Applications

FAQ

How much does a Raymetrics LIDAR cost?

Raymetrics specialises in customised LIDAR solutions, tailoring our designs to suit our clients' needs.  As a rough guide, the simplest system would usually be around 100,000

€, rising to over 300,000 € for extremely large, multi-channel Raman or DIAL systems.  These prices should however only be seen as a guide – actual price depends greatly on the final specifications.  We pride ourselves on constructing LIDARs which meet user requirements, but also fit within their budgets.  Please contact mwoollard@raymetrics.gr to discuss your LIDAR needs and obtain a quotation.

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What is a LIDAR?

LIDAR is an acronym of Light Detection And Ranging.  A laser emits a beam of light which is scattered by target particles in the atmosphere.  Part of the light is returned or “backscattered” to a telescope placed alongside the laser.  The returned light can provide a wealth of information about the atmosphere.

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What is the range of Raymetrics LIDARs?

We usually quote an "effective range" of 12-15 km for LIDARs with a 200 mm telescope, up to 20 km with larger telescopes.  Actual values depend strongly on the atmospheric conditions.  In ideal conditions a LIDAR with a 200 mm telescope would be able to detect even further (20 km or even further - raw signal goes up to ~60 km), but in poor conditions the signal can be reduced.  That is why we find it more useful to our clients to quote the range they are likely to be able to measure regularly at - an "effective range" of 12-15 km. 

Raymetrics LIDARs have several advantages which result in our LIDARs having greater effective range compared to our rivals.  These include a large telescope (200 mm minimum), more powerful lasers, high quality optical components, and a much narrower field of view (other companies often provide systems which are “permanently aligned”, meaning the telescope has a large field of view which is not focused tightly on the laser beam path, introducing increased noise and reducing effective range).

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How can I find out EXACTLY how much my LIDAR will cost?

Contact mwoollard@raymetrics.gr for a quotation.  Please provide as much information as possible about necessary specifications, and/or about the intended uses of the LIDAR.  Answering the following questions would enable us to tailor the system exactly to your needs:

A)      Would you like the system to be vertical or have the ability to rotate and scan in 3D?  (Note:  Standard scanningsystems come with a maximum of 3 detection channels and a200 mm telescope – other configurationswould need a customised build)

B)      Would the LIDAR be for indoor or outdoor storage/use?

C)      Would the laser need to be eye-safe (e.g. 3D scanning in populated areas, or vertical emission where there is a danger of aircraft passing overhead, etc)?

D)      Would the LIDAR ever be used at temperatures lower than -5°C or stored at temperatures below 0°C?

E)      Are you considering upgrading your system later on (e.g. a Backscatter LIDAR to a Raman LIDAR, a vertical deployment to a scanning system)? 

F)      What sort of range were you hoping to achieve (Raw signal is ~60km, but effective range is ~12-15 km for systems with 200 mm telescopes, up to 20 km with larger telescopes and more powerful lasers – larger telescopes are also advised for detecting the weak Raman signal)?

Are there any special requirements you have for the system (e.g. anti-vibration mechanism forsafertransport on a vehicle, customised housing shelter, etc)?

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What can Backscatter LIDARs be used for?

Raymetrics LB Series models are relatively simple backscatter LIDARs.  Parameters detected are the range corrected signal (colour plots of aerosols and cloud distributions), attenuated backscatter coefficient (calibrated range-corrected signal), and under certain conditions (e.g. additional detection channels), extinction coefficient, depolarisation ratio, colour ratio and Angstrom exponent (backscatter related).

Backscatter LIDARs are suitable for detecting clouds, dust layers, the planetary boundary layer, and with multiple channels they can also be used to a degree for aerosol type discrimination (dust, anthropogenic).

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Does Raymetrics provide training?

Yes.  On delivery of any Raymetrics Lidar, we arrange for an engineer to arrive on site to set up the system.  The engineer will remain with the client for 3 days to train users.  This service is provided with all Lidars we sell.

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What about after-sales service?

We provide a comprehensive warranty for the first year, which includes technical support by phone or email.  After the first year we can offer several different options for a service contract, which would include continued phone and email support, as well as an annual visit from an engineer to fully check, clean and service the LIDAR.  Details of service contracts are sent out as part of any complete technical and financial offer.

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What can Raman LIDARs be used for?

The use of a Raman LIDAR is a well-established method of determining the vertical profile of the aerosol extinction coefficient independently from the aerosol backscatter coefficient.  This results in a dramatic reduction in the associated uncertainties, making a Raman system more accurate than a Backscatter system.

In addition to the parameters detected by backscatter LIDARs, Raman LIDARs also detect the extinction-backscatter ratio, aerosol extinction coefficient, optical depth, LIDAR ratio, Angstrom exponent (extinction related), single scattering albedo (aerosols).

Uses of a Raman LIDAR include aerosol type determination (dust, maritime, fire smoke, urban haze), water vapour profiles, temperature profiles, and detecting aerosol microphysical properties (volume and surface concentrations, refractive index).

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What is the DIAL Technique/LO Series DIAL Ozone LIDAR?

