FIBRE-OPTIC MEASUREMENT DEVICE, RATE GYRO, AND INERTIAL STABILISATION AND NAVIGATION UNIT

摘要

A fibre-optic measurement device (10) includes a SAGNAC ring interferometer (20) having a proper frequency fp, a detector (14) and a modulation chain (30) generating a phase-shift modulation &phgr;m(t) between the two counter-propagating waves (24, 25) propagating in the ring interferometer. The device aims to reduce measurement faults due to the linearity defects in the modulation chain of such a measurement device with optical fibre. For this reason, the fibre-optic measurement device reduces the amplitude of the phase-shift modulation &phgr;m(t) which is the sum of a first biasing phase-shift modulation component &phgr;b1(t) and a first counter-reaction phase-shift modulation component &phgr;cr1(t), the phase-shift modulation &phgr;m(t) falling or rising by twice the amplitude of the first biasing phase-shift modulation component &phgr;b1(t). A rate gyro including such a measurement device and an inertial stabilization or navigation unit including at least one such rate gyro are also described.