Taking the Search Out of Search and Rescue
Written by Peter Buxbaum
CGF 2011 Volume: 3 Issue: 3 (July)
Can technology take the “search” out of “search and rescue”? That is the premise behind several sophisticated technologies deployed by the Coast Guard and the commercial and recreational vessel operators it protects. Seeing as it is heavy weather that often brings on the distress necessitating search and rescue, Coast Guard search and rescue units rarely operate in fair weather. Rough sea conditions, high winds and driving rains create a harsh environment that renders a visual search of the waters extremely difficult, making the intersection of training and technology critical for success.
SAR Planning and Coordination
Search and rescue has long been one of the Coast Guard’s core missions. As such, the Coast Guard has an extensive SAR organization, beginning at headquarters where policies are promulgated and standards articulated, to the SAR units located in each Coast Guard district where personnel are trained, equipment procured, and of course, the actual search and rescue operations are performed.
The Office of Search and Rescue at Coast Guard headquarters in Washington “is responsible for the functioning of the overall system, to see to it that training is available, and that there are appropriate policies in place,” noted Commander Max Moser, chief of SAR policy at Coast Guard headquarters. In his position, Moser is in charge of setting policies such as defining what constitutes a SAR case, delineating the requirements for conducting SAR operations, regulating how units are to respond to SAR situations, and determining what resources will be allocated to them. “For example,” Moser explained, “if a notification comes in of a red flare, that is considered by policy to be signal for distress and requires a response.”
The search and rescue apparatus below headquarters consists of several levels. SAR coordinators are found within the Atlantic and Pacific commands as well as within each Coast Guard district. “The SAR coordinators make sure that there are resources on hand to conduct search and rescue operations and that the missions are completed properly,” said Moser. Below the SAR coordinators are the mission controllers. “They are responsible for opening a SAR case every time a distress signal comes in,” said Moser. “The mission controllers are also responsible for the search and rescue units” that perform the actual operations. It is the SAR planners who allocate resources for the execution of individual missions. However, although there is an established SAR organization, Moser emphasized that “each SAR case is different. There is no typical case.”
Optimizing the Search
SAR personnel get specialized training and must keep up their qualifications, Moser noted. Training includes operation of small boats, particularly in heavy weather, lifting of victims out of the water, and when and how to de-water vessels. SAR training takes place at the National SAR School where SAR planners and mission controllers are trained in, among other things, the use of the computerized Search and Rescue Optimization Planning system, or SAROP.
“Planners are all put through school where they are taught how to use the program, how to input environmental data, how to develop search and rescue scenarios, and how to indicate the SAR resources available,” said Moser. “The system produces a SAR action plan. The system also keeps track of areas that have been gone over and provides searchers with optimal search areas and patterns to be used in each SAR case.”
SAROP, which was developed by the Coast Guard, first came online in 2007. The technology is based on a Monte Carlo optimizer—a class of computational algorithms—which takes environmental data from databases of the National Oceanic and Atmospheric Administration (NOAA) and elsewhere—such as Coast Guard buoys that provide data on environmental conditions—and information provided from different meteorological sources imported into the system.
The SAROP data, in turn, is incorporated into the Common Avionics Architecture System (CAAS) provided to Coast Guard aircraft by Rockwell Collins. “CAAS is a flight management system that includes all of the search patterns generated by SAROP,” said Robert Koelling, the company’s principal program manager. “The processing unit and cockpit displays are onboard the aircraft. The system also has built-in search pattern capabilities that the Coast Guard can set up on the ground or in the air. It can manage numerous types of search patterns and supports all the functionality that optimizes the search pattern in order to find people in trouble quicker.”
Locating Beacons
CAAS also communicates with the DF-430 direction finder. The DF-430, also provided to the Coast Guard by Rockwell Collins, was introduced in 2007 and has been installed on all Coast Guard aircraft and integrated with their flight management systems. The DF-430 enables aircraft to receive and immediately locate activated emergency position indicating radio beacon (EPIRB) signals, allowing Coast Guard crews to go directly to people in distress.
