GPS spoofing - deceiving the navigation systems of devices that depend on GPS signals - is in the news more frequently. The loss of a U.S. spy drone over Iran, as well as some success in spoofing by research teams, has many concerned about the effectiveness and reliability of GPS for civilian and military applications.
Since the GPS satellite signal is relatively weak, and it comes from distant-orbiting satellites, there is some truth to the assumption that it can easily be overwhelmed or jammed by a similar signal from powerful ground or air-based stations. Jamming by overwhelming the GPS signal has been documented in war zones.
But GPS and drone navigation may be much more difficult to defeat than many assume it is. And there are technologies already available off-the-shelf (some of which are in your smartphone) to create a spoof-proof navigation system.
Let's take a look at what is being done, and additional measures that could be taken to create spoof-proof GPS. The United States Air Force 50th Space Wing, working with multiple contractors, has built and maintains the global GPS system.
The Space Wing has long been well-aware of GPS jamming, and made anti-jamming, advanced encryption, and increased signal power a key part of the specifications for new GPS satellites that are being launched each year. The so-called "GPS III" satellite specs "improve position, navigation and timing services and provide advanced anti-jam capabilities yielding superior system security, accuracy and reliability," states the main contractor, Lockheed Martin. "The first GPS III satellites will deliver signals three times more accurate than current GPS spacecraft and provide three times more power for military users." With some GPS III satellites nearing readiness for launch into orbit, the USAF and its partners have clearly been working on these issues for years.
Regarding anti-jamming, signal strength, and encryption, the word from experts is that even the new GPS III specs are being surpassed by the newest satellites under development, and that the USAF is letting the technology evolve to help prevent threats.
Backing Up GPS for Spoof-Proof Navigation
Even a toughened-up GPS signal may be vulnerable to some future threat. But there are multiple ways to prevent plane, ship, drone, etc. navigation from being completely fooled. Two of these technologies are already built into your smartphone. In addition to GPS, your phone already uses WiFi positioning to locate you when you can't get a GPS signal, and to speed up navigation and make it more accurate. While many ships, planes, and even cars operate far from WiFi signals, there are other signals in the air, for television, radio, etc. that can become part of a non-GPS positioning system to serve as a check-down and navigation backup.
Also on your smartphone is a little device called an accelerometer. On your phone, the accelerometer detects even very slight motion and stores it as data to be used by apps. Advanced accelerometers supported by powerful software have long been used in navigation systems, and they can store enough data to inform the user of location based just on motion data. So an accelerometer system, plus ambient signal location data, could provide excellent backup and emergency location data for any type of vehicle, craft, or weapon system.
Other Satellite Systems
In addition to the U.S.-managed GPS system, there are two other global satellite navigation systems in service: GLONASS, built and maintained by Russia, and the European Galileo system. Signals from these systems could provide yet another layer of backup to prevent complete GPS navigation spoofing.
Overall, there are multiple ways to prevent a navigation system from being spoofed, and military and commercial users are no doubt working on some or all of them. Ideally, any critical navigation system would have a quick way to detect spoofing attacks, and then be able to quickly check down position against other backups before being fooled into doing something harmful. The bottom line is that navigation systems are and will be much more difficult to spoof than many are assuming.