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Results for “OPTICAL GYROSCOPE”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

Design and performance of a fiber optic gyroscope using integrated optics

Navigation grade fiber optic rotation sensors (FORS) are being developed as an alternative to spinning mass gyro's for unmanned planetary exploration spacecraft. FORS is attractive because of its many advantages such as long life, low weight, low power, and low cost as compared to its mechanical counterparts. FORS incorporates an advanced integrated optics circuit. The advanced eight-component integrated optics circuit performs all the key signal processing functions and in addition incorporates a unique optical beat detection circuit thereby providing an output in the form of pulses proportional to incremental angular position similar to a ring laser gyro (RLG) but without the inherent lock-in problem RLG's possess.

Youmans, B. R.↗
NASA NTRS1990

Fiber optic gyroscope using an eight-component LiNbO3 integrated optic circuit

A LiNbO3 integrated optic circuit (IOC) containing eight optical functions has been successfully incorporated into an interferometric fiber optic gyroscope. The IOC has the minimum configuration optical functions (a phase modulator, a polarizer, and two beam splitters) and Jet Propulsion Laboratory's novel beat detection circuit (a phase modulator, two optical taps, and a beam splitter) which provides a means of directly reading angular position and rotation rate. The optical subsystem consisting of the fiber-pigtailed IOC and a sensing coil of 945 meters of polarization-maintaining fiber has a loss of 18.7dB, which includes 9dB due to the architecture and unpolarized source. A random walk coefficient was measured using an edge-emitting LED as the source.

Minford, W. J.↗
NASA NTRS1993

NASA's first in-space optical gyroscope: A technology experiment on the X ray Timing Explorer spacecraft

A technology experiment on the X-ray Timing Explorer spacecraft to determine the feasibility of Interferometric Fiber Optic Gyroscopes for space flight navigation is described. The experiment consists of placing a medium grade fiber optic gyroscope in parallel with the spacecraft's inertial reference unit. The performance of the fiber optic gyroscope will be monitored and compared to the primary mechanical gyroscope's performance throughout the two-year mission life.

Unger, Glenn↗
NASA NTRS1979

Fiber Ring Optical Gyroscope (FROG)

The design, construction, and testing of a one meter diameter fiber ring optical gyro, using 1.57 kilometers of single mode fiber, are described. The various noise components: electronic, thermal, mechanical, and optical, were evaluated. Both dc and ac methods were used. An attempt was made to measure the Earth rotation rate; however, the results were questionable because of the optical and electronic noise present. It was concluded that fiber ring optical gyroscopes using all discrete components have many serious problems that can only be overcome by discarding the discrete approach and adapting an all integrated optic technique that has the laser source, modulator, detector, beamsplitters, and bias element on a single chip.

Source record↗
NASA NTRS1981

Optical gyroscope system

Light beams pass in opposite directions through a single mode fiber optic wave guide that extends in a circle or coil in an optical gyroscope system which measures the rotation rate of the coil by measuring the relative phase shifts of the beams by interferometric techniques. Beam splitting and phase shifting of the light are facilitated by utilizing brief pulses of light and by using light-controlling devices which are operated for a brief time only when the light pulse passes in one direction through the device but not at a different time when the pulse is passing in the opposite direction through the device. High accuracy in rotation measurement is achieved at both very slow and very fast rotation rates, by alternately operating the system so that at zero rotation the interfering waves are alternately 90 out of phase and in phase. Linear polarization of the light beams is maintained by coiling the full length of the optic fiber in a single plane.

Goss, W. C.↗
NASA NTRS1978

Optical gyroscope

Instrument uses phase difference between two beams of light to measure rotation. It is considerably simpler and more reliable than conventional spinning-mass gyroscopes used for inertial guidance and is more compact, lighter, and potentially less expensive. Moreover, optical gyroscope requires no warmup period. Although conceived for spacecraft and satellite stabilization, gyroscope should also find applications in flight instruments for private, commercial, and military aircraft.

