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Fibre-optic gyroscope for car navigation systems
Abstracts Measurement of two-dimenslonal strain distribution by speckle correlation
Akihiro Ooka, Yozo Nishiura, Kouichi Washimi, Kenfi Okamoto
Seokho Noh, lchirou Yamaguchi
S u m i t o m o Electric Industries, Ltd.
The Institute of Physical and Chemical Research, Saitama University 9th Meeting on Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society of Applied Physics Electronic speckle pattern correlation is applied to the measurement of two-dimensional in-plane displacement and strain distributions. Image speckle patterns are taken by a CCD camera and stored in a frame memory with 512 x 480 pixels. These images are divided into blocks, each of which contains 64 x 64 pixels. From the peak positions of the two-dimensional cross-correlation of each block image before and after deformation, speckle displacements in each block are derived. Strain components are calculated from differentiation of the displacement. If there are some surface defects in the specimen, the peak of the two-dimensional cross-correlation is blurred. To measure the twodimensional displacement of the specimen in this ease, we extract the sketch features of the defect regions using a DIP operator and we calculate the histogram of all the combinations of the distance vectors between the edge pixels.
9th Meeting o n Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society o f Applied Physics As a world first, we have developed a fibre-optic gyroscope for use as the car navigation system in mass-produced vehicles. Fibre-optic gyroscopes have been the preferred type of rotation rate sensor for navigation systems, but were not previously realistic due to the cost and mass production problems. Our new gyroscope is used by Nissan Motor Co in systems installed in their Cedric, Gloria and Cima models. The gyroscope consists of all fibre components for increased reliability. Performance over a wide temperature range is assured by a compensating signal processing circuit. The car navigation system built around these fibre-optic gyroscopes offers significantly enhanced position detection accuracy when compared with conventional systems.
Bread board model of the passive ring resonator fibre-optic gyro
Tohru Imai, Nishide Ken-ichi, Motoichi Ohtsu* T o k y o Aircraft I n s t r u m e n t Co, Ltd. *Tokyo Institute of Technololgy
Fibre-optic gyros
Kazuo Hotate Research Center for A d v a n c e d Science a n d (RCAST), The University o f T o k y o
Fibre-optic gyroscope for ear navigation systems
Technology
9th Meeting o n Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society of Applied Physics Research and development of fibre-optic gyros is described. An interferometer fibre-optic gyro, I-FOG for short, is now at the stage of practical applications. A car navigation system, rocket launching, train routeing, gyrocompass for seeking north and other applications have been tried. An open-loop configuration, which corresponds to rate tyro, is used in the above applications. On the other hand, a closed-loop configuration corresponding to rate integration tYro, which can meet specification for high-grade aircraft navigation, has also been developed. The second type, the resonator fibre-optic gyro; R-FOG, is attractive because the length of the sensing fibre coil can be shortened to be less than 10 m. Noise characterization has been carried out. A fibre-optic ring laser gyro, F-RLG is also promising, in which Brillouin scattering in a fibre resonator produces laser oscillation. This type may have a possibility to provide a quite simple configuration.
Car navigation system using a fibre-optic gyroscope the development of a new navigation system (multi AV system)
Shinya lshikawa Nissan M o t o r Co. 9th Meeting o n Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society o f Applied Physics The new navigation system, the Multi AV system, is available in the 1991 Cedric, Gloria and Cima models. We developed this system, attaching importance to accuracy, operation and safety. A fibre-optic gyroscope was employed in mass-production cars and remarkably improved precise positioning. Furthermore, the new map-matching logic covering all Japan was developed and the database of the map was expanded. Therefore, this system has a great practical use.
9th Meeting on Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society of Applied Physics The passive ring resonator fibre-optic gyro (RFOG) using a FM spectroscopy technique is described. RFOG requires not only a highcoherence light source but also a high finesse fibre ring resonator. Therefore, a highly coherent laser diode module (HCLDM) with 100 kHz linewidth has been developed using the optical feedback from a hemispherical reference cavity. A l0 m length fibre ring resonator with finesse 91 has been developed, in which the principal axes of the fibre were rotated by an angle of 90 ° with respect to each other. The FM spectroscopy technique was employed in order that the system could have a higher sensitivity, a wider bandwidth and a lower influence from the IM noise of the LD than the lock-in detection technique. From a signal-to-noise ratio of the demodulated signal, the resolution of the bread board model was estimated to be 0.04 ° hr(the integration time of measurement is 10 s).
Serrodyne fibre-optic gyroscope with high-scale factor performance
Sadaomi Sakuma, Shin-ichi Kawada, Toshiyuki Muroi, Isao Masuzawa, Shigeru Nakamura, Yoshiaki lmamura, Takao Sagawa Tokimec Inc 9th Meeting o n Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society of Applied Physics This paper describes the prototype serrodyne fibre-optic gyroscope for an attitude and heading reference system. It has an integrated optic chip which incorporates a Y-branch coupler, a polarizer and electrodes for phase modulation, and operates at a wavelength of 830 nm. Closedloop computer simulation and calculation are performed to develop a new technique which markedly reduces the scale-factor error due to the imperfect solodyne-driving wavcform. Current scale factor performance of the gyroscope with a polarization maintaining 150 m sensing coil is presented.
