AUTHORS: T. Sireesha, K. Krishna Murthy

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ABSTRACT: Fibre-Optic-Gyro (FOG) is an inertial-sensing device, determines the rotation-rate mainly working on the principle of Sagnac-effect. The accomplishment of inertial-grade-performance focused on an Interferometric Fibre-optic-Gyro (IFOG) with the closed-loop operation, but there are several drawbacks exist in analog-IFOG and finally considered the Digital Closed-Loop Interferometric Fibre-Optic-Gyro (DCLIFOG) and it mainly engage with bias-signal frequency and ramp signal (V2π voltage of IOC). The feedback signal uses a digital phase-ramp voltage to neutralize the gyro output. If the slight difference occurred in ramp and bias voltages, then founds the change in performance of gyro. Meanwhile, the dead-band occurs in DCLIFOG at low-rotation-rates, which is a significant phenomenon causes the nonlinearity output and also influences its accuracy. However, dead-band-error elimination is an important problem in DCLIFOG design, and suppresses the effect of dead-zone by a suitable resetting V2π voltage by controlling DAC reference-voltage. Here, different test-methods were proposed and considered for three-cases: (i) V2π (vary) & Vπ/2 (constant), (ii) Vπ/2 (vary) & V2π (constant) (iii) both V2π and Vπ/2 are varying simultaneously. This paper addresses the comparative analysis made on gyro-performance by evaluating its parameters among three-cases: the experimental results showed that the performance of gyro concerning with bias-stability, scale-factor linearity and also tremendously eliminated its dead-band.

KEYWORDS: - Digital Closed-loop Interferometric Fibre-Optic-Gyro (DCLIFOG); Ramp signal Voltage (V2π); Bias signal Voltage (Vπ/2); Dead-band or Dead-zone and Low-rotation-rates

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