Goldstein, R. M.↗
NASA NTRS1978

Fresnel drag effect in fiber optic gyroscope

Consideration is given to the development of a low-noise fiber-optic ring interferometer gyroscope. A technique for measuring the Fresnel drag coefficient of optical fibers is described, and the accuracy of the technique is considered. An experiment is performed which allows verification of the Einstein velocity addition theorem to the first nonlinear term. An experimental setup for measuring Fresnel drag is described: it consists of a Sagnac interferometer and a Fresnel drag measurement configuration.

Vali, V.↗
NASA NTRS1990

Interferometric Fiber-Optic Gyroscope

Integrated three-waveguide directional coupler functions as polarizer and splitter. Designed with transverse electric (TE) polarization in bar state (two coupling lengths) and transverse magnetic (TM) polarization in cross state (one coupling length). Intended for eventual fabrication as in mass-producible integrated optical circuit that provides advantages including low drive voltage, large-bandwidth phase modulation, preservation of polarization in transmission between devices on same substrate, and low cost.

Depaula, Ramon P.↗
NASA NTRS2015

Fast Light Optical Gyroscopes

Next-generation space missions are currently constrained by existing spacecraft navigation systems which are not fully autonomous. These systems suffer from accumulated dead-reckoning errors and must therefore rely on periodic corrections provided by supplementary technologies that depend on line-of-sight signals from Earth, satellites, or other celestial bodies for absolute attitude and position determination, which can be spoofed, incorrectly identified, occluded, obscured, attenuated, or insufficiently available. These dead-reckoning errors originate in the ring laser gyros themselves, which constitute inertial measurement units. Increasing the time for standalone spacecraft navigation therefore requires fundamental improvements in gyroscope technologies. One promising solution to enhance gyro sensitivity is to place an anomalous dispersion or fast light material inside the gyro cavity. The fast light essentially provides a positive feedback to the gyro response, resulting in a larger measured beat frequency for a given rotation rate as shown in figure 1. Game Changing Development has been investing in this idea through the Fast Light Optical Gyros (FLOG) project, a collaborative effort which began in FY 2013 between NASA Marshall Space Flight Center (MSFC), the U.S. Army Aviation and Missile Research, Development, and Engineering Center (AMRDEC), and Northwestern University. MSFC and AMRDEC are working on the development of a passive FLOG (PFLOG), while Northwestern is developing an active FLOG (AFLOG). The project has demonstrated new benchmarks in the state of the art for scale factor sensitivity enhancement. Recent results show cavity scale factor enhancements of approx.100 for passive cavities.

Smith, David D.↗
NASA NTRS1990

Fiber optic and laser sensors VII; Proceedings of the Meeting, Boston, MA, Sept. 5-7, 1989

Various papers on fiber optic and laser sensors are presented. Individual topics addressed include: fiber optic photoelastic pressure sensor for high-temperature gases, fiber optic gyroscope using an eight-component LiNbO3 integrated optic circuit, design and performance of a fiber optic gyroscope using integrated optics, digital angular position sensor using wavelength division multiplexing, simple repeatable fiber optic intensity sensor for temperature measurement, compensation for effects of ambient temperature on rare-earth-doped fiber optic thermometer.

Udd, Eric↗
NASA NTRS1991

Fiber optic and laser sensors VIII; Proceedings of the Meeting, San Jose, CA, Sept. 17-19, 1990

This issue presents topics on the advances in fiber-optic sensor technology, fiber-optic gyroscope, fiber-optic position and pressure sensors, fiber-optic magnetic and temperature sensors, and generic fiber-optic sensors. Papers included are on a novel analog phase tracker for interferometric fiber-optic sensor applications, recent development status of fiber-optic sensors in China, the magnetic-field sensitivity of depolarized fiber-optic gyros, a depolarized fiber-optic gyro for future tactical applications, fiber-optic position transducers for aircraft controls, and a metal embedded optical-fiber pressure sensor. Attention is also given to a fiber-optic magnetic field sensor using spectral modulation encoding, a bare-fiber temperature sensor, an interferometric fiber-optic accelerometer, improvement of specular reflection pyrometer, a theoretical analysis of two-mode elliptical-core optical fiber sensors, and a fiber probe for ring pattern.