Optics 8t Laser Technology 262
Vol 25 No 4 1993
Akihiro Ooka, Yozo Nishiura, Kouichi Washimi, Kenfi Okamoto
Seokho Noh, lchirou Yamaguchi
S u m i t o m o Electric Industries, Ltd.
The Institute of Physical and Chemical Research, Saitama University 9th Meeting on Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society of Applied Physics Electronic speckle pattern correlation is applied to the measurement of two-dimensional in-plane displacement and strain distributions. Image speckle patterns are taken by a CCD camera and stored in a frame memory with 512 x 480 pixels. These images are divided into blocks, each of which contains 64 x 64 pixels. From the peak positions of the two-dimensional cross-correlation of each block image before and after deformation, speckle displacements in each block are derived. Strain components are calculated from differentiation of the displacement. If there are some surface defects in the specimen, the peak of the two-dimensional cross-correlation is blurred. To measure the twodimensional displacement of the specimen in this ease, we extract the sketch features of the defect regions using a DIP operator and we calculate the histogram of all the combinations of the distance vectors between the edge pixels.
9th Meeting o n Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society o f Applied Physics As a world first, we have developed a fibre-optic gyroscope for use as the car navigation system in mass-produced vehicles. Fibre-optic gyroscopes have been the preferred type of rotation rate sensor for navigation systems, but were not previously realistic due to the cost and mass production problems. Our new gyroscope is used by Nissan Motor Co in systems installed in their Cedric, Gloria and Cima models. The gyroscope consists of all fibre components for increased reliability. Performance over a wide temperature range is assured by a compensating signal processing circuit. The car navigation system built around these fibre-optic gyroscopes offers significantly enhanced position detection accuracy when compared with conventional systems.
Bread board model of the passive ring resonator fibre-optic gyro
Tohru Imai, Nishide Ken-ichi, Motoichi Ohtsu* T o k y o Aircraft I n s t r u m e n t Co, Ltd. *Tokyo Institute of Technololgy
Fibre-optic gyros
Kazuo Hotate Research Center for A d v a n c e d Science a n d (RCAST), The University o f T o k y o
Fibre-optic gyroscope for ear navigation systems
Technology
9th Meeting o n Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society of Applied Physics Research and development of fibre-optic gyros is described. An interferometer fibre-optic gyro, I-FOG for short, is now at the stage of practical applications. A car navigation system, rocket launching, train routeing, gyrocompass for seeking north and other applications have been tried. An open-loop configuration, which corresponds to rate tyro, is used in the above applications. On the other hand, a closed-loop configuration corresponding to rate integration tYro, which can meet specification for high-grade aircraft navigation, has also been developed. The second type, the resonator fibre-optic gyro; R-FOG, is attractive because the length of the sensing fibre coil can be shortened to be less than 10 m. Noise characterization has been carried out. A fibre-optic ring laser gyro, F-RLG is also promising, in which Brillouin scattering in a fibre resonator produces laser oscillation. This type may have a possibility to provide a quite simple configuration.
Car navigation system using a fibre-optic gyroscope the development of a new navigation system (multi AV system)
Shinya lshikawa Nissan M o t o r Co. 9th Meeting o n Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society o f Applied Physics The new navigation system, the Multi AV system, is available in the 1991 Cedric, Gloria and Cima models. We developed this system, attaching importance to accuracy, operation and safety. A fibre-optic gyroscope was employed in mass-production cars and remarkably improved precise positioning. Furthermore, the new map-matching logic covering all Japan was developed and the database of the map was expanded. Therefore, this system has a great practical use.
9th Meeting on Lightwave Sensing Technology, Japanese Society o f Lightwave Sensing Technology, J a p a n Society of Applied Physics The passive ring resonator fibre-optic gyro (RFOG) using a FM spectroscopy technique is described. RFOG requires not only a highcoherence light source but also a high finesse fibre ring resonator. Therefore, a highly coherent laser diode module (HCLDM) with 100 kHz linewidth has been developed using the optical feedback from a hemispherical reference cavity. A l0 m length fibre ring resonator with finesse 91 has been developed, in which the principal axes of the fibre were rotated by an angle of 90 ° with respect to each other. The FM spectroscopy technique was employed in order that the system could have a higher sensitivity, a wider bandwidth and a lower influence from the IM noise of the LD than the lock-in detection technique. From a signal-to-noise ratio of the demodulated signal, the resolution of the bread board model was estimated to be 0.04 ° hr(the integration time of measurement is 10 s).
Serrodyne fibre-optic gyroscope with high-scale factor performance
Sadaomi Sakuma, Shin-ichi Kawada, Toshiyuki Muroi, Isao Masuzawa, Shigeru Nakamura, Yoshiaki lmamura, Takao Sagawa Tokimec Inc 9th Meeting o n Lightwave Sensing Technology, Japanese Society of Lightwave Sensing Technology, J a p a n Society of Applied Physics This paper describes the prototype serrodyne fibre-optic gyroscope for an attitude and heading reference system. It has an integrated optic chip which incorporates a Y-branch coupler, a polarizer and electrodes for phase modulation, and operates at a wavelength of 830 nm. Closedloop computer simulation and calculation are performed to develop a new technique which markedly reduces the scale-factor error due to the imperfect solodyne-driving wavcform. Current scale factor performance of the gyroscope with a polarization maintaining 150 m sensing coil is presented.
Optics 8t Laser Technology 262
Vol 25 No 4 1993