The angular velocity data of Fiber-Optic Gyro (FOG) has been analyzed to locate the singularity by the wavelet transform (WT) method. By using WT analysis method to decompose and reconstruct the signal of pavement data collecting by the FOG, the different types of pavement singularities can be extracted. The experiments are conducted on different road surfaces. The experimental results show that the locations of bumps and expansion joints have been obtained, with a relative precision of 0.5 m and an absolute precision of 2 m over 2.4 km. The characteristic of the pavement roughness can also be identified.
FBG-based perimeter security is a new security method. It can be distributed security and intelligent addressing. So far, it has been widely used in a variety of security. During the idle time of fiber Bragg grating (FBG) perimeter security defense system, the available FBG perimeter sensor can be utilized as temperature sensor, frequency sensor and acceleration sensor according to its characteristics. The sensor can collect more real-time environment information that make the defense system functions more perfect and more powerful. All of this information can help us to understand the changes in the environment and avoid some accidents.
With the development of the society and economy and the improvement of living standards, people need more and more
pressing security. Perimeter security alarm system is widely regarded as the first line of defense. A highly sensitive Fiber
Bragg grating (FBG) vibration sensor based on the theory of the string vibration, combined with neural network adaptive
dynamic programming algorithm for the perimeter security alarm system make the detection intelligently. Intelligent
information processing unit identify the true cause of the vibration of the invasion or the natural environment by
analyzing the frequency of vibration signals, energy, amplitude and duration. Compared with traditional perimeter
security alarm systems, such as infrared perimeter security system and electric fence system, FBG perimeter security
alarm system takes outdoor passive structures, free of electromagnetic interference, transmission distance through
optical fiber can be as long as 20 km It is able to detect the location of event within short period of time (high-speed
response, less than 3 second).This system can locate the fiber cable's breaking sites and alarm automatically if the cable
were be cut. And the system can prevent effectively the false alarm from small animals, birds, strong wind, scattering
things, snowfalls and vibration of sensor line itself. It can also be integrated into other security systems. This system can
be widely used in variety fields such as military bases, nuclear sites, airports, warehouses, prisons, residence community
etc. It will be a new force of perimeter security technology.
To accelerate the usage of traditional optical fiber micro- bend sensor in the distribution detecting of actual smart structures, a novel micro-bend sensor structure is developed. Experiments manifest that it has good sensitivity, repeatability. In addition, based on different conditions and monitoring demands of smart structure, this sensor structure can consist of a series of sensors with different sensitivity, initial dissipation of light intensity and tensile strength by altering some structural parameters.
This paper presents a kind of low cost, one-off fiber optic temperature sensor that has been used to replace the expensive Pt-Rh thermocouple to measure the temperature of molten steel. The detail design scheme of the probe of the fiber optic sensor, the structure of the secondary instrument and the calculating method has been studied.
In this article, the conducting schemes for fiber optic gyro (FOG) used int he fast detecting of the smoothness of rail track has been proposed from the practical use point of view. The relevant approximate method of calculating has been given. The experiments in lab have been carried out, and the factors to influence the detecting precision of the smoothness of rail track such as the precision of FOG have been analyzed.
A practical fiber optic transmitting system of analog sensing signal has been introduced. This system has the advantages of high transmitting precision, immunity from disturbance, long transmitting distance and low cost.
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