Differential Absorption LIDARs (DIAL) can detect almost any “classical” gases.  This technique utilises multiple emission and detection channels, comparing the results of wavelengths of light which are strongly absorbed by target particles with wavelengths which are weakly absorbed.  In this way, concentrations of target gases can be measured.  This set-up results in a very large and relatively expensive LIDAR system.  To date, Raymetrics has developed a Differential Absorption LIDAR (DIAL) system specifically designed for studying ozone – the LO Series LIDAR.  DIAL LIDARs for other gases can be developed upon request.  Gases which could potentially be detected include O3, NO2, NO, N2O, SO2, CH4, HCl, NH4, and others.

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What are the consumables?

For most of our “classical” LIDARs, the consumables are flashlamps for the laser, deionisation cartridges and deionised/distilled water for the closed-circuit laser cooling system:

  • Flashlamps - expected lifetime >50 million shots (warranted 30 million) – e.g. with fairly heavy LIDAR use (6 hours per day for 25 days a month) replacement would be every 3-4 months
  • Deionisation cartridges (change every 6 months, along with changing ionised water in the closed loop laser cooling system – good practice to change with flashlamps)
  • Recommended:  Every 4 - 5 years the reflecting mirrors in the transmission unit should be recoated (or replaced).  Every 4 - 5 years the protective enclosure windows should be recoated.
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What are the advantages and disadvantages of Micropulse LIDARs (LM Series) compared to “classical” LIDARs (LB and LR Series)?

The major benefits of micropulse LIDARs (MPLs) are that they are less expensive, they are designed to be autonomous, they are always eye-safe, and they are smaller and hence more mobile.  MPLs are useful for detecting clouds, dust layers and the planetary boundary layer (the uses are fairly similar to those of a simple backscatter LIDAR).  

The benefits of “classical” LIDARs include a greater range of applications due to a greater range of options - e.g. multiple detection channels, Raman channels, etc.  Also, the lasers used in “classical” LIDARs are far more powerful, meaning that “classical” Lidars have greater effective range compared with MPLs.  It should also be noted that Raymetrics is also in the process of increasing elastic Lidar autonomy, for example through new software development which allows users to schedule regular measurements for unlimited periods of time.

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Do I need to purchase software?

No.  All software is included with all Raymetrics Lidars.  All software comes pre-installed on an integrated laptop which acts as a control unit for the Lidar and as a data storage unit.  Software includes programs for operating the Lidar, checking the Lidar is functioning, interrogating Lidar data, and visualising Lidar data.  No external software or hardware is necessary to fully make use of the system.  Our Lidars use binary data format for fast processing, but there is the option to export data as ASCII format for extensive compatibility with other software.  Graphs can also be exported as bitmaps or jpegs to quickly drop into reports and presentations.  We also provide unlimited licenses, meaning that software can be installed on other computers.

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Does Raymetrics provide Fluorescence LIDARs?

At present, we do not manufacture fluorescence LIDARs.  However, we have extensive knowledge of the technology and we would be interested in developing such tools.  Please contact mwoollard@raymetrics.gr to discuss. 

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Can my LIDAR be upgraded later on?

Almost certainly, yes.  Upgrades can be simple, such as additional detection channels, converting an LB Series backscatter model to an LR Series Raman model, or can be more complex, such as converting a vertical system to a scanning system.  If you have an idea of the sort upgrades you might need in the future, the initial design can in some cases be adapted to make upgrading easier. 

If you do not know what upgrades you may require, it does not necessarily matter – Raymetrics LIDARs are designed to be modular, meaning that most LIDAR designs come with several possible simple upgrades available – these will be listed in the technical offer specifications table of any quotation.

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Do I need Depolarisation?

Depolarisation provides a measure of how spherical or irregular the target particles are.  This is because spherical particles do not alter the polarisation state of linearly polarized laser light if it is scattered at 180º, whereas non-spherical particles do. 

Depolarisation has several applications, such as in characterising clouds as ice-bearing or water-bearing clouds, and helping to characterise other non-spherical particles such as partially crystallized acid droplets, desert dust and volcanic ash.

Raymetrics LIDARS are designed to allow for a unique method of calculating the depolarisation calibration constant.  For an accurate depolarisation ratio it is strongly suggested that the depolarisation constant is calculated.  Even small errors in this constant can introduce large errors in the depolarisation ratio. Raymetrics LIDARs are compatible with the +/-45° method for calculating the depolarisation constant. This procedure is a state of the art new method, proposed and applied by EARLINET members.  Through extensive research, Raymetrics now offers the easiest to handle and most precise depolarisation unit.  The user can conduct the +/-45° test quickly and also has the ability to correct the polarisation angle.

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Are Raymetrics LIDARs eye-safe?

LM Series micropulse LIDARs are always eye-safe.  Eye-safe solutions can be provided for almost all systems.  Only lasers emitting at 532nm cannot be eye-safe.

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Can the LIDAR be operated remotely?

Yes.  The distance between the Control Unit and the Lidar Head cannot be longer than around 10 m, but Raymetrics provides unlimited licences, meaning software can be installed on other computers.  The Lidar can then be operated remotely from another computer through its ethernet connection.

