| Acoustic detection technology has been widely applied in the underwater acoustics,aerospace, automotive, nuclear, medical and oil/gas industries. In the past few decades, along with the development of ultrasonic transducer array technology, the range of the acoustic detection technology application in air is increasing rapidly.This article explores the ultrasonic phased location system which is composed by two parts: ARM9 (S3C2440) microprocessor as the upper computer and FPGA as the lower computer. The system takes advantage of the bistatic ultrasonic transducer array whose transmitting array and receiving array are different in number of array elements and inter-element spacing. In this way, not only the main lobe becomes narrow but also grating lobe is suppressed. The function of the system is the detection and the location of multiple targets in the front certain angle range, in addition, calculation and the display of the position information about all the detected targets.Firstly, the article complete the design of the hardware circuit which includes an ultrasonic transducer’s transmitting circuit , receiving circuit and A/D acquisition circuit.Secondly, The article designs man-machine interface by Visual C# language. The upper computer software is explored on Windows CE.NET embedded operating system. Upper computer is display and control terminal, its main function is accomplishing asynchronous serial communication, data storage , Fast Convergence of Energy Center, rectangular mobile carrier control and target azimuth information display. Finally, the article designs the lower computer software by VHDL language. Lower computer is the core of the whole system, and its main function is accomplishing asynchronous serial communication, Phase-controlled Transmission, PGA controller, A/D sampling controller, beamforming and SDRAM controller.Experiments shows that, each part of the system is able to reach the design requirements,particularly the ultrasonic transducer arrays. |
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