GPS satellite signals now play a crucial role in enabling you to call your mother, provide power to your home, and facilitate the landing of your aircraft; however, a cheap plastic device poses a risk of disrupting these important services.
The traffic disruption in San Diego, California, happened just after noon. Air traffic controllers at the airport tower stared at their monitors and saw that the system used to track incoming planes was down. Emergency pagers used to call doctors at the Naval Medical Center also stopped working. Traffic management systems used to guide ships also failed, threatening chaos at the busy port. On the street, people picked up their cell phones to find no signal, and bank customers who tried to withdraw cash from local ATMs were denied. The problem lasted another two hours.
The resolution of the mysterious incident from January 2007 took three days of inquiry. At that time, two Navy vessels were engaged in training exercises in the Port of San Diego. To test the emergency protocols for communication failures, technicians jammed radio signals. This action, however, unintentionally interfered with the GPS satellite signals across a broad area of the city.
Those satellite signals now do much more than inform your car's satellite navigation. GPS has become an "invisible utility" that we rely on without even realizing it. Cellphone companies use GPS time signals to coordinate how your phone talks to towers. Energy suppliers use GPS to synchronize grids when they link them together. Banks and stock exchanges use satellites to record timestamps to prevent fraud. Meanwhile, our society's reliance on GPS navigation grows by the day.
Some people worry that we're now too dependent on a technology that can easily fail - and that it doesn't take a crazy Navy exercise to wreak havoc. Their biggest concern is GPS jammers - plastic devices that can be placed on the dashboard of a car. These devices can be bought online and are often used by people like truck drivers who don't want their bosses to know where they are. Their increasing use has caused problems at airports and caused cellphone signal outages in several cities. If unblocked, a jammer can disrupt GPS from several kilometers away. So it's no surprise that researchers around the world are working to find ways to prevent catastrophic GPS outages from happening.
It is vital to understand that the failure of GPS systems today results in more than just navigation challenges. Donald Jewell, who has been a key contributor to the development of GPS in the U.S. Air Force and is presently the editor-in-chief of GPS World magazine, asserts that our dependence on GPS is often overlooked. He estimates that there are over a billion GPS receivers in use today, with more than 90 percent relying on the signals primarily for the precise timing they provide.
Cell phones are significant users of this stealth capability. As users travel, it is imperative for communication towers to coordinate with one another to transfer calls effectively, and GPS time signals provide a low-cost and accurate means to achieve this synchronization. The timing offset of each tower is also utilized for identification purposes. In fact, many wireless communication technologies depend on GPS timing for their synchronization needs. This reliance likely resulted in the disruptions experienced by traffic control and emergency pagers at the Port of San Diego in 2007.
Last deliberately simulated a simple, commercially available jammers. Although it’s illegal to use the low-tech devices in the United States, Britain and many other countries, they can be bought online for as little as $30. Sellers claim the devices are for privacy. Because they block devices that record a vehicle’s movements, they’re popular with truckers who don’t want electronic spies in their cabs. They can also block GPS-based road tolls levied through onboard receivers. Some criminals use them to hack trackers inside stolen cargo. “We initially thought the jammers might have been put together in the bedroom by a young man with pimples on his face,” Last says. “But now they’re being made in factories in China.”