Abstract: A method and system for measuring a vehicle airspeed, wherein a nuclear magnetic resonance, NMR, measurement method is used for obtaining relative velocity between the vehicle and an atmosphere surrounding the vehicle. A groove is arranged at the outside body of an aircraft and the surrounding atmosphere is allowed to pass inside the groove. A strong magnet system establishes a magnetic field with a gradient in the flow direction. The atoms passing inside the groove is exposed to an electromagnetic radiation whereby the atoms oscillate at a Lamor frequency, which is proportional to the strong magnetic field. The change in Lamor frequency along the groove is measured and is proportional to the airspeed.