LASER SYSTEMS Ltd.
1-st Krasnoarmeyskaya 1, St. Petersburg, 198005, Russia
Fax: 07+(812) 251-22-57
e-mail: office@iltt.ru
1.
Purpose
The
lidar system is intended for ecological monitoring of the atmosphere, for
operative remote determination of the physical and chemical composition of
atmospheric pollutants over the megapolices, large industrial centers, regions
of the ecological emergencies or hostilities with a probability of toxic agents
application.
2.
Brief description
The
lidar system represents a transportable modular where the laser emitters, transmitting-receiving channel, data acquisition and
control system and other parts are deployed.
The
system consists of two visible-ultraviolet direct detection lidars and two
coherent detection infrared ones. Each pair allows the DIAL technique.
The
system is equipped with two Nd:YAG frequency doubled lasers, two tunable
Ti:sapphire frequency doubled and tripled lasers and two tunable TEA CO2
lasers (with two additional CW CO2 injection lasers and two CW CO2
frequency stabilized heterodynes), it possesses three independent receiving
channels – 230-532 nm, 750-1064 nm and 9-11 mcm that allows to determine:
·
Location and spatial evolution of the natural and
artificial aerosol objects in the atmosphere (aerosol lidar)
·
Their physical structure (liquid drops, solid
crystalline particles) (polarization multiwave lidar)
·
Numerical density of the atmospheric pollutants
whose absorption lines coincide to the emitting lasers spectral range (DIAL)
The lidar system is a fully autonomous
one including a power source and climate control. It is possible arrangement of
the lidar system on the basis of different trailers or trucks in the special
body-container. The sizes and configuration of the complex can be changed under
particular conditions of work.
3.
Main technical characteristics
|
¹ |
Description |
Value |
|
1 |
General: |
|
|
1.1. |
Minimal
detection range |
0.5 km |
|
1.2. |
Maximal detection range without using of
topographic targets)* |
|
|
1.2.1 |
For
aerosol channel |
15 km |
|
1.2.2 |
For IR
channel |
15 km |
|
1.2.3 |
For UV
channel |
1,5)** – 3 km)*** |
|
1.3 |
Maximal detection
range with using of the topographic targets)* |
|
|
1.3.1 |
For
aerosol channel |
30 km |
|
1.3.2 |
For IR
channel |
30 km |
|
|
For UV
channel |
3)** – 6 km)*** |
|
1.4 |
Aerosol
droplets size (for aerosol channel) |
0.5 – 10 mcm |
|
1.5 |
Species
under test |
|
|
|
For CO2 DIAL channel |
hydrocarbons, freons, organophosphates and others |
|
|
For
Sph:Ti DIAL channel |
SO2,
NO2 |
|
1.6. |
Beam elevation)**** |
±150 |
|
1.7. |
Beam
azimuth)**** |
0 ¸ 3600 |
|
1.8. |
Angle resolution |
3
arc. minutes |
|
1.9. |
Dimensions (maximal) |
7x2.5x2.5
m3 |
|
1.10. |
Weight (maximal) |
8000
kg |
|
1.11 |
Working temperature range |
-200 +450 C |
|
1.12 |
Impact
and vibrations stability |
6g – impact, 5g – periodic (5-50Hz) |
|
2. |
Transmitting unit
characteristics. |
|
|
2.1. |
TEA CO2 laser (2 pcs) |
|
|
2.1.1. |
Output energy
(10P20) Output energy
(P,R 14 –26) Output energy
(others) |
0.5 Joules 0.3 – 0.4 Joules 0.1 – 0.3 Joules |
|
2.1.2. |
Wavelength range (not less than 60 lines of CO2
VR spectrum) |
9
–11 microns |
|
2.1.3. |
Angular divergence |
1.4 mrad (after collimation 0.2 mrad) |
|
2.1.4. |
Beam size |
