Two fiber optic DTS systems were deployed and evaluated in oil and gas wells. Extended testing at 5,000 and 3,000 foot depths was performed to characterize the stability of the sensors. Long-term stability of less than 0.4°C rms and short-term stability of 0.05°C rms were observed. Ease of fiber optic sensor array deployment was proven, as well as the feasibility of remote real time monitoring of downhole temperature distributions.
KEYWORDS: Gyroscopes, Signal processing, Thermal modeling, Navigation systems, Sensors, Systems modeling, Global Positioning System, Digital signal processing, Instrument modeling, Calibration
A spherical error probable of 4.0 meters was demonstrated with an IFOG-based, integrated inertial measurement/global positioning system under dynamic field conditions. Less than 1.0 nautical mile per hour free inertial mode drift was also achieved with this system under laboratory-simulated test conditions. To achieve these levels of performance, IFOGs with bias uncertainties less than 0.015 deg/hr, scale factor errors less than 50 ppm and angle random walks less than 0.005 deg/(root) hr wee required. The performance of a series of six IFOGs is reported. For comparison, the performance of the same instruments measured in two demonstration GGP units is also presented. Both laboratory and field test results of the systems are discussed. The focus of the data presented is the instrument noise and the long term bias thermal model stability. The instruments and systems were developed as part of the first phase of a two phase program to create a 100 in 3 integrated GPS/INS systems with a target cost of 15K dollars (US). With the implementation of interferometric fiber optic gyro technology, integrated guidance and navigation systems are potentially very low cost with high reliability and suitability for a wide range of military and commercial applications.
Litton is developing an interferometric fiber optic gyroscope for future navigation, guidance, and stabilization applications. The gyro is presently less than three inches in diameter, which is size competitive with current ring laser gyros of equal performance. In this paper we report on the bias, scale factor, and input axis alignment performance of the inertial navigation fiber optic gyroscope over extended, dynamic temperature environments.
The paper examines the current status of Litton's design approach to the attitude-and-heading reference system interferometric fiber-optic gyro (IFOG). Theoretical models used to predict the IFOG bias performance over a temperature range are described. Data are presented for the performance of IFOGs over an extended environment. The combined test data on IFOGs and IFOG-based inertial measurement units (IMUs) obtained to date, along with the environmental performance and survivability data obtained with IFOG components of the type anticipated for production, support the prediction that low-production-cost IFOG-based systems are capable of meeting the performance requirements of medium-accuracy systems for near-future military applications.
Conference Committee Involvement (12)
Optical Waveguide and Laser Sensors II
1 May 2023 | Orlando, Florida, United States
Fiber Optic Sensors and Applications XVIII
4 April 2022 | Orlando, Florida, United States
Fiber Optic Sensors and Applications XVII
12 April 2021 | Online Only, Florida, United States
Optical Waveguide and Laser Sensors
27 April 2020 | Online Only, California, United States
Fiber Optic Sensors and Applications XVI
16 April 2019 | Baltimore, MD, United States
Fiber Optic Sensors and Applications XIII
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Fiber Optic Sensors and Applications XII
22 April 2015 | Baltimore, MD, United States
Fiber Optic Sensors and Applications XI
8 May 2014 | Baltimore, MD, United States
Fiber Optic Sensors and Applications X
2 May 2013 | Baltimore, Maryland, United States
Fiber Optic Sensors and Applications IX
26 April 2012 | Baltimore, Maryland, United States
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