Image: Ops Group

What’s New: Spoofing incidents which have seemed to be trying to lure aircraft into Iranian airspace, some have said near missile emplacements, have been found to likely be:

  • Coming from just outside Tehran.
  • Intended to deny GPS service rather than deceive aircraft and other users.

Why It’s Important: 

  • Poor navigation is always a safety issue, especially in aviation.
  • These incidents have revealed that the Internal Reference System (IRS) on many aircraft, that is supposed to be an independent navigation backup for GPS, is not independent. IRS equipment has been drawn off course also.
  • In 1983 poor navigation resulted in an aircraft being shot down and everyone aboard killed. Korean Air Flight 007 was shot down by the Soviets when it accidently crossed into their airspace. The incident prompted President Reagan to make GPS available for civil use.

What Else to Know:

  • Any kind of interference with GPS signals can manifest as spoofing. See the apparently accidental interference that almost caused a passenger aircraft to impact a mountain.
  • Sending fake GPS signals like this without trying to draw the user off course is called by some “smart jamming.” It can be more effective that “normal” jamming because receivers are likely to see the interference as valid signals and not reject them.
  • Good work by student Zach Clements and Prof. Todd Humphreys at Univ. of Texas Radionavigation Lab!



GPS Spoofing Signals Traced To Tehran

A University of Texas student has traced the source of alarming GPS spoofing signals in the Middle East to the eastern outskirts of Tehran, but it would seem there is little anyone can do to stop the navigation interference. Todd Humphreys, who heads up the Radionavigation Laboratory at UT, said the grad student, Zach Clements, was able to use gear on the International Space Station to scan for the bogus signals and approximate their source. He said analysis of the signals themselves suggests it’s a more sophisticated form of jamming, the cruder form of which is ubiquitous in the region. “They seemed to be aimed at denial of service rather than actual deception,” Humphreys told Vice. “My students and I came to realize that spoofing is the new jamming. In other words, it is being used for denial of service because it’s more effective for that purpose than blunt jamming.”