A gyroscopic system comprises at least four vibratory gyroscopes capable of changing vibration position. A first measurement is provided by a gyroscope to be calibrated and a second measurement is provided by a combination of the respective measurements from the other gyroscopes of the system, these first and second measurements being carried out along the same measurement axis. The determination (12) of a measurement drift value between the first measurement and the second measurement is followed by a command (13) to change the vibration position of the gyroscope to be calibrated to another vibration position and a drift value is again determined. The vibration position change command and the determination of a drift value are repeated (14) K times, K being a positive integer. Then, a drift model is generated (15) as a function of the vibration position of the gyroscope to be calibrated on the basis of the drift values obtained.