Сomparative Analysis of Sounding Range for Aerosol Lidar Alternate Designs

The aerosol lidars intended for expeditious monitoring of the atmosphere allow us to define remotely characteristics of atmospheric aerosol and cloudy formations in the atmosphere. When designing the laser systems, one of the first tasks to be solved is to determine a potential range of laser system operation. The laser system operation range depends on the algorithm for processing laser signals used in laser system. It can be estimated from an equality condition (for the limit range) between the power characteristics of the useful laser signal (coming to the receiver) and the threshold power characteristics of the laser system receiver. Today, practically, all the existing aerosol lidars operate with rather low repetition rate and with rather powerful single pulses. An alternative to it is operation with high repetition rate and with a low power of single pulses. The paper presents comparative analysis of a sounding range for the Aerosol Lidar in UF (0.355 microns), visible (0.532 microns) and near infrared (1.064 microns) spectral ranges for various lidar options (with different repetition rates of laser pulses and different algorithms to process laser locational signals). To estimate the limit sounding ranges L three different algorithms were used: - equality of useful signal power and threshold power of the receiver; equality of useful signal power in the no-accumulation mode and minimum detected (threshold) power in the no-accumulation mode; equality of useful signal power in the accumulation mode and minimum detected (threshold) power in the accumulation mode. Results of mathematical modelling show that the signals accumulation mode provides significantly longer sounding range, than the signals no-accumulation mode. The limit sounding range in the mode of signals accumulation is defined by dependence of the laser pulse power on the repetition rate