Spacecraft provided with a device for estimating its velocity vector with respect to an inertial frame and corresponding estimation method

The spacecraft (1) has an estimation device (5) whose gyrometer (9) measures an instantaneous rotational velocity vector of the spacecraft relative to an inertial reference frame, and spatially spaced magnetometers (15) measure a vector of magnetic field produced by a celestial body. A computer (20) estimates a velocity vector of the spacecraft by solving an equation relating the instantaneous velocity vector to a time derivative and a spatial gradient of the field vector, a spacecraft position vector, and a rotational velocity vector of a reference frame with respect to the inertial frame. The celestial body is the Earth, and the magnetic field is terrestrial magnetic field. The reference frame is related to the celestial body and is a geocentric-equatorial reference frame. Independent claims are also included for the following: (1) a method for estimating a velocity vector relative to an inertial reference frame of a spacecraft (2) a method for determining a corrected velocity vector of a spacecraft.