Tatsuya Kumagai

Commercial applications of mass-produced fiber optic gyros

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.

Development of an optical gyrocompass using a high-sensitivity fiber optic gyroscope

An optical gyrocompass is based on the high-performance fiber optic gyroscopes sensitivity to the earths 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 for vehicle navigation systems

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.

Development of open-loop fiber optic gyroscopes for industrial and consumer use

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.

Fiber optic gyro productization at Hitachi (Invited Paper)

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.

Fiber-optic vibration sensor for physical security system

Physical security technology is increasingly being used to prevent intruders from stealing or vandalizing property, leaking personal information, and threatening personal safety. Fences have been installed along the boundary of the premises of many public facilities to prevent any intrusion, and vibration sensors need to be easily fixable to these fences including around intricately shaped premises in order to adequately monitor a range of areas. Previously developed fiber-optic gyroscopes (FOGs), rotation sensors, and fiber-optic distributed temperature sensors (DTSs) are now used in various industrial systems, and if such well-established technologies can be applied to vibration measurement, it is reasonable to expect stable characteristics and reliability under severe environmental conditions such as the physical security and health-monitoring of a structure. A Sagnac interference system of FOG and an optical time domain reflectometer (OTDR) function of DTS have been investigated for their potential application to vibration sensing. The detection of vibrating position was also investigated for each type of sensor.

Glucose sensor with a Sagnac interference optical system.

The angle of optical rotation was measured by detecting the phase difference between clockwise and counterclockwise circular polarized light that propagated in a sensing loop. This polarimeter, or glucose sensor, consisted of a Sagnac interference optical system with a polarization-maintaining optical fiber, so it was not affected by the control limitations of the polarization rotation angle or the optical power fluctuation that occurs with scattered light, reflection, or polarization rotation in an optical system. The angle of rotation was measured from the phase difference of the glucose sensor when the concentration of glucose was changed. We confirmed that the resolution of optical rotation was 5×10(-4)  deg, and the resolution of the glucose concentration was 1  mg/dl accordingly. The measured specific rotation of glucose was mostly equal to a physical property value. One applications of this glucose sensor is in measuring the blood sugar levels of diabetic patients.

Optical Intrusion Detection Sensor with Polarization Maintaining Fiber

An optical intrusion‐detection sensor based on a Sagnac interferometer has been developed for fence‐mounted perimeter security applications. The interferometer is completely made of polarization maintaining fiber and related components. This sensor has been adopted by some important institutions as part of their physical security systems.

FIBER-OPTIC GYROSCOPES FOR AUTOMOTIVE APPLICATIONS

We review recent developments in interferometric fiber-optic gyroscopes for automotive applications. These gyroscopes use only elliptical-jacket or elliptical-core polarization-maintaining fibers to make their optical systems immune to environmental effects, and all of them use open-loop phase-modulation signal processing circuitry. We have begun mass-production of a gyroscope for automotive navigation and location systems. Another gyroscope employing an application specific integrated circuit developed for reducing size, cost and power consumption outputs the rotation rate as an analog voltage, and can be used for automotive chassis control and navigation systems. A more accurate gyroscope and a three-axis FOG system combined with clinometers can be applied to motion measurement systems for chassis development and testing. For further enhancement in terms of size, cost, and accuracy, we have developed an integrated optical circuit and a gyroscope that uses it.

Development of fiber optic gyroscopes for industrial and consumer applications

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.