27 x 27 mm (after collimation 195x195 mm) |
|
2.1.5. |
Pulse duration, (peak and “tail”) |
100
ns and 1 ms |
|
2.1.6. |
Pulse repetition frequency |
10
Hz |
|
2.1.7 |
Refilling interval |
6 months (at the operation time 8 hours per a day) |
|
2.2. |
Titanium: Sapphire
laser (2 pcs) |
|
|
2.2.1. |
Wavelength range |
700 – 950 nm 350 – 480 nm 230 – 310 nm |
|
2.2.2 |
Bandwidth |
0,
05 nm |
|
2.2.3. |
Output energy |
200mJ l=900nm 25mJ l=450nm 6 mJ l=300nm |
|
2.2.3. |
Angular divergence (without beam expander) |
5
mrad |
|
2.2.4. |
Pulse duration |
30
ns |
|
2.2.5. |
Pulse repetition frequency |
10
Hz |
|
2.3. |
Nd-YAG laser (2 pcs) |
|
|
2.3.1. |
Output energy (l=1064nm, 532 nm) |
1000mJ,
300mJ |
|
2.3.2. |
Wavelengths |
532
nm, 1064 nm |
|
2.3.3. |
Angular divergence (without beam expander) |
5
mrad |
|
2.3.4. |
Pulse duration |
30
ns |
|
2.3.5. |
Pulse repetition frequency |
10
Hz |
|
2.4 |
CW
CO2 laser (2 pcs) (local oscillator and injection) |
|
|
2.4.1. |
Power |
2
W |
|
2.4.2. |
Wavelength range (not less than 60 lines of CO2
VR spectrum) |
9
–11 microns |
|
2.4.3. |
Angular divergence |
3.5
mrad |
|
2.4.4. |
Frequency stability |
±1 MHz |
|
2.5. |
Helium-Neon
laser (2 pcs) |
|
|
2.5.1. |
Power |
15
mW |
|
2.5.2. |
Wavelength |
632.8
nm |
|
2.5.3. |
Angular divergence |
2
mrad |
|
3. |
Receiving unit
characteristics |
|
|
3.1. |
Receiving telescope
|
|
|
3.1.1. |
Light diameter |
500
mm |
|
3.1.2. |
Optical quality (for l = 10 mcm) |
better
than l/4 |
|
3.2. |
Receivers |
|
|
3.2.1. |
Mercury-Cadmium-Tellurium heterodyne matrix
(5x5 elements) |
l = 9 – 11 mcm |
|
3.2.2. |
Avalanche photodiode |
l = 1 mcm (NIR) |
|
3.2.3. |
Photomultiplier |
l = 300-450 mcm |
|
3.3 |
Targeting
device – CCD camera with zoom |
Video standard |
|
3.3.1 |
Field of view (variable) |
5 – 25 mrad |
)* -
at the perfect visibility conditions (not less than 15 km)
)**
- for SO2 diagnostics
)***
- for NO2 diagnostics
)****
- with automatic scanning.
4.
Automation and software
The
following adjusting and working operations in the lidar system are performed
automatically, controlled by computer:
·
Tuning of the emitting lasers wavelength onto the
absorption line of the specie under investigation
·
Scanner scanning to search and guide the objects
·
CCD-viewer operation to coincide the landscape image
with the lidar data
·
Search-mode to DIAL-mode change
·
and many others.
Lidar
data treatment is performed by means of powerful on-board computer equipped
with ADSP special processor allowing to apply original real time algorithms of received
signal deconvolution. Atmospheric species identification is founded on the
application of both HITRAN® and original databases including the
detailed information about gaseous species absorption crossections for
different spectral ranges.
5.
Special abilities
According
customer’s request the lidar complex can be optionally equipped with the
systems, which significantly extend its possibilities:
·
IR radiometer (determination of fires, explosions,
hot gases exhausts)
·
IR high speed scanning Fourier spectrometer (precise
determination of pollutants having the complicated molecular structure such as
gaseous poisonous and toxic agents)
·
Wind velocity (CO2 heterodyne lidar)
Please, for additional information
see: http://www.iltt.ru