force and NATO. The airborne guidance system covertly and precisely locates downed or missing pilots - in a single pass under harsh operating conditions - while concealing the war fighters’ location from the enemy.

The existing AN/ARS-6 Radio Set is a unique, custom design composed of the following components: control display unit, antenna switching unit, receiver/trasmitter, mounting base, remote display unit, antenna set.

The cost of sustaining this system is expensive, and is considered excessive by the government.

Current Status & Areas for Improvement:
Field maintenance of the AN/ARS-6 Radio Set is limited to task categories at the operator's Aviation Unit Maintenance (AVUM) and the Aviation Intermediate Maintenance (AVIM) levels. In essence, this permits only exchange of Line Replaceable Units (LRUs), and excludes any attempt to repair these units in the field. For repair, the LRUs are returned to the U.S. Army Depot at Tobyhanna, Pennsylvania (TYAD).

It is now necessary to upgrade the obsolete electronics of the ARS-6 system. Replacement of the outmoded through-hole technology of these modules with state-of-the-art surface-mount technology does decrease the cost of these modules, overcomes the increasing problems of component obsolescence, and miniaturizes the systems with concurrent savings in both weight and space. This creates the opportunity for the addition of increased functionality into the AN/ARS-6 Radio Set, such as inclusion of integrated GPS capabilities.

Re-Design Packaging:
To mitigate the current maintenance and repair problems of the AN/ARS-6 Radio Set, while substantially decreasing both the initial and lifetime cost of operation, the American Competitiveness Institute (ACI) has initiated the following engineering re-design approach:

1. Implement an Open Architecture re-design for the ARS-6 using COTS components/modules, and base it on industry standards with interface specifications that are public domain instead of proprietary, or "closed" custom designs.

2. Top level system design identifying the COTS modules and dividing the RF and control sections. Through the use of high level building blocks, such as a single board computer, power supply module, RF power amplifier, low noise amplifier, RF relay, splitter, and even the use of major portions of the existing PRC-112 and developing CSEL survival radios themselves, the need to do low level detailed design is greatly diminished. Also, in the event of a component or module obsolescence issue, this open architecture design concept permits relatively easy replacement of the COTS module rather than a complete redesign.

3. Software simulation of the system to ensure that all requirements and functional specifications are satisfied per the system document.

4. The ARS-6's new software will be developed for a COTS single board computer based on a standard operating system. This effort will require code for both operational control of the unit as well as diagnostic and test routines. Again, as with the COTS hardware modules, the objective is to write the code with a well documented Open Architecture that is readily understood and maintainable by an average skill-set programmer.

Re-Design Goals:

• Reduced cost (goal of < $25K) alternative ARS-6+ Receiver-Transmitter module. Modern COTS sub-assemblies and displays will provide more durable and affordable alternatives to those
  currently spefied, while fully matching the current display and ARS-6 system in function. It should be noted that defective displays are the most frequent LRU returns to the depot.
• Redesign of the RT-1532 Receiver-Transmitter. These RCM and SPM Module boards currently use outmoded through-hole mounting technology. The redesign will use state-of-the-art COTS surface-mount components and modules, allowing cost improvement through improved maintenance capabilities, avoidance of obsolescence problems, and miniaturization for weight nd space savings that allow incorporation of additional functionality such as GPS capability. (See Figure 2)
• Expand the self-diagnostic capabilities integral to the ARS-6+ by incorporating additional algorithms to identify not only the disabled LRU, but also the site of failure within the LRU. This information will greatly facilitate the troubleshooting operations at the depot and further reduce the quantity of LRUs that must be returned to the contractor for replacement.

A bench-top redesigned ARS-6+ open architecture system will be developed and tested at ACI. It will then be provided to the Tobyhanna Depot for functional testing and evaluation before proceeding to the next stage of developing Air Worthiness Release qualification prototype hardware.

For more information regarding the ARS-6 Open Architecture program at ACI, please contact the Helpline at (610)-362-1320.