A kind of fiber optical temperature variety sensor based on fiber optical ring resonator is presented. The temperature variety causes the variety of the round-trip phase of the ring and the movement of the resonance d...
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ISBN:
(纸本)081945589X
A kind of fiber optical temperature variety sensor based on fiber optical ring resonator is presented. The temperature variety causes the variety of the round-trip phase of the ring and the movement of the resonance dips. The magnitude and rate of the movement are proportional to the magnitude and rate of temperature variety, respectively. Through the measurement of the dips movement, the temperature variety can be sensed. In this paper, we make a theoretic analysis about the sensor, propose the system configuration, present a simple and effective signal detection method, and analyze the performance of the sensor. This kind of temperature sensor has such characteristics as high sensitivity, simple detection method, flexibly changeable sensitivity for different applications and temperature variety detection. Combined with the multiplex technology such as time division multiplexing (TDM), the sensor can form temperature variety sensor array for distributed fiber optic temperature detection.
Non-gyro inertial measurement unit (NGIMU) uses only accelerometers replacing gyroscopes to compute the motion of a moving body. Use the traditional accelerometer configurations for reference, a novel nine-acceleromet...
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ISBN:
(纸本)081945589X
Non-gyro inertial measurement unit (NGIMU) uses only accelerometers replacing gyroscopes to compute the motion of a moving body. Use the traditional accelerometer configurations for reference, a novel nine-accelerometer configuration of NGIMU is proposed with its mathematic model constructed. This configuration can acquire the expressions of the angular accelerations directly and avoid calculating the differential poly-equation. To confirm the effectiveness of the design, the experiment system is set up and the DSP data processing circuit is also done. In addition, the experiments of the angle estimating are performed and the results show that the design can reflect the trend of the angle changing with high precision to some extend.
A novel wide dynamic range (WDR) snapshot active pixel sensor for ultra-low power applications is presented. The proposed imager allows capturing of fast moving objects in the field of view and provides WDR by applyin...
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A novel wide dynamic range (WDR) snapshot active pixel sensor for ultra-low power applications is presented. The proposed imager allows capturing of fast moving objects in the field of view and provides WDR by applying adaptive exposure time to each pixel, according to the local illumination intensity level. Driven by low-power dissipation requirements, the proposed pixel is operated by dual low voltage supplies (1.2 and 1.8 V) and utilizes an advanced low-power sensor design methodology. A test chip of a 32 * 32 array has been implemented in a standard 0.35-um CMOS technology. A single pixel occupies 18 * 32 mu m area and is expected to dissipate 18.5 nW at video rate. System architecture and operation are discussed and simulation results are presented.
A novel tilt measurement method is proposed based on self-demodulated fiber Bragg grating (FBG) sensor system, which consists of a couple of matched FBGs and a cantilever-based pendulum clinometer. With a cantilever s...
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A novel tilt measurement method is proposed based on self-demodulated fiber Bragg grating (FBG) sensor system, which consists of a couple of matched FBGs and a cantilever-based pendulum clinometer. With a cantilever structure, the tilt angle is measured by means of a differential form of Bragg wavelength shifting, with which the cross-sensitivity of temperature is eliminated simultaneously. It has been proved by both simulations and preliminary experimental results that a high resolution better than 0.0022° can be achieved in the range of ±10°.
Optical fiber sensors have received increasing attention in the fields of aeronautic and civil engineering for their superior ability of explosion proof, immunity to electromagnetic interference and high accuracy, esp...
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Optical fiber sensors have received increasing attention in the fields of aeronautic and civil engineering for their superior ability of explosion proof, immunity to electromagnetic interference and high accuracy, especially fitting for measurement applications in harsh environment. In this paper, a novel FBG (fiber Bragg grating) strain sensor, which was packaged in a 1.2mm stainless steel tube by epoxy resin, was developed. Experiments were conducted on the universal material testing machine to calibrate its strain transferring characteristics. The sensor has the advantages of small size, high precision and flexible use, and demonstrates promising potentials. Ten of tube-packaged strain FBG sensors were applied in the vibration experiment of submarine pipeline model. The strain measured by FBG sensor agrees well with the electric resistance strain sensor.
The dispersion properties of the reflection-induced retardance of the polarization- preserving reflecting medium layer and its effect upon the sensitivity of an optical current sensor are theoretically analyzed taking...
