COTS vs. Custom: Military GIS System Benefits From Best of Both

NASA Tech Briefs, Jul 2006 by Bartch, Dennis

Fast, flexible, portable storage coupled to a pair of Optia 3.4-GHz dual Intel (Santa Clara, CA)EM64T workstations with 800-MHz FSB and an NVidia (Santa Clara, CA) QuadroFX 3400 PCI-e 256MB graphics card makes for a military terrain analyst's "dream machine." That's what Sechan Electronics is building into the latest version of the U.S. Army's Digital Topographic Support Systems - Light (DTSS-L).

DTSS-L is a Humvee-mounted enclosure whose mission is to provide complete and timely three-dimensional map and terrain data, including visibility/line of sight, mobility, and situation-specific query analyses.

The hunger for more storage and faster processing is never-ending when it comes to Geospatial Information Systems (GIS). Largely based on image manipulation, GIS applications are very storage-intensive. The latest configuration of DTSS-L has nearly 7 TB of RAID5 storage, pushing the limits of technology by incorporating the largest hard drives and the fastest, most reliable interfaces.

Sechan Electronics has been producing DTSS-L for the U.S. Army Topographic Engineering Center since 1999 and was recently awarded a multidelivery-order contract that could culminate in production of up to 120 systems valued at $65 million. During the past seven years, Sechan has evolved the DTSS-L design to address changing technology and usability requirements from the U.S. Army user community. Each year brings a fresh shopping list of the latest technology and a new wave of integration issues for the design team.

Drives, Interfaces & Upgrades

U.S. Army officials recently requested Sechan to replace a slow and cumbersome tape library backup system with a group of triple-interface (FireWire 400/800 and USB) portable hard disk drives as part of the latest V7 upgrade. Sechan looked at all major manufacturers of large, portable drives and chose the LaCie (Hillsboro, OR) d2. The d2 drive has a fanless design and extruded alloy housing, which were very desirable features. Fans tend to be high-failure items, especially in dusty environments. The consistency of the LaCie design from one generation to the next was an advantage, and the slotted rail extrusion made it easy to accommodate both in a chassis and on the desktop.

DTSS-L is largely constructed of COTS equipment, so another challenge for Sechan has been to incorporate the latest interface technologies into the harsh military environment. Sechan had to provide a standard and familiar interface that is protected from hostile environments. Electrical protection includes surge protection for USB, FireWire, and video, as well as environmental protection for LAN and USB connectors.

Adequate commercial surge protection products for USB 2.0 and FireWire 800 are almost non-existent, and therefore, a custom solution was developed. A multi-channel USB/ FireWire surge protector was designed based on a combination of low-capacitance transient suppression diodes and gas discharge devices. A video surge protector for standard SVGA signals also was designed. To protect external LAN and USB connections from rain and dust, Sechan selected the Amphenol (Wallingford, CT) RJ Field and USB Field connector series that consists of standard RJ-45 and USB-A type connectors in military circular connector housings. Connectors that are mated and unmated regularly can be a source of system failures even in non-harsh environments, so the goal was to afford the best protection available to improve reliability.

The V7 design of DTSS-L will be the first version using white LED overhead light fixtures in place of incandescent. Gichner Shelter Systems, a Sechan shelter subcontractor, was tasked with finding suitable replacements. They selected dimmable LED fixtures from Oxley (Branford, CT) and are continuing to work with Oxley to refine the product. Sechan was pleased with the results of the prototype testing. The illumination is more uniform throughout the shelter with two of the LED fixtures than what had previously been experienced with three incandescent fixtures, and there was less heat generation. The main benefit is the longevity of LED lamps. A life expectancy of only 300 hours for the incandescent bulbs has been extended to in excess of 20,000 hours for the LED lamps.

The DTSS-L program has ably served the warriors' needs since 2000. In each subsequent year, the system design has changed due to obsolescence of key data-processing equipment, or to include the latest processing and networking technology in support of better software features. The program's success is due in part to the successful combination of COTS equipment, augmented by solutions customdesigned by Sechan.

Sechan Electronics, Lititz, Pennsylvania

This article was written by Dennis Bartch, senior project engineer for DTSS-Light at Sechan Electronics Inc. For more information, contact Mr. Bartch at dbartch@sechun.com or visit http://info.ims.ca/5785421.