Multilayers Clouds Monitoring By Micro-Joule Lidar Based On Photon Counting Receiver And Diode Laser

Multilayers clouds layer's horizons have been detected in strong snowing condition by using the micro-Joule eye-safe lidar. Lidar is based on the 1 mu J (30 ns length) pulsed diode laser, which operates with high repetition rate (up to 10 kHz) and silica (Si) photon counting receiver (Single Photon Avalanche Diode, SPAD) from Czech Technical University. Note that the unique low avalanche voltage of Czech SPAD (similar to 26-28 Volts), low power consumption (similar to 0.2 Watts), the wide (-100 to 20 degrees C) temperature operation and low weight (similar to 0.94 kg) were the main arguments to involve this lidar version into the NASA Mars Polar Lander mission a decade ago in 1999. The Geiger (photon counting) mode of SPAD operation and laser high repetition rate allow us to apply the specifically statistical approach to the development of the remote sensing return, which is scattered by aerosol and other inhomogeneous along the sounding trace. To get of reliable signal-to-noise ratio (SNR) we have to use a few hundred or thousand laser pulses because the probability of the photon scattered by sounding object is smaller than unit. As a role a Poison statistics is used to development of the remote sensing return.