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The dispersion properties of the reflection-induced retardance of the polarization- preserving reflecting medium layer and its effect upon the sensitivity of an optical current sensor are theoretically analyzed taking the Jones' Matrix as a mathematical tool and simulated with a computer. The investigation results show that the dispersion will obviously affect the scale factor of the system. Therefore, it is necessary to stabilize the driving current and the ambient temperature of the optical source by some technical means. These results might be useful for the researchers and designers working in the optical current sensing techniques area.
A new laser ultrasonic sensor for testing samples' thickness is developed. This sensor has high-frequency response and high sensitivity. Furthermore it is easy to adjust. When the sensor is used to focus on polish...
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A new laser ultrasonic sensor for testing samples' thickness is developed. This sensor has high-frequency response and high sensitivity. Furthermore it is easy to adjust. When the sensor is used to focus on polished iron plate, well-defined longitude-wave and its echo waves can be obtained. Based on the experimental results, the sample's thickness can be deduced. The theoretical and experimental results are in good agreement with relative error of 0.5%.
Recently, fiber-optic current sensor technology has reached a degree of maturity to compete with conventional instrument transformers. However, it has not been commercialized until quite recently because of a few inst...
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Recently, fiber-optic current sensor technology has reached a degree of maturity to compete with conventional instrument transformers. However, it has not been commercialized until quite recently because of a few instability issues, such as linear birefringence effect in the fiber-optic sensor coil and intensity noises caused by optical light sources and components. In this paper, we report on research efforts we performed to address these issues. Firstly we used different optical sources, such as an ASE source, a F-P multimode LD, and a DFB singlemode LD, to compare the effects by the light sources. Also we used different optical fibers, such as flint glass fiber, with different reflection mirrors. From the experimental results, we obtained output variation down to 1% in the presence of mechanical disturbances and the broadband source showed the best noise characteristics about 13-23 dB better than LDs. The details of the experiments with other design parameters are also presented.
In order to increase the number of channels available to a grating based strain sensor system specialised gratings were designed that would allow the sensor system to be able to distinguish between a number of grating...
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In order to increase the number of channels available to a grating based strain sensor system specialised gratings were designed that would allow the sensor system to be able to distinguish between a number of gratings located in the one WDM channel independently of the amount by which they overlap each other in the wavelength domain. Distinguishing between gratings is achieved by inscribing a carrier frequency in the grating spectrum, so that each grating can be addressed in the Fourier domain via the spectral information centred around the inscribed carrier frequency. Tests performed on the gratings successfully show the ability to distinguish between three spectrally overlapping gratings. The calculated value for Young's modulus, 72±3GPa, was found to be in keeping with the standard value of 70.3GPa for fused silica.
Recon/Optical, Inc. (ROI) is developing an advanced airborne Intelligence, Surveillance, and Reconnaissance (ISR) demonstration system based upon the proven ROI technology used in the SHAred Reconnaissance Pod (SHARP)...
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ISBN:
(纸本)0819457728
Recon/Optical, Inc. (ROI) is developing an advanced airborne Intelligence, Surveillance, and Reconnaissance (ISR) demonstration system based upon the proven ROI technology used in the SHAred Reconnaissance Pod (SHARP) for the U.S. Navy F/A-18. The demonstration system, which includes several state-of-the-art technology enhancements for next-generation ISR, is scheduled for flight testing in the summer of 2005. The demonstration system contains a variant of the SHARP medium altitude CA-270 camera, comprising an inertially stabilized Visible/NIR 5Kx5K imager and MWIR 2Kx2K imager to provide simultaneous high resolution/wide area coverage dual-band operation. The imager has been upgraded to incorporate a LN-100G GPS/INS within the sensor passive isolation loop to improve the accuracy of the NITF image metadata. The Image Processor is also based upon the SHARP configuration, but the demo system contains several enhancements including increased image processing horsepower, Ethernet-based Command & Control, next-generation JPEG2000 image compression, JPEG2000 Interactive Protocol (JPEP) network data server/client architecture, bi-directional RF datalink, advanced image dissemination/exploitation, and optical Fibrechannel 1/0 to the solid state recorder. This paper describes the ISR demonstration system and identifies the new network centric CONOPS made possible by the technology enhancements.
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