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Signal Extraction And Simulation For 2μm Coherent Wind Lidar

Posted on:2008-08-24Degree:MasterType:Thesis
Country:ChinaCandidate:J ZhangFull Text:PDF
GTID:2178360245496763Subject:Physical Electronics
Abstract/Summary:PDF Full Text Request
Based on the measurement of the scattering of aerosol in atmosphere, using monostatic antenna, heterodyne detection, coherent wind lidar can obtain Doppler frequency signals directly from backscatter of aerosol, and then via the data retrieval operations, 2-dimensional or 3-dimensional atmospheric wind fields can be obtained. This is the most effective method which researches the small and mean scale weather.In this paper, the method of wind lidar backscatter signals detect is mainly researched, then carried on the numerical simulation and in hardware in the loop simulation. The time-frequency character of coherent wind lidar backscatter signal is analyzed in theory, namely, with a large of clutter and noise follow with the object signal, the SNR is very low. So how to detect the lidar backscatter signals in the low SNR situation, detect wind lidar backscatter signals and frequency spectrum, prove the theory by the simulation experiment.First in the paper, the theory elements of coherent Doppler lidar are briefly summarized. The principle of coherent Doppler lidar, lidar backscatter detects method, which are the pulses integration technology and match filter technology, are introduced primarily.Then, the statistical character of lidar signal, clutter and noise are researched, create the object signal and the detect background noise by simulating, this is the lidar backscatter signal. Based on the above research, the lidar pulses integration is simulated, including the coherent integration and non-coherent integration. The result of simulation shows the pulses integration technology can effective improve the lidar backscatter signals SNR. According to the technology of coherent wind lidar, 75 pulses are integrated, the SNR improve 20dB.Again, the match filter technology is researched, the coherent pulses apply the technology by simulation, and then the narrowband Doppler match filter array is applied to the coherent wind lidar.. Finally in the chapter, the Doppler lidar backscatter signal information detect system is simulated, detect object information that is the speed of 10m/s, distance the lidar 6Km. The simulation result is particular analyzed and discussed, which shows all the arithmetic about the Doppler lidar backscatter signal detect are feasible.Finally, in view of the coherent wind lidar signal processing overall demand ,discuss and design the lidar data acquire system hardware, and develop the software of data acquire system, and then carried on the simulation test, acquire the laser mean frequency after heterodyne detection succeed.
Keywords/Search Tags:coherent wind lidar, signal processing, pulses accumulate, match filter
PDF Full Text Request
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