September 2005 
Volume 04, Issue 5 
Tech Talk

Successful rescue mission

By Jerry Drelling

With the Combat Survivor Evader Locator (CSEL) radio, downed pilots and members of special operations forces trapped behind enemy lines will be counting minutes and hours—not days—before rescue.

With the CSEL system, which uses satellites and precise Global Positioning System (GPS) technology, rescue teams will know exactly where isolated personnel are at all times.

"We like to say that CSEL takes the search out of search and rescue, because you just go rescue the person. You don't have to go search for them," said Alex Lopez, Boeing's director of the Anaheim, Calif.–based Network Communication Systems, where CSEL was developed.

In March, the U.S. Air Force awarded Boeing a $43.6 million full-rate production contract for the system. The acquisition of as many as 46,000 radios by the Air Force, Army and Navy could push the total value of the contract to $250 million.

Designed for easy use, the multifunction CSEL radio is economical technology that gives U.S. forces a tactical advantage. Unique communication and message encryption techniques prevent signals from being intercepted or decoded. CSEL will enable rescue forces to authenticate and communicate with isolated personnel in near real time, anywhere in the world.

The genesis of CSEL was in 1995, when U.S. Air Force Captain Scott O'Grady was shot down over western Bosnia. O'Grady spent six days evading Serbian troops and living off the land. To the Air Force, that his rescue took six days was a sign the search-and-rescue process needed changing.

Key to CSEL capability is the use of satellites. The military's Ultra–High Frequency Satellite Communications network provides the capability for two-way messaging between the "evader" and the joint search and rescue center. Because the radios use existing systems, no new satellites had to be launched to meet the global coverage requirement.

Statistics indicate that downed pilots' chances of survival diminish rapidly once they've been on the ground more than 30 minutes. Legacy survival radios such as the one carried by O'Grady depend on line-of-sight technology. If a rescue plane or helicopter isn't overhead, or if a mountain is in the way, older survival radios won't work. Although legacy radios are equipped with GPS, short battery life means they must be used sparingly. CSEL's batteries will last up to 21 days.

"With the legacy system, the rescue team received a homing signal. By careful piloting of the search aircraft, you were able to gain a course bearing on where the survivor was located," Lopez said. "The accuracy of this locating method improved as the rescue aircraft got closer to the survivor. However, the extensive search exposed both the rescue party and the survivor to unnecessary danger."

CSEL has changed that. And for U.S. warfighters, it's a lifesaving difference.

This article first appeared in All Systems Go, a journal of Boeing Integrated Defense Systems.

How it works

A pilot ejects over hostile territory. Landing and taking cover, the pilot pulls a 2-pound radio from his or her flight vest, turns it on and hits the "immediate" button. The radio, a Combat Survivor Evader Locator, instantly alerts rescue forces simply that the pilot is down. It uses encrypted low-probability-of-detection waveforms (signals hard to detect by normal enemy frequency scanners) to send the message—and sends it directly to the specific joint search and rescue center responsible for rescue operations in the area, saving critical time.

While rescue-planning personnel retrieve the survivor's information from a computer database, the radio uses military-grade Global Positioning System navigation capabilities to acquire a GPS fix. It then sends a second message including this precise location information—and detailed rescue-mission planning begins.

Within minutes the rescue center replies, giving specific instructions to reach an optimal rescue location, including optional GPS waypoints, which load directly into the radio's memory. The downed pilot can use these waypoints and the CSEL's integral GPS to navigate to the planned rescue landing area. The survivor and rescue center also can transmit and read back-and-forth text messages, monitoring survivor health status and communicating updated GPS fixes, until the rescue forces arrive.



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