Companies are testing and rolling out new systems to counter the threat, either by overcoming jamming signals or by identifying and locating their source, they say.
In a speech at the annual Air Force Association conference on Sept. 17, Gen. William Shelton, commander of Air Force Space Command, which operates the 30-plus satellite GPS constellation, highlighted jamming as an increasingly common problem.
“Lots of jammers [are] out there for GPS,” Shelton said. “In fact, you can buy a jammer on the Internet. By the way, that’s illegal, but you can find them on the Internet and lots of adversaries around the world have GPS jamming capability so we’re going to have to learn to fight through GPS jamming.”
Lockheed Martin Space Systems of Denver, prime contractor for the next-generation GPS 3 satellite system, has said that the new satellites will have eight times the jamming resistance of their predecessors. The GPS 3 satellites are slated to begin launching in 2015 but it will be several more years before that system is fully deployed.
In the interim, companies are seeing growing demand for systems that counter jamming threats to both military and civil GPS signals.
“We've seen enough of it [that] we think there’s a market,” said Kevin Farrell, general manager of positioning, navigation and timing at Exelis Geospatial Systems of Rochester, N.Y.
A fairly common Chinese made GPS jamming device that can be found on the Internet. Purchasing or operating one in the USA is illegal. In the EU using one is illegal, but they can still be purchased.
Exelis has been testing a product called the Signal Sentry 1000 that detects and locates GPS interference sources and allows users to notify law enforcement.
As an example of the proliferation of commercially available GPS jamming devices and the problems they pose, Exelis officials have regularly cited so-called personal privacy GPS jammers, which are commonly used by truckers so employers will not know where they are. If enough trucks equipped with these devices were parked at an active shipping port, they could wreak havoc on signals used by maritime traffic.
Exelis officials said interest in the Signal Sentry 1000 has been particularly strong among airports and law enforcement agencies. The company is in active discussion on two possible sales of the system, they say.
Joe Rolli, Exelis’ program manager for Signal Sentry, said the technology used in the program could eventually lead to military applications.
Raytheon Co. of Waltham, Mass., is also working on a new product for its GPS anti-jam line called MiniGAS. Executives are touting it as the company’s lightest and smallest GPS anti-jamming system that helps overcome interference. On Sept. 11, the company announced its first contract for demonstrator units of the new system but did not name the customer.
The Defense Department, meanwhile, has been working on improved antenna solutions that would withstand jamming. In July, the Navy conducted a test in which it mounted a small antenna system on a unmanned aerial vehicle and subjected it to heavy interference. While there was no formal report on the outcome, Mark Burroughs, navigation lead for the communication and GPS navigation program office at Naval Air Station Patuxent River, Md., described the results as “very good.”
While many anti-jam units are about the size of a Frisbee, this system was about the size of a hockey puck, Burroughs said. The smaller size would allow the Defense Department to add another layer of protection, particularly on smaller vehicles.
The Navy plans to evaluate a series of anti-jam options, Burroughs said.
Experts and industry officials said one of the problems facing the military is accurately attributing the jamming to an adversary. While new technology may be able to pinpoint exactly where jamming is coming from, it creates questions about whether individuals or groups are acting alone or on behalf of an adversary.
This can be an important distinction given what Shelton had to say about options for countering GPS jamming threats.
“Certainly tactics, techniques and procedures can help. Antenna designs will help as well,” he said. “But let me tell you also that big jammers are called targets. As they radiate and perform their operations, we can identify, geolocate and destroy those targets in a campaign.”