SXSW 2013: Extreme GPS: Limits of Security & Precision

Todd Humphreys
Assistant Professor
The University of Texas at Austin

Presentation Description

GPS has its limits. My students and I at the University of Texas Radionavigation Lab work to find them. For 20 years, GPS was so reliable it became navigation and timing crack for engineers. We all got addicted. We put it in our phones, planes, power grid, comms networks. But there are limits.

My students and I bought an $80k helicopter drone a few months back and pushed its embedded GPS receiver to the extreme. Turns out, you can hijack one of these drones by perfectly aligning fake GPS signals with the real ones. And you can do it from miles away. We grabbed the world’s attention at White Sands in June. Our demo has changed the national conversation about integrating civil drones into the national airspace.

We want to probe the extremes again, only this time in precision. Surveyors already have hyper-precise GPS; we want to show how this can be commoditized, put in your cell phone, overlaid on the world. We want hyper-precise augmented reality.

Presentation Notes

On May2, 2000 President Clinton ordered that all GPS be changed from their accuracy of a football field, to what it is now.

GPS Jammers are an option you can use to prevent people from tracking you, since nowadays you can easily create and slap a tiny GPS on anyone or anything. These however are illegal to use a GPS Jammer (to turn it on), but not illegal to own one, or build one. These take about as much power as a 30 watt light bulb.

Texas has sensors to determine if people are using jammers on major bus routes. Strangely, they see about 5 different people per day using jammers driving through Texas. Sometimes jammers are used by people smuggling illegal drugs or items.

On December 4th, 2011 a missing drone was reported. Later it was found, in a gymnasium, in Iraq. So what happened? One of the engineers who produced the attack on the drone said it was an electronic attack to spoof it into thinking it was somewhere else.

GPS Spoofers don’t just jam GPS signals, but they spoof them into thinking they are somewhere else. It’s possible to do, as the Government decided to not encrypt or sign GPS packets, and they are fully open.

Todd and his team of students got the go-ahead from the National Homeland Security to test and implement a GPS Spoofer to take over the GPS coordinates of where a UAV thinks it is at. However, the NHS did not provide the UAV so they had to get funds to buy a used $80K UAV helicopter. They were able to do this, and overtake the UAV. Without permission from the NHS this would have been illegal otherwise. They now have a contract with the US Government to work on implementing “spoof-proof” specifications for any UAV over 18lbs.

Augmented Reality

Augmented Reality has a good concept, but they all require some sort of labels on an object for it to actually work. Even the Google Glass just slaps layers on your real life, and doesn’t meet these requirements:

  • A true 3D immersive experience
  • Virtual 3D elements that look and behave like real elements
  • Absolute cm-level registrations
  • Global reach, outdoors and indoors
  • Available soon

Handheld is fine; wearable is harder to implement and socially awkward anyhow. If someone looks at their watch while talking to you, you assume the conversation is about over. We recognize that the sensor suite in existing smartphones and tablets may be inadequate.

Carrier-Phase Differential GPS Positioning: Allows you to get down to distances by centimeter, or even millimeter if you’re close enough.

PTAM: allows you to determine distance, and position, on a grid system very accurately without GPS. This is locally defined, and not natively shared.