The System Of Ultrasonic Ranging Base On FPGA

As an indirect distance measurement,the system of ultrasonic ranging has been widely used in traffic obstacle avoidance,safety early warning,auto-navigation and field robot for its good capability and lower price.But ultrasonic distance measurement also has much limitation in special actual application.The research on improving the measurement accuracy is very important to developing the technology of ultrasonic ranging.In market,most of the systems of ultrasonic ranging use the single chip microcomputer as a main controller to transmit the driving signal.The measurement accuracy cannot win great satisfaction,although it's cheap.The FPGA(Field Programmable Gate Arrays) is a kind of programmable device.It provides a new plan of design for the system of ultrasonic ranging.As these reasons,this paper introduces a system of ultrasonic ranging base on FPGA.The most important parts of the system are the signal transport and receiver. There is a error of time delay When the program is running.For this reason the MCU can not match the needed of exactitude ranging.This paper introduces the hardware of the system.With a view to the software of the system,the FPGA can easily control the center frequency of ultrasonic detector by dividing the frequency of the main clock.It can get an accuracy time of the measurement through a frequency counter.As a conclusion,the design can improve the accuracy of the system.