A method calibrates an inertial-sensor device installed in an arbitrary position on board a vehicle and adapted to detect at least one entity indicative of vehicle dynamics along at least one direction of a local reference-coordinate system. The method includes steps of: acquiring by the inertial-sensor device at predetermined measuring times real-measured data indicative of the vehicle dynamics in the local reference-coordinate system; acquiring by a calibrating detector different from the inertial-sensor device, at sampling times coinciding with the measuring times, reference-measured data indicative of the vehicle dynamics in a vehicle-coordinate system; and generating a coordinate-transformation matrix adapted to correlate the entity measured in the local reference-coordinate system with a corresponding entity in the vehicle-coordinate system. Also, a sensor system of dynamics of the vehicle is able to be installed on board in an arbitrary position.