It’s encouraging to see how fast the electronics that support signal intelligence (SIGINT) are progressing. Field-programmable gate arrays (FPGAs) are playing an increasing role.
“Digital signal processors (DSPs) and general-purpose processors have an established group of manufacturers, tools, languages, applications and libraries of code, whereas if you want to start using FPGAs there is a significant advantage in terms of power consumption and being a better overall device,” explains Craig Sanderson, product manager with Nallatech in Glasgow, Scotland.
Sanderson warns, however, that from the user perspective it is less easy, at least initially. “The arrival of dual- and multicore processors is ushering in a sea change because their software is complex,” Sanderson says. “Between generations of DSP and general processors there might be changes in architecture, which means you can’t just put the application straight on. FPGA manufacturers tend to give you what you had before, but more of it.”
Progress in SIGINT is great news because its purpose is to head the enemy off at the pass, knowing what the enemy is going to do before he does it, and keeping soldiers, sailors, and aircrew-and their equipment-as safe as possible as part of the electronic warfare approach.
Clearly there is still some way to go, says Angsuman Rudra, product manager with Interactive Circuits and Systems (ICS) in Ottawa. “One of the big challenges now is how to deal with improvised explosive devices (IEDs). They are typically detonated by something like an ordinary electronic garage door opener. Jamming the low-power, low-volume signal would prevent the device detonating, but trying to locate that signal among a lot of noise is difficult and usually it’s too late.”
Here, too, there is good news. “The solution is coming with better analog to digital (A-D) converters-12, 14, and soon 16 bit-that will be able to detect those lower-power signals. Everything is possible with enough money and engineering resources. We’ve not yet got systems that can monitor gigahertz of spectrum instantly, but you can slice it up into hundreds of narrow bands to raise the frequency of the scans and avoid missing the crucial signals.”
It’s the changing nature of the battle that is causing most concern. The Madrid train bombings in March 2004 (which killed 191 people and injured 2050) and the London bombings in July 2005 (which killed 52 and injured 700 more) made clear that civilian populations in Europe are targets, and it is very hard to protect them, although SIGINT and their countermeasures are used all the time and are constantly being stepped up.
For example, Honeywell Aerospace has just developed a secure version of the Aircraft Communications Addressing and Reporting Ground System (ACARS) datalink, and has demonstrated it to the U.S. Technical Support Working Group (TSWG). The TSWG coordinates governmental interagency and international research and development for combating terrorism and protecting critical infrastructure systems.
“The ACARS system originated in the 1970s to provide a very basic way of the crew communicating with those on the ground,” explains Don Kauffman, technical manager at Honeywell Aerospace Advance Technologies in Phoenix. “Since then its use has expanded dramatically, so we even have ACARS coverage over the oceans through the use of satellite.
ACARS, he says, is “character-based and therefore readable. In Europe a number of airlines’ communications were intercepted and details published in a newspaper, and there have been instances of phantom air traffic controllers giving false instructions. There are hobbyists who like to listen in, and anyone can Google to get ACARS information-buy a scanner from their local store for 50 Euros and then you have a map of where planes are and where they are going. Clearly, someone with ill intent could make use of it and build up a lot of information over time, particularly as U.S. Air Force adopted ACARS about five years ago for larger aircraft.”
Honeywell has added user authentication and integrity of the message, as well as encrypted the contents, Kauffman adds. “We can also include a digital signature to prove where the message originated and verify that the message is exactly as it was sent without a ‘man in the middle.’ It was all done using international standards for cryptography that are proven. Now it will be extremely difficult to attack using this protected ACARS. We feel we’ve closed this door and very tightly.”
The implication is, though, that there are still any number of other doors to try-and they’re not all necessarily technological weak spots. Indeed avoiding use of electronic technology is creating huge problems, as demonstrated this summer by Hezbollah in Lebanon. The well-equipped Israeli armed forces had far superior numbers and tried to destroy the much smaller, not so well-armed Hezbollah. It failed.
As one analyst commented wryly, “It’s very hard to pick up give-away electronic transmissions-even with enormous listening posts such as the Israelis have-when the means of communication is through notes passed from hand to hand or land lines are used unpredictably. In the defense community, it is widely believed that Osama Bin Laden is still at large because he realized that equipment like satellite phones could give him away and stopped using them.”
That and the use of so-called cut-offs-these are messengers who carry the notes with knowing neither from whom they came, who its ultimate recipients will be, nor their purpose. This means that even if the cut-offs are captured and interrogated, they cannot reveal what they don’t know.
Indeed the only way to counter this low-tech approach is by good, old-fashioned human intelligence-paid informers and spies-which are hellishly difficult to recruit and manage among closely knit groups. Nevertheless, the more we recognize that first-hand, human intelligence is needed to complement that obtained electronically, and do something about it, the better chance we have of soldiers surviving IEDs and civilians surviving their train journeys to work.
Chief Editor, Military & Aerospace Electronics Europe