Differential Absorption Laser Radar System Performance Analysis And Information Processing System Simulation

CO2 laser-based differential absorption lidar(DIAL) systems have been used extensively for the remote sensing measurement of molecular species in the atmosphere and trace gases, therefore, have important value in military and civilian fields.For the needs of researching a useful DIAL system, in this thesis, we studied a vast Chinese and English literature and discussed the principle of DIAL system in detail. We analyzed the factor of influencing the accuracy and sensitivity of measurements, in special, discussed the influence of atmospheric turbulence and laser speckle. Under our task experimental condition, we calculated the sensitivity of our planning to develop DIAL system with direct detection, besides, we studied the relationship between the sensitivity of measurement and atmospheric refractive-index structure constant and applied Matlab program simulated the system parameters such as beam diameter, laser divergence angle, detection distance and gained relevant relationship curves. It is useful for selecting reasonable system parameters through it.For the data process in DIAL system, we discussed the combined effects of temporal autocorrelation and lasers cross correlation and signal averaging. If signal averaging technology was used in our CO2 DIAL system, then would improved the sensitivity of measurement clearly and could meet the demand of development. Moreover, this thesis simulate the part of signal processing in DIAL system and validate the feasibility of our signal processing methods.Because all of this research began in the front of task, the results just based on the experimental data of abroad literature, so, this is a theoretically research.