Russia is jamming GPS from space

“America is at risk of high impact GPS jamming and spoofing from space” was the title of my SpaceNews opinion article in October 2024. Little did I know that its publication would set into motion a series of events that ended up proving Russia has been jamming GPS from space since 2019. In the 2024 article, I quoted remarks at a conference by Professor Todd Humphreys from the University of Texas Radionavigation Lab. I included additional speculation by Todd, me and my colleague General William Shelton, USAF (ret), one time commander of Air Force Space Command, about China’s and Russia’s space-based capabilities. Shortly after it was published, I was surprised to be contacted by a researcher in the United Kingdom. He said that interference from space was more than a possibility — he had observed it. Examining data from terrestrial reference stations operated by the International Global Navigation Satellite System (GNSS) Service, he had noticed instances in which GPS signal strength had decreased markedly. In each case it was for less than ten seconds, but the events had been recorded by stations across a very broad section of northern Europe. While he did not want to be publicly identified, the researcher did agree to the Resilient Navigation and Timing Foundation putting him in touch with others who could confirm his findings and perhaps discover more. He also agreed to General Shelton and I giving his data to officials in the United States government. We did that in November 2024 in multiple meetings with the administration and one with an interested congressional staff member. Of the other researchers we contacted, Humphreys and his team at the University of Texas were particularly interested. Eventually they were able to use data from 165 reference stations across Europe, Greenland and Canada to independently verify the UK researcher’s findings. The University of Texas team identified 75 instances of interference between 2019 and 2026 in which there were significant decreases in carrier to noise ratio (CNR) of 5dB or more. A year after being put onto the scent, Humphreys and his research student Zach Clements had confirmed the interference was coming from space and presented a paper with their findings, published September 2025 in the journal Proceedings of the 38th International Technical Meeting of the Satellite Division of the Institute of Navigation. But they had not been able to identify which of numerous possible satellites were responsible. In preprint research paper released in May, “Chasing Lightning: Detecting, Characterizing, and Identifying a Powerful Space-Based GNSS Interference Source,” Humphreys and Clements at Texas, and Argyris Kriezis from Stanford, explain how they found the culprit — a small constellation of Russian early warning satellites in Molniya (lightning) orbits. Humphreys is confident that the interference is purposeful, not hardware malfunctions or accidental emissions. “The pattern is far too consistent for this…