C_AR
Taking The Search Out of CSAR.
Combat search and rescue (CSAR) is the art, and increasingly the science of rescuing personnel from hostile territory. Downed pilots and special operators are the classic users, but anyone equipped with the right radio to connect to the Joint Personnel Recovery Agency’s global communications network, can draw upon its assets.
To do this, DoD is fielding increasingly capable equipment to ensure that almost from the moment the user switches on the radio, rescuers will know precisely where to go, the health and status of their target, the nature of environment they will enter. This is being achieved by the introduction of a two-way communications capability using Milsatcom and direct communication throughout the recovery.
CSEL GROWS IN STATURE
Boeing kicked off development of the Combat Survivor Evader Locator (CSEL), after winning the Air Force-led contract to develop the next generation CSAR system for all DoD users in 1996.
CSEL shifts the paradigm of joint personnel recovery according to Mike Bates, program manager for CSEL at Boeing. “The big difference is the searching. Before CSEL, the military had to send aircraft out to try and locate the downed pilot and get within line of sight before picking up the signal. With CSEL, once a downed pilot pushes a button on his (AN/PRQ-7) handheld radio (HHR), within a couple of minutes the rescue center knows who they are, whether or not they are hurt and exactly where they are, anywhere in the world. From the mindset of the downed pilot, he gets immediate feedback. That’s a huge psychological benefit versus standing there scared, potentially hurt, bleeding and in shock, while not even knowing for sure that anyone knows that he is down. The rescue center now is immediately able to respond to the survivor using over the horizon (OTH) satcom, allowing the downed pilot to fully concentrate on his evasion and survival tactics. The rescue center, having his exact location (utilizing the latest SAASM GPS module), can start coordinating the rescue mission immediately.” All communications are secured using NSA-approved cryptology.
“The CSEL network design is key to this new capability”, Mike Alexander, CSEL lead systems engineer explained. “What is novel about the system is that it is totally integrated into the government network infrastructure. This gets the survivor’s message directly to the right rescue center.” Once the downed pilot or other user “lights up” the handheld radio, the information that he is down and needs help is routed using the OTH UHF satcom network to one of four bases stations worldwide, one each in Virginia and Hawaii and two in Italy. Then, using SIPRnet and other government networks, the message is sent to the designated rescue center where twoway communication then proceeds. Today CSEL relies on UHF Follow On and other government UHF assets and in the future that will include the Mobile User Objective System (MUOS).
THOUSANDS IN SERVICE
CSEL is now being used operationally in Afghanistan and Iraq with the Army and Marine Corps in fixed and rotary wing aviation and on board some Navy carriers as well as USSOCOM. The system has already been successfully used, Bates explained, “For the reason for which they were designed, however the details are classified at this point.” He added that the Air Force will join the other services later this year in fielding CSEL on their fast jets as well as C-130s and C-17s, once training with the new radio is complete.
“Demand is strong and the services are solidly behind the program,” affirmed Bates. Boeing has already sold 16,000 radios with 12,000 delivered and further sales of 15,000-20,000 units expected over the next three to four years, against a DoD requirement for in excess of 40,000 radios. Several NATO users have also been asking for CSEL since 2006. The Air Force is currently processing the FMS cases through DoD and he expects to be selling CSEL internationally by the end of the year.
UPGRADES
Boeing is now embarked upon two parallel DoD funded upgrades that address improvement to CSEL’s software and hardware. Under the Block 1B systems upgrade, Boeing is working with the NSA and the DoD to enhance network security and information assurance features in line with the overall DoD security architecture such as enhanced firewalls, intrusion detection and advanced e-mail screening.
A second feature of Block 1B is the upgrade from the current Unix-based CSEL workstation to a Web-based capability. This allows any user with access to a Web browser and connectivity to the SIPRNET to access the CSEL Website and support time-critical CSAR missions.
Bates added, “Today, when the government wants to add another rescue center location, it could literally take 30-60 days to establish it, because we have to procure the hardware and software and then install it. Under the Block 1B Webbased architecture we could now have someone come up as a JPR center supporter within minutes.”
CSEL’s Block 2 upgrade provides terminal area features with changes to both the radio and the rescue aircraft under two strands; terminal area communications (TAC) and terminal area guidance (TAG).
Currently, rescue aircraft are able to receive CSEL radio messaging updates via the Integrated Broadcast Service. Alexander explained, “If the rescue aircraft is hooked up with a MATT receiver, they can receive the encrypted secure one-way messages (including GPS position) transmitted from downed pilots, any time the CSEL radio is transmitting.”
