High tech aids search for answers
- By Bob Brewin, John Monroe
- Jul 28, 1996
When TWA Flight 800 plunged into the ocean just 15 minutes out of John F. Kennedy International Airport, the USCGC Juniper, the first of a new generation of high-tech Coast Guard cutters, took up a position at the crash site and coordinated the early stages of the search-and-recovery effort.
Since those first few hours, the multiple-agency flotilla working the scene has used leading-edge technology in nearly every aspect of the mission - from software that plots out search missions and satellite-based Global Positioning System technology that guides the ships to radar that helps identify and map out the wreckage and software that sorts out evidence.
The Juniper, commissioned just two weeks earlier, is a blueprint for future Coast Guard cutters, said Ensign Chris Murray, one of the ship's officers. "We have performed incredibly well," Murray said. The new high-tech vessel "has really proven itself, and we will continue to move in this direction in leaps and bounds."
The Juniper uses a GPS receiver as part of a shipboard fiber-optic local-area network. The LAN runs two key PC-based software packages: the Electronic Charting System, a computerized nautical chart developed by Offshore Systems Ltd.; and the Dynamic Routing System, a navigation software package created by Nautronix.
By combining these programs with the positioning information, "our ship has the capability to drive itself," Murray said.
When the Coast Guard arrived on the scene, the crew held position at the site of the crash, laid out a search grid on the electronic chart and directed the 30-plus government and volunteer civilian vessels that began a full-scale search effort for wreckage and survivors. "We could track them because our radar system can overlay directly on the [electronic] chart," Murray said.
The computer system enabled the Juniper to hold in place automatically by monitoring the GPS information and engaging thrusters or propellers to prevent drifting with wind or water. When the Juniper took part in later missions, the crew could run on automatic pilot with precision by laying out a course on the electronic chart and then feeding it into the Dynamic Routing System.
The Juniper tapped into the Coast Guard's Differential GPS system (DGPS) which fine-tuned the signal provided by the DGPS constellation, using signals from the nearby Montauk Point DGPS transmitter.
David Pietraszewski, the senior scientist at the Coast Guard Research and Development Center in New London, Conn., said the Montauk Point DGPS station provided the Juniper with positioning signals with an accuracy of about 2 meters.
DGPS helped Coast Guard, Navy and National Oceanographic and Atmospheric Administration vessels as they swept the sea looking for chunks of fuselage and the "black box" flight data recorders that might provide clues to the cause of the accident.
GPA Served as 'Key Element'
Capt. Raymond Scott McCord, the Navy's supervisor of salvage who directed the search-and-recovery effort for the sunken TWA debris, said GPS was essential to the effort. Gary Kozak, the regional sales manager for Klein Associates, which manufactured the sonar the Navy used to find the debris, also called GPS a "key element" of the effort.
"The sonar provides the imagery, and the GPS signal tells you exactly where it was made," Kozak said (see story, page 28). This combination of sonar images and highly accurate positioning information allowed the Navy and NOAA to generate detailed digital charts of the ocean bottom, pinpointing the location of debris in three widely scattered fields each day.
The search patterns themselves were generated by computer technology at the Coast Guard Command Center in Boston when it began overseeing formal recovery efforts.
A PC-based program called the Geographic Display Operations Computer allowed the staff to plot detailed patterns that left no area uncovered and then print out the information and fax it to the vessels.
"What would take two to four hours using [paper] charts and manual forms, I can now do in 15 minutes on the computer," said Lt. Charles Fosse, a command center controller. "We are able to send assets to the scene in much less time with [more] accurate information."