5/27/2016 August Schiess, Coordinated Science Laboratory
Written by August Schiess, Coordinated Science Laboratory
With the advent of GPS on our smartphones, using GPS signals as a wayfinding tool has become part of our everyday lives. Many things can interrupt this signal path, though, including benign obstacles like tall buildings, or malicious attacks from those trying to purposely distort the signal to cause harm.
The problem with current GPS positioning is it relies on at least four single connections between a receiver and a satellite. When the signal paths are distorted, the GPS fails to navigate properly, which could be disastrous for planes trying to safely land, for example.
To mitigate these signal interruptions, Aerospace Engineering at Illinois graduate student Yuting Ng, led by CSL Assisstant Professor Grace Gao, developed a technique that combines separate satellite signals into a single signal that is strong enough to offset any disruptions.
The technique is detailed in the paper “Mitigating Jamming and Meaconing Attacks Using Direct GPS Positioning,” which won Best Paper Award at the 2016 IEEE/ION Position Location and Navigation Symposium.
“Instead of analyzing them separately, this technique takes the power from all the signals to make a really strong peak that will rise above the noise,” said Ng. “So even if one signal is unavailable, the peak might shift a little bit, but it still provides a sufficient combined signal.”
The separate satellite signals combine to create a single peak—the best match for an accurate GPS signal that is strong enough to offset any disruptions.
The method, called Direct GPS Positioning (DP), was, at first, very computationally inefficient—it was not a practical method for everyday applications, like smartphones. However, Ng’s novel solution uses an architecture that accurately predicts position and velocity of the signals, which significantly improves computational efficiency.
Employing this technique will not only help prevent faulty GPS signals, but it will also specifically indicate if the signal is being intentionally attacked, thanks to advanced positioning and timing.
After developing this technique, Ng is working on new applications for this work, including integrating real-time street-view video with GPS directions.
“We are very excited to work in the area of GPS resilience and robustness, and help by pushing the research frontier forward,” said Gao, an assistant professor of aerospace engineering.