Principle
LEOSPHERE‘s EZ Lidar ™ is a ground-based optical remote sensing
instrument designed to determine the vertical and horizontal properties
of the atmosphere as cloud and aerosol structures. A nanosecond laser
pulse is emitted into the atmosphere where it encounters atmospheric
particles and molecules along the line of sight. A part of this
radiation is scattered backward and collected onto the LIDAR reception
system constituted of an opto-electronic device. The electrical signal
is digitalized and recorded by a computer for real time or postponed
processing.
Detection/ Acquisition
Emission and detection are parallel. A stable alignment is ensured thanks
to an exclusive optical design (CEA-CNRS 04/50115, BD1527-22/01/04 patent). The
alignment robustness has been tested during several airborne missions, in order
to experiment it in tough conditions.
OVERLAP FUNCTION
Unlike many Lidar systems that are totally or partially blind in the first hundred meters or first kilometres of observation range, full vision is reached at 200m for the ALS300 and 500 m for the ALS450.
BACKGROUND SIGNAL
The LIDAR efficiency is highly dependent on the background radiation due to natural or other sources of light. Collecting the “right photon” among a tremendous amount of light is not easy. It induces a large difference in the performances of most of the remote-sensing systems during daylight. LEOSPHERE’s engineers managed to solve this problem by applying a spatial filtering method that reduces the background signal down to 1%. As a result, EZ LIDAR gets higher performance during daytime than traditional lidar system
OVERLAP FUNCTION
Unlike many Lidar systems that are totally or partially blind in the first hundred meters or first kilometres of observation range, full vision is reached at 200m for the ALS300 and 500 m for the ALS450.
BACKGROUND SIGNAL
The LIDAR efficiency is highly dependent on the background radiation due to natural or other sources of light. Collecting the “right photon” among a tremendous amount of light is not easy. It induces a large difference in the performances of most of the remote-sensing systems during daylight. LEOSPHERE’s engineers managed to solve this problem by applying a spatial filtering method that reduces the background signal down to 1%. As a result, EZ LIDAR gets higher performance during daytime than traditional lidar system
Ouput Data
EZ Lidar systems provide in real time both qualitative and quantitative information of the atmosphere:
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OUTPUT DATA |
- Atmospheric backscatter light intensity (raw data) |
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- Solid angle and background calibrated data |
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- Vertical backscatter and extinction profile |
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- Vertical Aerosol profile |
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- Planetary Boundary Layer and residual layer heights |
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- Semi-transparent cloud height and top |
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- Optical depth integrated over whole Lidar range |
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- Dynamic structure of the atmosphere (e.g gravity waves...) |
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- Asphericity information on the particle in order to discriminate some particles from others (soil dust from other aerosol, ice/water phase of the clouds…) |