| Summary: | 碩士 === 清雲科技大學 === 資訊工程所 === 100 === A novel positioning system is introduced in this thesis. With the help of the system the blind can get early warning of where the obstacle is. The system has three ultrasonic sensors and an ultrasonic emitter. Three sensors are located at different apex of an isosceles triangle and an ultrasonic emitter is located at center of the triangle base. With the circuits of emitter and the sensors, obstacles in front of the blind can be detected by using time-of-flight of the ultrasonic wave. Because of amplitude recession, temperature, and humidity can influence the measurement accuracy, a cone with angle of ±30°, 1 meter to 2 meters in front of the blind has been evaluated as a test region for the system. A lot of presetting coordinates are used as location candidates for the obstacle. We found that only little calculations are needed to decide which presetting coordinate can be selected as location of the obstacle by using time differences measured from the sensors. We believe the positioning algorithm developed in this thesis will make an embedded blind guiding system to be realized easier. Finally, some simulation results and conclusions are also given in this thesis.
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