A Utahn's invention may someday help America's bombers hit desired targets or make it easier to receive jammed radio signals.
Dan Weber, whose corporation is based in Perry, Box Elder County, came up with a device that conceivably could revolutionize the science of outfoxing jamming signals. That could mean better guidance for smart bombs or being able to receive radio messages through the noise of deliberate interference.
The device, which Weber calls a comparative receiver, exists so far only in a small prototype that he built in his garage. Meanwhile, Michael Tompkins, assistant professor at Utah State University, Logan, has been evaluating its potential through a mathematical and theoretical description of the circuits.
What's it good for? In warfare, some munitions are guided to their targets using the Global Positioning System. The bomb adjusts its flight by using GPS satellite signals, picked up by a guidance kit attached to the bomb.
"The problem is, if you have even one really powerful jammer in your field of view, that guidance system could be basically rendered useless," Tompkins said. The bomb might cost $20,000 and the guidance system another $20,000.
Existing technology can be used to suppress jamming. Antennas that sort out jamming from desired signals use complex processing and expensive hardware, Tompkins said. "What we're doing is using a new technique."
If current technology is used to suppress the enemy jamming, the cost of a bomb might go up by $1 million.
But Weber's device probably would not add a great deal to a bomb's price. Theoretically, if a single jammer attempts to interfere with the GPS guidance, "we can still perform a mission," Tompkins said.
From what he's seen so far, he added, "it's an important breakthrough. But the simplicity of the hardware is fantastic."
Weber, whose company is Weber Technology Inc., said his notion about reading signals through interference involves analyzing the phase of the jamming. "We are selecting a period of time when a jammer has a minimum amount of energy, and then we are sampling the signals that are hidden behind it," he said.
The device could "see through the jamming," he added. And it uses "simple and inexpensive electronics."
What if two jamming sources are interfering with the signal? "Right now, our first research paper has been with one jammer," Weber said. "We're doing research for a second paper to deal with that situation."
Tompkins said that if a source of interference is arriving from the same angle as the signal one wants to pick up, "we're pretty much out of luck." On the other hand, the technology used today, adaptive antennas, also has the same problem.
"There are other signal processing tricks you can use to extract the desired signal in some situations, but our work does not deal with those," he added.
If multiple interferers overlap each other, coming from angles that are different from that of the desired signal, the device might be able to deal with them. Possibly, Tompkins said, "we can treat the composite undesired signal like one big old interferer and do a decent job of reducing their effects."
The device often may be able to suppress interference by a large margin, so the strength of the jamming signal is much reduced.
A provisional patent, protecting inventor rights while the device is further developed, was approved last summer, Weber said.
He outlined the lengthy process he went through trying to interest the Defense Department in the receiver. At one point he was encouraged to submit a proposal, but then it was not funded. After he was turned down again, he approached USU.
Once the device is proven effective, Weber hopes, the government may take another look. "We would like to start licensing out to Defense Department contractors," he said.
Tompkins modified Weber's circuits slightly, in his investigations. And he has submitted a paper on their operation to a scientific journal.
The device can "very effectively suppress a single interfering signal," he said. Meanwhile, he is evaluating the situation where multiple interferers come from various directions.
During combat, the Air Force should be able to take out jammers fairly quickly, so the likelihood is small that several would be operating at the same time. But one jamming broadcast turning on just as a bombing operation starts isn't as unlikely.
Eliminating the signals from one interfering source could be a great advance, when done with hardware that is much less expensive than current technology allows.
"There's a very, very marketable niche there," Tompkins added in an e-mail note. "That is, as long as we remain cheaper than adaptive arrays! There is little benefit if the same performance is achieved at the same cost."The device, Tompkins added, "definitely looks promising."
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