TAC provides a series of improvements to the ingress phase of the rescue by enabling lineof- sight secure two-way messaging during the last 50 miles of pickup. Alexander continues “They can communicate back and forth with the downed pilot as they are flying inbound, sending secure text, GPSbased position information and status.”
TAG is the last part of Block 2, and adds direction measuring equipment (DME) capability to the CSEL radio as a hardware upgrade. Using DME, the rescuers onboard PLS radio is able to calculate the distance and direction to the AN/PRQ-7 based upon the timings of the return signal. With multiple “pings,” improved accuracy is possible. This upgrade is 100 percent compatible with the existing installed CSAR DME equipment.
This prompts the question: Why add DME now? Alexander explained that when the CSEL requirements were developed it was the first time users were going to have true SAASM GPS capability back to the rescue center. The DME waveform, which dates from the late 1970s, was useful but nonetheless was not particularly accurate or secure and so it was decided it was no longer a desired capability.
Alexander continued, “[DME] did however, have the advantage of a large installed base of aircraft with that built-in capability. Since that time, the users, and especially the Air Force have decided that they want that legacy feature because it provides a non-GPS based secondary option if GPS is denied.”
The Block 2 upgrade also requires some changes to the CSAR aircraft’s equipment. Boeing is currently developing a new electronics module for the new TAC waveform in both the Cubic ARS-6 v12 and ACI’s ARS-6 Army guidance systems, designed to bring the rescue helicopter to the pilot’s position. The module is now undergoing qualification testing and will now be integrated into units over the next six months.
Bates concluded, “Size and weight mean a lot, so it is very important that the radio doesn’t weigh any more than it has to and still able to accomplish its goals. What the government didn’t want to do was to have this be the radio of all radios. It needs to serve its purpose, to be small and very robust. This is by far the most tested radio ever built and satisfies the exact need that the users built it for.”
HOOK
For many years the mainstay of U.S., NATO and coalition search-and-rescue and comprehensively tested in a number of conflicts is the General Dynamics AN/PRC- 112. Arne Olson, director international business for General Dynamics C4 Systems’ Assured Communications, reports that sales of the radio remain strong. It continues to be on the GSA Schedule and is in service with 23 nations with some 19,000 in service today. “Basically,” Olson concluded, “We are present everywhere, throughout the services.”
From a simple handheld DME-based beacon, the AN/PRC-112 has evolved over many iterations, the latest version being the AN/PRC-112G, part of the Hook2 CSAR system that also includes interrogation systems. This radio incorporates many features such as OTH UHF MILSATCOM messaging, GPS and the addition of the new 406 SARSAT peacetime SAR beacon.
Olson explained that the system is likely to stay as the “G model.” As a software-defined radio, improvements can be incrementally added simply through new software. “We have added the SATCOM OTH messaging, GPS interference detection and the 406 beacon which weren’t on the original G model. These improvements simply register on the front display as an additional software or waveform that is in the radio.”
A feature popular amongst users since its release in April 2005 is the situation report, which consists of 15 fixed questions covering the local environment, health and other basic status indicators. Previously the user answered these individually, sending out 15 separate messages; now they are responded to collectively and sent in a single databurst, reducing susceptibility to detection.
Olson said, “Those items have been very well received from the user community and [the users] are appreciative that [the items] were pushed out in software releases at no cost.”
Olson describes the software improvement process as analogous to Windows updates. “It’s just like your computer. From time to time [we] do software releases and in some of those releases we do add additional capabilities and make a decision to charge for them or not. In the case of Situation Reports software, they were significant in terms of adding capability but small in terms of software changes, so we went ahead and put them in at no cost. Features like additional waveforms, 406 and SATCOM have license fees, so we do charge additionally for those.”
There are no significant enhancements being planned for the “G” over the next 12 months. Effort is, however, going into other capabilities and a radical downsize potentially linked to the companies work on JTRS HMS and its role on the MUOS UHF SATCOM program.
One of those new capabilities is adding Blue Force Tracking (BFT) to the G under the Joint Personnel Recovery Systems program demonstrated as part of a joint program between the U.S. and U.K. This would place an L-band BFT board within the G. Olsen explained that the proof of concept had been achieved as was being examined by the parties involved as to how to take this forward.
