GPSSpoofing

GPS spoofing is the deliberate transmission or presentation of counterfeit Global Positioning System signals with the aim of deceiving a receiver about its position, velocity, or time. It is distinct from jamming, which simply blocks signals, and from meaconing, where legitimate signals are recorded and replayed with delay. Spoofing can be conducted with a range of sophistication, from low‑power, improvised signals to coordinated, multi‑satellite deception that can withstand some receiver checks.

Spoofing works by generating a counterfeit GPS signal that appears authentic to a target receiver. Attackers may use software‑defined radios, GNSS simulators, or portable spoofing devices to control the code phase and Doppler of fake satellites. Near‑field spoofing places a transmitter close to the victim and gradually increases the counterfeit signal power; remote spoofing uses directional antennas and carefully staged signals to entice the receiver to track the counterfeit constellation while drifting its computed position or time. Civilian systems may not have authentication, so spoofers exploit the lack of end‑to‑end verification.

Impacts are broad because GPS provides navigation and time for aviation, maritime, vehicles, power grids, financial networks, and communications. Spoofing can cause misnavigation, unsafe landings, timing errors, and damage to safety‑critical operations or infrastructure.

Countermeasures include detector algorithms in receivers, cross‑checking with inertial measurement units or other timing sources, and the use of multi‑constellation receivers. Some GNSS modernization efforts consider navigation message authentication, and researchers are exploring cryptographic authentication and physical‑layer defenses, such as directional antennas and monitoring networks.