A Low-Drift Laser-Driven FOG Suitable for Trans-Pacific Inertial Navigation

We report a laser-driven fiber-optic gyroscope (FOG) with an angle random walk of 0.9 mdeg/√h, an Allan-deviation minimum of 4.9 mdeg/h, and an Allan-deviation maximum (or true drift) of 12.6 mdeg/h. This state-of-the-art performance was achieved by implementing an optical gate and a power-control feedback loop to suppress several sources of drift in the FOG, namely optical spikes that result from the square-wave biasing modulation, the nonlinear Kerr effect, drift in the detected power arising from spurious interferometers in the fiber circuit and laser-power fluctuations, and bias offset drift in the demodulation electronics. The measured output of this FOG was used to simulate 20 10-h trans-Pacific flights of an aircraft guided solely by inertial sensors. 95% of the flights landed within ±10 nmi of their intended destination. To our knowledge, this is the first report of a laser-driven FOG that meets the Federal Aviation Administration's Required Navigation Performance 10 criteria for aircraft navigation.