Using commercial GPS, the G updates its location once per second. “We have never used SAASM because of the battery drain,” explained Olson. “We don’t feel that it is a requirement for CSAR. That’s not a universally held view but it is a view held on this program.” The interference detection software on the updated AN/PRC-112G provides added protection. In addition, the DME waveform, onboard the 112 family from the very beginning, provides a terrestrial backup and simultaneous complement during the terminal phase of recovery.
General Dynamics has assiduously developed a user community around the HOOK2 system. The latest three-day users’ conference was held in April at the company’s Scottsdale facility with delegates from eight European and Pacific nations.
Olson said, “We have lot of open question and discussion about the product, and from that we get feedback. If we get enough feedback on adding a capability, we take a serious look at adding it to the radio.” He cited the situation report multi-messaging as one new feature that came directly from the user group at earlier events.
PRC-434G/SV
Another small radio suited for CSAR is the Tadiran Spectralink PRC-434G/SV personal survival radio (PSR). In a small package, the radio is designed for onehanded use, has large LCD screen and an embedded GPS receiver. The battery can provide 30 hours with a transmit-to-receive ratio of 1:10 and more than 96 hours in sleep mode. The PSR can be programmed for automatic activation under certain conditions or it can be activated manually. To reduce detection likelihood, the device has 40 canned messages that can be sent in a single short burst or, in the same burst fashion, standard coordinates can be transmitted.
SAR
Take out the combat, and SAR changes radically from discrete and stealthy recovery to an all points bulletin that can be received by all peacetime agencies. This has been provided by a Cold War-era satellite international constellation that was used by SAR beacons such as the AN/PRC-90 and AN/URT-33. The analog transmissions made by these and similar beacons will cease to be detected by the satellite network in February 2009 when a new digital signal on 406 MHz will take over. All old SAR beacons will cease to be detected; so users must have new 406 beacons in place by then to retain over the horizon alerting.
The Navy has already made its selection opting for the Tadiran AN/PRC-149 personal locator beacon and voice transceiver (PLBVT) to replace the PRC-90 and AN/URT-140 to replace the AN/URT-33. The AN/URT-140 emergency locator transmitter (ELT) is embedded in the personal survival pack on the ejection seat and begins transmitting immediately upon ejection. The AN/PRC- 149 is carried in the pilot’s flight suit and provides a GPS geo-location and VHF/UHF capability. Under the Navy program Tadiran Spectralink has also supplied several hundred Swimmer Remote Control Units, designed for Navy rescue swimmers.
The Air Force is currently in the midst of its 406 program currently named URT-XX. Two parallel SBIR development contracts were awarded in 2006, the first to Digital Angel Corporation (DAC), which is working closely with its U.K.-based subsidiary Signature Industries and the second to a team of Signal Engineering and Tadiran Spectralink.
Brian Clayton, DAC’s project director for URT-XX commented, “The critical requirement from the USAF was for the URT-33 replacement to be a form and fit replacement for the URT-33 whilst stepping up the performance to also provide 406 MHz plus commercial GPS. This technology did not exist at the time USAF placed the contract, but we were already working on a miniaturized set of electronics based on an existing design. With a small amount of additional development work we have been able to reduce the footprint of the board set to approximately a quarter of the size of what was available.” Speed of beacon operation is also important to the USAF requirement, which calls for rapid GPS fix acquisition and a successful SATCOM transmission within seconds of activation. This ambitious performance requirement is to ensure that an airman who has ejected can be identified and located while still under canopy.
The Air Force is on the fast track to get the equipment completed and deployed by February 2009, with roughly 15,000 required. Clayton explained that DAC would deliver their completed product in July with flight tests and trials process expected to be concluded by November.
The Air Force has not yet finalized their PRC-90 replacement program but the SAR stalwart’s availability has prompted them to look at interim solutions. Clayton explained that at a recent USAF conference attended by the safety chiefs for each of the major commands of the Air Force, the Signature Industries SARBE 6-406 beacon was presented as a potential solution. The USAF has also evaluated and is continuing to evaluate the Signature Industries G2R product, which also has a CSAR capability. The company has also provided customized solutions for U.K. special forces and others.
CONCLUSION
CSAR and its benign compatriot SAR, are designed to deliver a common goal: the safe return of isolated personnel, using communications that give precise coordinates and voice and data updates that get to and only to the people that need them. In technology terms that is not difficult, but where the complexity arises is in ensuring that this capability is sufficiently rugged, compact and with intuitive interface to ensure that the link with rescue and recovery can be carried and operated by lone and often injured personnel, very far from Kansas. ♦