Analysis of dead zone sources in a closed-loop fiber optic gyroscope

Abstract

Analysis of the dead zone is among the intensive studies in a closed-loop fiber optic gyroscope. In a dead zone, a gyroscope cannot detect any rotation and produces a zero bias. In this study, an analysis of dead zone sources is performed in simulation and experiments. In general, the problem is mainly due to electrical cross coupling and phase modulation drift. Electrical cross coupling is caused by interference between modulation voltage and the photodetector. The cross-coupled signal produces spurious gyro bias and leads to a dead zone if it is larger than the input rate. Phase modulation drift as another dead zone source is due to the electrode contamination, the piezoelectric effect of the LiNbO3 substrate, or to organic fouling. This modulation drift lasts for a short or long period of time like a lead-lag filter response and produces gyro bias error, noise spikes, or dead zone. For a more detailed analysis, the cross-coupling effect and modulation phase drift are modeled as a filter and are simulated in both the open-loop and closed-loop modes. The sources of dead zone are more clearly analyzed in the simulation and experimental results.

Research on Measurement Technology of Ship Leakage Current by All-Fiber Optic Current Sensor

“…The closed-loop demodulation scheme has many advantages, such as an extended dynamic range and insensitivity to light intensity. However, when the measurement rotation angle is slight, the phenomenon of "dead zone" is prone to occur for closed-loop feedback demodulation [23]. Therefore, the open-loop demodulation scheme is more suitable for small current measurements.…”

Projeto e implementação de um sistema eletrônico para giroscópios interferométricos a fibra óptica de malha fechada

“…Conforme discutido na Seção 2.2.2.1, o crosstalk entre os circuitos de modulação e demodulação do giroscópio é, segundo vários autores[47][48][49][50][51], a principal causa de zona-morta nos IFOGs. O emulador do conjunto óptico permitiu a realização de um experimento para verificação da interferência do circuito de modulação no circuito de aquisição do giroscópio.…”