Starlink signals can be reverse-engineered to work like GPS

A team of researchers from the University of Texas Austin (UTA) have shown the Starlink broadband constellation’s potential to serve as a backup for GPS.

The researchers, led by Todd Humphreys and funded by the U.S. Army, examined the downlink signal structure of the SpaceX Starlink constellation of ultrafast broadband satellites in low-Earth-orbit (LEO), reported MIT Technology Review. The team showed that Starlink could serve as a useful backup to GPS.

For the past two years, Humphreys’ team at UT Austin’s Radionavigation Lab has been reverse-engineering signals sent from thousands of Starlink internet satellites to ground-based receivers. Humphreys told the review that regular beacon signals from the constellation, designed to help receivers connect with the satellites, could form the basis of a useful navigation system.

SpaceX opted not to participate in the research.

Read the research paper here.

Title: Signal Structure of the Starlink Ku-Band Downlink

Authors: Todd E. Humphreys, Peter A. Iannucci, Zacharias Komodromos, Andrew M. Graff

Abstract: We develop a technique for blind signal identification of the Starlink downlink signal in the 10.7 to 12.7 GHz band and present a detailed picture of
the signal’s structure. Importantly, the signal characterization offered herein includes the exact values of synchronization sequences embedded in the
signal that can be exploited to produce pseudorange measurements. Such an understanding of the signal is essential to emerging efforts that seek to dual-purpose Starlink signals for positioning, navigation, and timing, despite their being designed solely for broadband internet provision.