Geoscience Reference
In-Depth Information
Auto Alignment
Mechanism
Mirror Controller
Laser Head
Telescope
Laser Driver
38 deg.
PMT
Scaler
Horizontal Scanning
Mechanism
Rotation stage
Controller
Window
Rotation Stage
Fig. 1. System configuration of portable automated lidar.
Table 1. Specification of PAL.
Laser
LD pumped Nd:YAG Laser
Pulse power 15
µ
J
Wavelength 532 nm
Detector
Photo-multiplier (photon counting mode)
Telescope
Schmidt-Cassegrain
Aperture 20 cm diameter
Field of View 0.2mrad
Scaler
Resolution 24 m
Range 24m
Averaging 10 or 20 s
accumulated by a scaler (Stanford Research Systems SR430). The spatial
resolution is 24 m and the maximum observation range is 24 km (altitude
15 km). The observation is made though the vertical window of the
laboratory, leading to the capability of measurement under all weather
conditions. The observation data have been accumulated since the year
2004. The system status can be checked and the data can be downloaded
through the Internet.
A built-in rotation stage for horizontal scanning has recently been
installed. As the PAL system is fabricated as a monolithic structure
including a laser head and a detector, the rotation stage was “inserted”
under all the optical systems. The scanning observation of a range
of
25 degrees is conducted every hour, interrupting the continuous
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