METHOD FOR MONITORING THE PERFORMANCE OF INERTIAL MEASUREMENT UNITS

A method of monitoring at least first and second inertial measurement units, the first inertial measurement unit and the second inertial measurement unit being connected to the same electronic processor circuit and being arranged to determine both a specific force vector in an accelerometer measurement reference frame and also rotation data concerning turning of the accelerometer measurement reference frame relative to an inertial reference frame; the electronic processor circuit performs the steps of projecting the specific force vectors into an inertial reference frame by using the rotation data; comparing the two specific force vectors as projected into said reference frame with each other in order to determine a difference between them; and monitoring variation in this difference over time.