Depaula, Ramon P.↗
NASA NTRS1984

Fiber optic sensors

A survey of the developments in the field of fiber optics sensor technology is presented along with a discussion of the advantages of optical measuring instruments as compared with electronic sensors. The two primary types of fiber optics sensors, specifically those with multiwave fibers and those with monowave fibers, are described. Examples of each major sensor type are presented and discussed. Multiwave detectors include external and internal fiber optics sensors. Among the monowave detectors are Mach-Zender interferometers, Michelson interferometers, Sagnac interferometers (optical gyroscopes), waveguide resonators, and polarimeter sensors. Integrated optical sensors and their application in spectroscopy are briefly discussed.

Hesse, J.↗
NASA NTRS2008

Nuclear-Spin Gyroscope Based on an Atomic Co-Magnetometer

An experimental nuclear-spin gyroscope is based on an alkali-metal/noblegas co-magnetometer, which automatically cancels the effects of magnetic fields. Whereas the performances of prior nuclear-spin gyroscopes are limited by sensitivity to magnetic fields, this gyroscope is insensitive to magnetic fields and to other external perturbations. In addition, relative to prior nuclear-spin gyroscopes, this one exhibits greater sensitivity to rotation. There is commercial interest in development of small, highly sensitive gyroscopes. The present experimental device could be a prototype for development of nuclear spin gyroscopes suitable for navigation. In comparison with fiber-optic gyroscopes, these gyroscopes would draw less power and would be smaller, lighter, more sensitive, and less costly.

Romalis, Michael↗
NASA NTRS2001

Mechanisms for the Crystallization of Zblan

The heavy metal fluoride glasses represent a class of reasonably good glass forming compositions with very unique infrared optical properties that have been of interest to researchers for 20 years. The most extensively studied glass with the most potential for practical applications is ZBLAN which contains the fluorides of zirconium, barium, lanthanum, aluminum, and sodium. It has a broad transmission range (0.3-6 um), low index of refraction (about 1.43), low dispersion, low Raleigh scattering, ultra-low thermal 2 dispersion, and potential ultra-low signal attenuation. Potential applications include fiber amplifiers, fiber optic gyroscopes, delivery systems for laser cutting, drilling and surgery, radiation resistant data links, nonlinear optical systems, and ultra-low-loss repeater-less transcontinental and transoceanic optical fiber. Potential markets for these materials are in the tens of billions of dollars per year. Optical fiber from this system possess excellent transmission characteristics in the IR, but the glass is somewhat susceptible to nucleation and crystallization. The theoretical intrinsic loss coefficient for ZBLAN at 2 microns is 0.00 1 dB/Km. Extrinsic losses, however, cause significant attenuation. The lowest loss coefficient measured is 0.7 dB/Km. This compares with the loss coefficient for fiber optic grade fused silica glass of 0.2 dB/Km. The extrinsic losses in ZBLAN have been attributed to 1) impurities which might be lowered by containerless processing and 2) to scattering from micro-crystallites that form during glass preform production or during fiber drawing.

Ethridge, Edwin C.↗
NASA NTRS1988

Optical Isolator For Use With Single-Mode Fiber

Assembly of commercially available components acts as single-mode fiber-optic isolator with lower forward-transmission loss and higher attenuation of reverse transmission than previously achieved in single unit. New design reduces cost and improves performance of optical gyroscopes, precise time- and frequency-signal-distribution systems, and other systems that include fiber optics and isolators.

Lutes, George F.↗
NASA NTRS1987

Closed loop fiber optic rotation sensor

An improved optical gyroscope is provided, of the type that passes two light components in opposite directions through an optic fiber coil, and which adds a small variable frequency to one of the light components to cancel the phase shift due to rotation of the coil. The amount of coil rotation from an initial orientation, is accurately determined by combining the two light components, one of which has a slightly increased frequency, to develop beats that each represent a predetermined angle of rotation. The direction of rotation is obtained by combining the two light components on a photodetector, intermittently phase shifting a single light component by 90 deg and comparing the direction of change of photodetector output (+ or -) caused by the 90 deg shift, with the slope (+ or -) of the photodetector output at about the same time, when there is a 90 deg shift.

Goss, Willis C.↗