Abstract: Aiming at providing a new kind of object positioning method,designing a kind of simple operation and easy to implement in engineering coordinate locator with applying the ultrasonic ranging principle to the object plane positioning,which has AT89S52 single chip microcomputer as its core to drive two steering engines MG946R running and two ultrasonic ranging modules US-100 sector scan.The US-100 launches ultrasonic signal and gathering feedback signals in time-sharing.The microcontroller disposing of the feedback signal and calculate the distance measurement.It is communicated with computer by RS-232 serial port and transfer measurement data to computer.The computer uses LabVIEW to display the object's coordinate azimuth and draw its mobile route dynamically in real-time.The experimental result shows that a single ultrasonic transceiver within 4 500mm measurement error between 0~17mm,the measuring blind area for 23mm.The ultrasonic device prototype's functions complete well.

Key words: virtual instrument, ultrasonic ranging, single chip microcomputer, object plane positioning