The Global Positioning System (GPS) that keeps drones in the air can be dangerous if it fails. Forbes.com reports on a recent incident in England where a drone strayed and crashed into a house. GPS interference is cited as the probable cause, although 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.
In this case, no one was injured and the damage to the house was minor, but it highlights the need for alternative drone operating mechanisms. “We need to start thinking about the overall architecture. What we need is a multi-layered architecture, with GPS and other satellites, something like eLoran for strong, terrestrial, hard-to-disturb regional coverage, and WiFi, cell towers, inertial systems, and other approaches for local layers. says Dana Goward, president and director of the Resilient Navigation and Timing Foundation.
Military-grade GPS jammers and spoofers can broadcast a fake location that can bring down a drone. GPS Block III, a $5 million program used by the US Air Force, isn't really suitable for civilian use, according to Goward. “GPS III offers jam-resistance improvements for military users with special equipment, but the 99% of civilian users will not experience any additional benefits at all,” Goward said. “Low power means [civilian] GPS is really, really, really easy to jam.”
As more drones take to the skies, GPS hazard identification will help prevent 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 goes into manual flight mode and hovers. Forbes noted that the downed English drone could not function properly without GPS guidance, disrupting its interpretation of the terrain and eventually crashing.