The use of physical security technologies are becoming important to prevent intruders from stealing or vandalizing
property, and leaking personal information, as well as to secure personal safety. At many important facilities, fences are
installed along the boundary of the premises to prevent any intrusion. Vibration sensors need to be easily fixed to the
fences even around intricately shaped premises for monitoring a wide range of areas. We have proposed and
implemented a vibration sensor integrated with optical fiber and an optical interference system. To prevent any false or
missing alarms, we have also investigated a signal processing system that can be used to judge whether an alarm is
triggered by a natural phenomenon, small animals, or human intrusion.
Open-loop and closed-loop I-FOG products have been successfully applied to a number of industrial and commercial applications including vehicle navigation systems, auto-guided vehicle, attitude control systems of unmanned agricultural helicopter, pipe-mapping and north-finding systems.
The open-loop I-FOG has been applied to a number of industrial and consumer applications such as vehicle navigation systems, attitude control systems of unmanned agricultural helicopter, pipe-mapping systems, north-finding systems, etc. Its mass production technology is also described.
This paper will present the current status of the fiber optic gyroscope (FOG), a ring interferometric rotation sensor for commercial applications by industries and consumers. An open-loop FOG with all polarization-maintaining fiber components is being used in these applications. One primary application is in vehicle navigation systems for automobiles, and a mass-produced has already been installed in luxury automobiles in Japan. Another application is in sweeper robots, Other applications such as a route-measuring system for boreholes, an attitude-controlling system for industrial helicopters, and an optocompass or north-seeking instrument will also be described. These FOGs are compact and reliable and need only a +12 V or a +24 V DC power source. This bias error is determined by the electrical system rather than the optical system and varies between 0.01 and 36 deg/h depending on the design of the signal-processing unit. The scale factor error varies between 0.1% and 1% also depending on the design, however, it is stable over the temperature range from -30 to 85 degree(s)C.
We have investigated fiber optic gyroscopes that use phase-modulation signal processing for use in automobiles. These gyroscopes use an integrated optical gyrochip and low-cost elliptical-core polarization-maintaining optical fiber. Fiber-to-fiber insertion loss deviation is less than +/- 0.4 dB at a wavelength of 0.83 micrometers over a temperature range of -30 to +80 degree(s)C, while the core dimensions of pigtailed fiber are as small as 4 X 1 micrometers 2. A gyroscope was developed for navigation systems and on board testing is now being performed. A gyroscope for chassis control systems is also being developed.
Fiber optic gyroscopes (FOGs) have been developed for vehicle navigation systems and are used in Toyota Motor Corporation models Mark II, Chaser and Cresta in Japan. Use of FOGs in these systems requires high reliability under a wide range of conditions, especially in a temperature range between -40 and 85 degree(s)C. In addition, a high cost-performance ratio is needed. We have developed optical and electrical systems that are inexpensive and can perform well. They are ready to be mass-produced. FOGs have already been installed in luxury automobiles, and will soon be included in more basic vehicles. We have developed more inexpensive FOGs for this purpose.
An optical gyrocompass is based on the high-performance fiber optic gyroscope's sensitivity to the earth's rotation rate. The advantage over conventional gyrocompasses is that it starts up quickly and should also have a long operating life. An optical gyrocompass is developed with a north-seeking accuracy of 0.05 degree.
Fiber optic gyroscopes (FOGs) are developed for industrial and consumer applications. The bias error, which is determined by electrical circuits rather than the optical system, varies between 0.01 and 36 deg/hr depending on the construction of the electrical system. The scale factor error at each input rate is less than 0.5% in the temperature range of -30 to 85 degree(s)C. These FOGs are compact, highly reliable, and need only a +12 V D.C. power source. They are ready for mass production.
KEYWORDS: Gyroscopes, Signal processing, Modulation, Electronics, Phase shifts, Phase shift keying, Optical fibers, Digital signal processing, Detection theory, Signal detection
Open-loop signal processing techniques for a phase-modulated optical fiber gyroscope are discussed and classified according to sampling or non-sampling, frequency- or time-domain, and real or equivalent time schemes. A duality theory between frequency and time for the gyroscope signal is developed. The rotation rate supplied to the gyroscope is detected from both the frequency and time signals. As examples of equivalent time signal processing, down sampling and pulse modulation techniques are proposed.
FOGs are developed for industrial applications such as car navigation or location systems, self-guided robots, bore-hole route survey systems, geodesic compasses, etc. The FOGs are based on an open loop and minimum reciprocal configuration with all polarization maintaining (PM) fiber components. Because the fiber optic components are almost ready for mass production, FOGs provide an attractive economical aspect.
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