Step by step improvement of measurement methods for earth’s rotary rate using fiber optic gyro

Taking the ERR (earth’s rotary rate) measurement using FOG (fiber optic gyro) as an example, the methods to improve measurement accuracy, single-sample method, average method, dual-position method and VMM (vector modulation method) are discussed. average method can effectively eliminate the random errors in measurement systems. Dual-position method can remove the error of Bias in measurement systems. Following the Modulation–Demodulation principle and the linear system theory, especially the frequency-remaining character and the superposition theorem of linear systems, VMM was developed. VMM can effectively eliminate the measurement errors, which include quantization error, Bias, Drift, Noise and disturbance, and hereby improve the measurement accuracy. VMM works efficiently with most of the directional sensors.