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Can I measure a specific type of gas?

It is possible to measure “classical” gases (e.g. NOx, SOx) with a Differential Absorption LIDAR (DIAL).  Also, the Laser Induced Fluorescence (LIF)techniquecan be used to distinguish almost any type of gas.  In LIF, a signal is emitted at the 266nm wavelength which hits target particles up to 2 km away and returns a full fluorescence spectrum to the telescope.  The peaks in the spectrum correspond to different gases.  Comparison of the data with extremely well-defined data tables means almost any type of gas can be distinguished(e.g. VOCs, chemical agents, etc).  This would however be a custom solution.  Contact mwoollard@raymetrics.gr to discuss.

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What are the major customisation options available?
  1. Deployment Type:  Vertical LIDAR or Scanning LIDAR.  In a vertical deployment the laser points in only one direction – usually straight up, to provide atmospheric profiles.  In a scanning deployment the zenith and azimuth angles are controlled by the user, providing 3D information, e.g. for detecting or mapping pollution sources.  Custom deployments are available – e.g. vehicle mounting, full enclosure with environmental control, radar for aircraft detection to switch off laser, etc.
  2. Size of Telescope:  200 mm or 400 mm are standard sizes, with other sizes available on request.  Larger 400 mm telescopes are provided for detecting higher up in the atmosphere (up to ~20 km effective range) and for detecting weak Raman signals.  200 mm telescopes are used for up to 12-15 km effective range, and for standard 3D scanning LIDARs. 
  3. Laser power:  The type and power of the laser can also be varied, depending on the range the LIDAR needs to detect at, and the wavelengths which are detected.
  4. Channels (Wavelengths) Detected:  These include backscatter channels at 355nm, 532nm, 1064nm, Raman channels at 387nm (nitrogen), 408nm (water vapour) and 607nm, and depolarisation channels. 
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Should my Backscatter LIDAR detect at 532nm or 355nm?

532 nm and 355 nm are both backscatter channels and are useful for similar applications.  355 nm is however less useful in heavily polluted environments (i.e. urban centres) as the lower energy signal rapidly deteriorates.  The scatterers 532 nm detects are larger and the signal is more powerful, hence the range of the laser is greater in urban environments compared to 355 nm. 

 

355 nm is preferable to use for example in a system designed to detect water vapour (with additional Raman channels), as the water vapour signal in the UV range is stronger than the signal in the visible range which would be returned from a laser emitting at 532 nm.  As 532 nm and 355 nm detect particles of slightly different sizes, comparison of the two signals can give a measure of the size of the scatterers – the Angstrom component.  A system set up for 355 nm can be easily adjusted to add a channel at 532 nm, but a system set up for 532 nm would require costly realignment of the laser (or would need to be set up initially ready for a 355 nm upgrade).

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Are Raymetrics LIDARs safe to use/store outdoors?

If a Raymetrics LIDAR is built for outdoor use, it will be rated IP56 on the International Protection Rating system.  The first digit relates to solids, meaning the enclosures are “Dust Protected”.  The second digit relates to liquids, meaning the enclosures have been tested with “Powerful Water Jets”.  They are therefore protected against weather.  Raymetrics LIDARs are also safe to operate and store in 0-100% humidity.  The standard temperature range without environmental control for safe operation is -5°C to 35°C, with storage safe from 0°C - 35°C.  Environmental control can be provided for both colder and warmer conditions.

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Can I measure continuously?

Yes.  The time interval can be controlled by the user and depends on the required range:  Longer times increases how far the Lidar will detect.  Views of the data in realtime are possible too.

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Can I detect water vapour profiles?

Yes.  We would recommend a vertical system with a 400mm telescope detecting at 355 nm, 387 nm and 408 nm for this application.  The large telescope is required to detect the relatively weak signal.  The 408 nm channel is the water vapour channel, and the 387 nm channel is a nitrogen Raman channel, which improves accuracy.  Although it is possible to detect water vapour profiles in the visible range (laser emitting and detection channel at 532 nm), we do not recommend this as the signal is weaker.

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I need a LIDAR for a slightly unusual application – can Raymetrics help me?

Quite possibly…  Raymetrics has a strong history in producing LIDARs for a range of purposes, including participation in research projects to develop new products.  Our emphasis on customised design means we are uniquely qualified to develop new solutions, even to problems which are not necessarily within the scope of our major product range.  Please contact mwoollard@raymetrics.gr to discuss your requirements.

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Can I detect Raman during the day?

The Raman signal during the day is masked by radiation from the sun.  We therefore do not claim that our Lidars can detect Raman signals during the day.  However, the high specification of our systems (i.e. large telescope compared to rival companies, more powerful lasers, high quality optical components, and much narrower field of view aligned perfectly to the laser) means that if any LIDARs were capable of detecting daytime Raman, it would be Raymetrics LIDARs. 

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Headlines

Partnerships

Through partnerships Raymetrics is able to augment its products with several other types of atmospheric LIDARs. These include wind doppler LIDARs for both the troposphere and stratosphere.

Raymetrics is also a distributor of OWIS Optical Beam Handling Systems and Positioning Systems.