GPS spoofing — broadcasting fake satellite signals to deceive receivers — is a growing problem in contested environments. Military spoofing can redirect ships, mislocate aircraft, and corrupt timing infrastructure. Detecting spoofing from a single receiver is hard because the fake signals mimic the real ones. But the global shipping fleet broadcasts its position continuously via the Automatic Identification System (AIS), creating a dense network of position reports that can be cross-referenced.
The paper (arXiv:2603.11055) uses AIS-derived ship positions as an independent truth source to detect GPS spoofing and jamming across wide areas. If a ship's GPS-derived position suddenly disagrees with its AIS track (which aggregates data from multiple sources including coastal radar and satellite AIS), the discrepancy flags potential spoofing. When multiple ships in the same area show correlated position jumps, the detection becomes high-confidence.
The inversion is elegant: the shipping fleet, which depends on GPS for navigation, becomes the sensor that detects GPS attacks. Each ship is an unwitting probe in a distributed monitoring network. The density of maritime traffic in shipping lanes means the sensor network is densest exactly where spoofing would cause the most disruption — near ports, in straits, along major trade routes.
The spatiotemporal analysis distinguishes spoofing from jamming. Jamming causes GPS outages — ships lose their fix. Spoofing shifts positions coherently — ships report being somewhere they're not. The pattern of AIS anomalies — scattered dropout versus coordinated displacement — identifies which attack is occurring, where the spoofing signal originates, and how large an area is affected.