Design Of Laser Ceilometer Based On FPGA

It is significant to research the cloud which is an important form of atmosphere and atmospheric condition. Cloud prober is an instrument that could be used to measure the cloud character. Currently,most of Cloud probers take the Radar technology as a reference, so that the structure of Cloud prober is very complex and the price is very expensive. According to the theory of pulse ranging method, a high speed signal collecting and processing system which is based on FPGA was designed to construct a system of portable Cloud prober. The portable system also used the small power laser emission and the PIN detectorPortable laser ceilometer system designed by 905nm small power laser emission,firstly,sent high frequency pulse, then the PIN detection circuit received the reflection signal from the aerosol, and then the digital processing system based on Cyclone? FPGA accomplished data collecting, storing and processing which integrated the self-designed ADC control interface and system timing; Lastly, the system calculated the height of the cloud. This design included 905nm laser emission circuit, PIN detection circuit, high speed ADC and processing system based on FPGA. Cyclone? FPGA integrated laser emission control interface, high speed ADC control interface, NIOS II processor, MAX232 and LCD 12864 control interface. Programming C language in the embedded system realized the arithmetic which appled the fast wavelet to get rid of the noise and calculated grey correlation with the database.Experiments show that the design can realize high speed ADC, system integration is high, anti-interference ability is strong; the designed Cloud prober can receive the laser reflection signal; after debugging, the system can measure the height of overcast cloud and the results of the measurement are in good consistency.