We're Jamming: GPS Weakness Could Sink Wireless
A timing expert from the National Institute of Standards is concerned that the ease with which GPS signals can be jammed could spell trouble for wireless networks, as well as many other commercial endeavors, in the coming years.
Dr. Marc Weiss of the Time and Frequency division of the US National Institute of Standards and Technology (NIST) laid out his concerns at the recent Mobile Network Security Strategies conference in New York City. Weiss said that wireless networks increasingly require pinpoint accurate timing to synchronize transmissions between basestations and deliver faster connectivity, and they rely on global positioning system (GPS) signals from satellites to deliver that data.
"Most industries don't even know how dependent they are on GPS," Weiss told the crowd. "The problem is it's vulnerable -- the signals are extremely weak."
Weiss should know -- he's been working in this field for more than 30 years. (If you want to dig into the technical details of using a GPS signal to synchronize clocks to a standardized time, here's a paper he wrote on the topic in 1980.)
Weiss said it only takes a picowatt at the antenna to block GPS signals in the vicinity. "I've heard of garage door openers blocking GPS," he said.
This means that a number of unintentional and malicious jamming possibilities could drown out GPS and thereby affect transmissions over wireless networks.
Weiss cited the infamous example of a trucker who sped past Newark airport at the same time every week with a GPS jammer blazing -- to stop being tracked by his employers -- and shut down the navigation systems at the airfield.
And regular Light Reading readers will remember the major problems that LightSquared faced because its network signals were found to interfere with GPS. (See LightSquared: The Company That Won't Die.)
The issue is set to become an even greater concern as small cell basestations are added to the edge of mobile networks, and it was a topic of debate during the Q&A session at the end of Weiss's presentation. Several conference attendees asked whether the Precision Time Protocol (PTP) could be an alternative method of synchronizing radio access network infrastructure. (See Synching Up Small-Cell Backhaul.)
"The problem with PTP is you can only go a couple of hops and have it keep the timing," said Weiss. (It should be noted that some in the audience didn't appear to agree with that analysis.)
Weiss's real concern, however, is the prospect of malicious jamming from parties deploying much more powerful megawatt devices. North Korea has reportedly been attempting to use such transmitters to block the GPS on US spy planes since 2011.
The NIST guy's worry is that someone could smuggle a powerful jammer into a big city such as New York and blot out navigation channels and communications networks while remaining undetected. "The US lacks the capability to rapidly detect and geo-locate malicious GPS jamming."
As Weiss suggests, this has wider implications beyond the wireless industry. He also said that GPS spoofing has already been used to take down a "drone helicoper" by convincing it that down was up. (See Here Come the WiFi Drones.)
— Dan Jones, Mobile Editor, Light Reading