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Wireless Communications at Home on the (Firing) Range
U.S. military range in Fort Carson, CO puts wireless technology through its paces
Design News Staff -- Design News, October 13, 2009
Weidmüller's customer, Meggitt Training Systems Inc. (MTSI), is part of Meggitt PLC, an organization that provides training systems used by militaries, law enforcement and security agencies around the world. Meggitt designed and installed one of the most advanced live fire ranges ever provided to the U.S. military, in Fort Carson, CO. This digitally controlled, heavy armor range is comprised of 14 moving targets located across a 60 sq km (23.2 sq mile) area. Each of the targets includes one bunker location and a separate remote vehicle or mover. The reinforced concrete bunkers contain the technology, including a wireless Ethernet modem, to operate the movers.
The 3,000-lb mover is mounted onto a raised metal track and has four lift arms that move the target, which is a silhouette of an armored vehicle. A control box located on the mover contains another wireless modem and the circuitry to operate the drive motors and the lift arms of the vehicle. The tracks vary in length, depending on the range. Each of the 14 moving target ranges is controlled via Ethernet signals from a central Range Operations Center (ROC).
Problem
Meggitt faced two major problems at the Fort Carson, CO range. The first challenge was environmental. Operating conditions on a live fire, heavy armor range are not favorable to electronic equipment — especially highly sensitive, high-technology wireless devices. The temperature inside the control box on each mover varies from -40C (-40F) in winter to 65C (149F) in summer. In addition, operating on a range with tanks firing live ammunition necessitated a wireless device that withstands shock and vibration.
The second challenge was to secure reliable and stable wireless communication between each bunker location and its respective mover. The mover needs to be controlled at every point along its track so it can move in either direction, stop, raise and lower the target. The tracks extend beyond the bunker from 300 to 500m, with various elevation changes and turns. Normally, a large antenna placed at each bunker and on each mover would solve any signal communication issues. However, the antennas at Fort Carson could not extend beyond the protective wall that guards each mover from the live ammunition.
Solution
Weidmüller's WI-MOD-E-300 2.4 GHz wireless modem was tested and selected for the application because of its ability to operate within the required temperature ranges, its broadcast power — 802.11b (Wi-Fi) compliant at 300 mW, and its flexibility. This modem can be configured as either an access point, bridge, client or router. Weidmüller installed 10 of the wireless modems at five bunker-mover locations, using antenna and connecting cables that were already onsite from a previous vendor. Signal strength was improved to an operational level on four of the five ranges.
After several months, the customer determined that communications were not as consistent as desired. Weidmüller performed extensive signal strength site surveys at each of the 14 different bunker-mover locations to diagnose the problems. Results showed that the previously installed cables and antennas were at fault. They had not been properly installed by the previous vendor, and in some cases were incorrect for the application.
Weidmüller designed a solution to correct the communication issues at each range location, and streamlined the support and spare parts management for the Fort Carson range. All the components and equipment used for each bunker-mover location are identical and include:
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2.4 GHz, 300 mW Wireless Ethernet modem (bunker and mover)
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55FT jumper cable (bunker)
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2.4 GHz, 4DB OMNI antenna (bunker and mover)
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3FT jumper cable (mover)
Outcome
Weidmüller and Meggitt Training Systems have replaced all of the original faulty modems from a previous vendor, and installed all new connecting cables and Omni antennas in each bunker and on each mover. The entire range is up and fully operational, providing solid data and control connections for each of the bunker-mover locations. MTSI considers its Fort Carson digital range installation a complete success, and the U.S. military is actively using the range as a testing facility for tanks and other armor vehicles.
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Wireless Communications at Home on the (Firing) Range
