| 摘要 |
PROBLEM TO BE SOLVED: To provide a position identification system which grasps the position of a movable body even without providing a landmark such as a tag with position information written thereon on a road surface of a traveling lane. SOLUTION: An ultrasonic wave is transmitted outward by a transmitter 1 and the frequency of the ultrasonic wave is increased in proportion to time. The ultrasonic wave transmitted from the transmitter 1 is reflected by surrounding obstacles and received by a receiver 2. A mixer 3 mixes this reflected wave and the then ultrasonic wave of the transmitter 1 with each other to generate a beat. An output of the mixer 3 goes through a lowpass filter 4 and an A/D converter 5, and is converted into a frequency spectrum in a high-speed Fourier transformation part 6. A correlative value calculation part 7 calculates a correlative value between a reference frequency spectrum previously stored in a storage part 9 and a present frequency spectrum inputted from the transform part 6 while a position determination part 8 determines the position of the movable body M, based on the correlative value. COPYRIGHT: (C)2008,JPO&INPIT
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