T. Gaiffe, Y. Cottreau, N. Faussot, G. Hardy, P. Simonpiétri, H. Arditty
{"title":"Highly compact fiber optic gyrocompass for applications at depths up to 3000 meters","authors":"T. Gaiffe, Y. Cottreau, N. Faussot, G. Hardy, P. Simonpiétri, H. Arditty","doi":"10.1109/UT.2000.852533","DOIUrl":null,"url":null,"abstract":"Octans is a fiber-optic gyrocompass with an integral motion sensor developed by Photonetics for demanding marine applications. In contrast with conventional gyrocompasses relying on a spinning gyroscope, Octans has no moving parts and utilizes instead three fiber optic gyroscopes (FOG) and three quartz accelerometers. The FOG technology is based on the relativistic Sagnac effect: light travels in opposite directions into a fiber optic coil, and interferes at the output with a phase-shift proportional to the rotation rate. Moreover, three accelerometers measure, after Schuler filtering, the local gravity vector. As the FOGs are enough accurate (typically a bias stability of 0,05 /spl deg//h), the observation of the gravity slow drift in the inertial space allows one to determine the Earth axis, thus the North direction. In addition, the real three-axis architecture allows Octans to act as a marine motion sensor and compute the complete attitude of the vessel in terms of roll, pitch, heave, surge and sway. Because of a specific algorithm, Octans is able to find the true heading without any help in three minutes even at sea. This system is obviously ideal for ROVs and AUVs applications: low power consumption, compact, light box and very low settling time.","PeriodicalId":397110,"journal":{"name":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","volume":"38 5 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2000-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"40","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Proceedings of the 2000 International Symposium on Underwater Technology (Cat. No.00EX418)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/UT.2000.852533","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 40
Abstract
Octans is a fiber-optic gyrocompass with an integral motion sensor developed by Photonetics for demanding marine applications. In contrast with conventional gyrocompasses relying on a spinning gyroscope, Octans has no moving parts and utilizes instead three fiber optic gyroscopes (FOG) and three quartz accelerometers. The FOG technology is based on the relativistic Sagnac effect: light travels in opposite directions into a fiber optic coil, and interferes at the output with a phase-shift proportional to the rotation rate. Moreover, three accelerometers measure, after Schuler filtering, the local gravity vector. As the FOGs are enough accurate (typically a bias stability of 0,05 /spl deg//h), the observation of the gravity slow drift in the inertial space allows one to determine the Earth axis, thus the North direction. In addition, the real three-axis architecture allows Octans to act as a marine motion sensor and compute the complete attitude of the vessel in terms of roll, pitch, heave, surge and sway. Because of a specific algorithm, Octans is able to find the true heading without any help in three minutes even at sea. This system is obviously ideal for ROVs and AUVs applications: low power consumption, compact, light box and very low settling time.