GPS spoofing
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GPS spoofing is an attack in which false satellite navigation signals are broadcast to trick a receiver into computing a wrong position or time. Because civilian GPS signals are weak and unauthenticated, a transmitter can overpower the genuine signals and feed a device fabricated coordinates. Spoofing differs from jamming: jamming denies a position fix, while spoofing supplies a convincing but incorrect one.
How it works
A GPS receiver calculates its location by measuring the timing of signals from multiple satellites. Civilian signals follow a public format and carry no cryptographic authentication, so a receiver cannot inherently tell a genuine signal from a forged one. A spoofer transmits counterfeit signals that mimic the satellites, and if they are stronger and well-crafted, the receiver locks onto them and reports whatever position and time the attacker chooses.
More sophisticated spoofing aligns the fake signals with the real ones and then gradually pulls the receiver away, so the reported position drifts smoothly and does not trigger obvious alarms. Because the same signals also distribute precise time, spoofing can disrupt systems that depend on accurate timing, not only those that depend on location.
Why it matters
Many systems trust GPS implicitly, including vehicles, drones, ships, and timing infrastructure. A successful spoof can misdirect an autonomous system, falsify a recorded location, or desynchronize time-dependent equipment. Detecting spoofing is difficult precisely because the receiver still gets a clean, plausible fix.
Mitigations include cross-checking GPS against independent sensors such as inertial units, monitoring signal characteristics for anomalies, and using authenticated signals where available. The broader lesson is that a single, unauthenticated source of position or time is a fragile foundation for anything that must keep working under attack.
How it relates to Offline Protocol
Offline Protocol matters most where GPS cannot be trusted or is unavailable at all, such as GPS-denied and GPS-degraded environments. Rather than relying solely on satellite coordinates, a device can reason about where it is relative to the mesh around it, using which peers it can reach and over how many hops. This topology-based view gives a position signal that does not come from GPS and so is not undone by a spoofed satellite fix.
This is central to robotics and autonomous operations, where a spoofed position can be dangerous. See robotics for GPS-denied coordination, and proof of location for how peer relationships in the mesh support location claims that do not depend on GPS alone.
Frequently asked questions
What is GPS spoofing?
It is an attack that broadcasts fake satellite signals to make a GPS receiver report a false position or time, exploiting the fact that civilian GPS signals are weak and unauthenticated.
How is spoofing different from jamming?
Jamming denies a fix by drowning out GPS signals, while spoofing supplies a convincing but incorrect fix. Spoofing is often harder to detect because the receiver still reports a clean position.
How does Offline Protocol help in GPS-denied settings?
It lets devices reason about position from mesh topology, which peers they can reach and over how many hops, giving a location signal that does not depend on GPS and is not undone by a spoofed satellite fix.
