Designation And Implementation Of Fiber Optical Sensor Detecting Algorithm On The DSP Platform

The sensor is a physical device or a biological organ, capable of detecting or feeling the external signals, physical conditions (such as light, heat, humidity) and chemical composition (such as smoke), and then sending the detected information to another device or organ.The development direction of sensor has been towards the direction of sensitivity, accuracy, adaptability, compactness and intelligence. In this process, a new member of acclaimed in the sensor family, is the fiber optical sensors. Optical fiber has many excellent properties, such as:anti-electromagnetic interference and atomic radiation. Also it has many good mechanical properties (such as thin diameter, soft, light weight) and chemical properties, such as insulated, non-induced electrical properties, water-resistant, high temperature tolerance, corrosion-resistant. It can reach the place which people can not reached, such as high temperature zone, nuclear radiation zone etc. It can play a role as people's eyes and ears, receiving the information which people can not feel.The principle of distributed fiber optical sensing system is that the optical fiber is used as a sensing element and transmitting medium simultaneously. A fiber optical sensing system can detect the temperature and strain changes along the optical fiber by using the OTDR (Optical Time Domain Reflectometer) technology. The principle of temperature measurement is based on Raman Scattering Effects of a distributed temperature sensing system. The principle of strain measurement is based on Brillouin Scattering Effects of a distributed temperature and strain sensing system which can measure both temperature and strain simultaneously.A fiber optical sensing system is composed of five parts, including optical signals' transmitting and receiving, data capture card, DSP signals'processing module, GUI, and sensing optical fibers. The paper is focused on the sampled data's processing on the DSP platform. The procedure includes 2 parts:one is the signals' pattern recognition; the other is the location calculation. The system can calculate the position where the disturbance is happening and alarm by mean of the correlation calculation.The architecture of this paper is as follows. The chapter 1 introduced the fiber optical sensor. The chapter 2 illustrated the principle and algorithm of fiber optical sensing system. The chapter 3 described the DSP software and hardware platform and the method for verifying the usability of hardware platform. The chapter 4 presented the software part of the project, including the implementation of every module, the optimization of program and comparison between the DSP platform and PC platform's performance results. At last, the chapter 5 summarized the whole paper's content.