The Global Positioning System (GPS) that keeps drones aloft can be dangerous when it fails. Forbes.com reports on a recent incident in England where a drone went astray and crashed into a home. GPS interference is cited as the likely cause, though the source of the interference is not known. A “personal privacy device” or GPS jammer is a possible culprit. Jammers can be obtained online for less than $30, but it is unlawful to operate them in the U.K.
In this case, no one was injured and the damage to the house was minor, but it does highlight the need for alternate drone operating mechanics. “We need to start thinking about the overall architecture. What we need is a multi-layer architecture, with GPS and other satellites, something like eLoran for a strong, terrestrial, difficult-to-disrupt regional coverage, and WiFi, cell towers, inertial systems and other approaches for the local layers,” says Dana Goward, President and Director of the Resilient Navigation and Timing Foundation.
Military grade GPS jammers and spoofers can broadcast a false location that can down a drone. GPS Block III, a $5 million program used by the U.S. Air Force is not really adaptable for civilian use, according to Goward. “GPS III provides jam resistance improvements for military users with special equipment, but the 99 percent of users who are civilians won’t get much added benefit at all,” said Goward. “The low power means [civilian] GPS is really, really, really easy to jam.”
As more drones take to the skies, identifying GPS hazards will help stop drones from suddenly losing guidance and falling on people below. A satellite-guided GPS can be overwhelmed if a closer signal interrupts the satellite’s line of sight. What should happen when a drone loses contact with its GPS compass is that the drone switches to manual flight mode and hovers. Forbes noted the downed English drone could not function correctly without GPS guidance, confusing its interpretation of the terrain and ultimately crashing.