EPIRBs and PLBs (personal locator beacons) are 406 MHz devices which transmit signals on internationally recognized distress frequencies. All beacons must be registered with NOAA. NOAA monitors the 406 MHz signal and the Administration’s search and rescue satellite-aided tracking system (COSPASSARSAT) detects and locates distress signals and forwards the information directly to the Coast Guard. GPS coordinates also assist search and rescue crews.
“An EPIRB will emit its signals when an operator pushes it into the water or it floats free of the vessel,” said Moser. “The signal is picked up by satellites that fix its position and provide this information to the nearest SAR coordinator.” Airborne rescuers use the on-board DF-430 to hone in on the EPIRB signal. “Sometimes the satellite positioning is not as accurate as we would want,” said Moser. “The DF-430 is able to locate the EPIRB much quicker.”
“The DF-430 gives Coast Guard rescuers the ability to hone in on a signal from far greater distances than previously available, allowing them to pinpoint the location of distressed vessels from as far away as 200 nautical miles,” said Koelling. “Before the DF-430 was introduced, rescue aircraft had to be within a few miles of vessels before they could pick up the older standard distress signals. Less searching makes it possible to execute faster rescue missions.”
The DF-430 conveys critical information to Coast Guard personnel. For example, when a beacon begins transmitting, its location pops up on the cockpit flight display; the system also provides accurate lattitude and longitude of the beacon and captures its serial number so that it can be verified.
Rockwell Collins is working on a new product, the DF-500, which is currently in prototype form. This new system upgrades the capabilities of the DF-430; as more distress frequencies become available, the DF-500 will be able to pick up all of them. In addition, whereas the DF-430 is based on analog communications technologies, the DF-500 will be a fully digital product.
In addition to the EPIRB, which is required for larger vessels such as high-speed ferries and commercial fishing vessels, other beacons include the PLB, which can be handled by a single person and is used on smaller vessels, and the emergency locating transmitter (ELT), which is used on aircraft. “All of these transmit at 406 MHz and each send digital distress signals by satellite which provides the Coast Guard with an initial alert position,” said Chris Wahler, a product line manager at Cobham Commercial systems, a beacon manufacturer and the sole maker of EPIRBs in the United States. Multiple agencies, including the Coast Guard, the Federal Communications Commission and the Radio Technical Commission for Maritime Services (RTCM), an independent, nonprofit organization, have input into the technical and performance requirements for maritime beacons.
The EPIRB and PLB offer different capabilities. Both were designed for the maritime environment but the EPIRB must be able to float upright autonomously, be water activated, have the ability to transmit its distress signal for a minimum of 48 hours at temperatures as low as -20 degrees Celsius, and have a strobe light on board.
The PLB transmits the same kind of distress message as the EPIRB but must be activated manually, it may transmit for only 24 hours, and it may or may not include a strobe light. “The benefit of the PLB in a maritime situation,” said Wahler, “is that it is smaller and lighter and can be handled by an individual crewman. Boats carrying EPIRBS have one per boat and it is mounted in a bracket somewhere on the boat.”
The ELT, the aviation version of the 406 MHz beacon, must be crash activated, must work at defined altitudes if not in a pressurized cabin, and must withstand colder temperatures than the maritime beacons.
“The 406 MHz beacons take the search out of search and rescue,” said Wahler. When a vessel is reported overdue, “The Coast Guard will launch a rescue mission. It may spend some time broadcasting alerts to vessels in the suspected area. They may try to coordinate with other agencies and entities to find out if anyone heard a Mayday broadcast. If these efforts don’t bear fruit the Coast Guard may then go to a needle-in-thehaystack search based on information they do have.”
Conversely, when the Coast Guard receives a beacon message, it immediately knows a vessel is in distress, the location of the vessel, and the closest rescue assets to deploy to that location. “It not only removes the uncertainty of whether a distress situation exists,” said Wahler, “but provides a location of where this event is happening.”
The Coast Guard vessels themselves are also equipped with the 406 MHz beacons, Wahler noted. “Flight crews and rescue swimmers carry our PLB equipment when they go on a mission. This is not only a product for the general population but for the Coast Guard members themselves. The beacons allow the Coast Guard to spend less time on searching for survivors and more time executing the rescue.”
Thermal Imaging
According to the NOAA website, the COSPAS-SARSAT system is credited with rescuing nearly 300 people in the United States in 2010 and nearly 7,000 since 1982. In the first five months of 2011, 88 people were saved thanks to the use of 406 MHz beacons.
An emerging technology that aids in search and rescue missions by identifying persons and objects in the water is thermal imaging cameras. These cameras use infrared sensors to detect the heat signatures of individuals or objects being searched for, projecting a picture of the area on a screen. NVTS, which is currently proposing to equip smaller Coast Guard boats with its systems, manufactures a series of thermal imaging systems suitable for small boats, helicopters and larger vessels, with ranges of between two and 14 kilometers.
“Our technology is unique because it is modular,” said Joe Janson of NVTS. “You can remove and change payloads in the field for serving or upgrading without having to pull down the whole camera.”
NTVS’s infrared cameras have their temperature parameters set to aid in SAR detection. “The parameters are set to look for certain objects in water, whether human or debris,” said Janson. “Neither electronic chart plotters nor radar can provide this type of function.”
Dress for Success
Given the harsh marine environments in which SAR operations take place, it is critical that crews—commercial, recreational and Coast Guard alike—be outfitted in the proper gear. On the Coast Guard side, “Each of the crews is required to have a certain level of gear depending on weather conditions,” explained Moser. “Crews will always have jackets on. Many use inflatable types, especially on small boats. Crews operating in places like Alaska or the Northeast during the winter have much more gear such as dry suits, booties and gloves.”
Aerostar International Inc. supplied thousands of anti-exposure suits to the Coast Guard for years and still maintains and repairs those suits when needed. “The suits are for cold water immersion,” said Margaret Kearney, a company product manager. “Pilots, crew and rescue swimmers each wear a different design as determined by the Coast Guard.” For example, the swimmers’ suits are made more flexible than the others and include a stretch panel; suits for back-end crew members include more knee protection than the pilot suits because they suffer more abrasions during the course of their activities. The Coast Guard sends suits to Aerostar periodically when they need repair, such as when a pinhole appears in the suit which can cause a leak if the fabric tears, or when the neck seal needs to be reinforced.
Mustang Survival provides a variety of protective gear to the Coast Guard that includes flotation, anti-exposure and thermal management properties. “Coast Guard personnel wear certain gear based on the combination of air and water temperature,” explained Brian Dalgliesh, the company’s director of business development. When that figure is above 100, they will usually wear a float coat, which provides hypothermia protection and flotation in one. The float coat contains a specially formulated soft foam which provides both protection as well as flotation. Below 100, they will switch to a dry suit which is fabricated from military grade Gore-Tex, which is both waterproof and breathable, and a soft foam liner.
“We try to find ways to mitigate the thermal burden when personnel are not in the water,” said Dalgliesh. “We don’t want them to overheat while they are on the boat. There is a fine line between being warm enough while in the water and too warm out of the water. Coast Guard personnel have to be prepared to become victims themselves,” he added. “Cold water saps the body of heat three times faster than air.”
Proper protective gear is important from the rescuer standpoint, but also for those who may need to be rescued, Moser added. “That is the preventative side of SAR,” he said. “Boaters need to know about what type of gear to have on board to make it easier for the Coast Guard to find them and to make sure they can spend an extended period of time in the water so the Coast Guard has the time to find them.”
“The gear available to recreational vessels are important pieces of the SAR system,” noted Moser. “At least it gives them the opportunity to stay alive long enough for us to get out there and for them to provide notification to us that they are in distress.” ♦