Sun Sky Multiband Photometer

Remote sensing instruments




The CE318-N carries out raw measurements according to automatic standardized scenarios: sun and sky radiance on several bands

Raw measurements can be automatically post-processed to retrieve a large number of atmospheric parameters, including :

        • Optico-physical characterization of aerosols (size distribution, complex refraction index , shape)
        • Optical properties of the atmosphere (Aerosol Optical Depth, phase function, single scattering albedo, amount of precipitable water vapor….)

The large range of produced parameters makes the CE318 photometer a worldwide benchmark instrument for the following applications:

        • Climate and climate change studies
        • Air quality monitoring and forecast
        • Near real time detection of volcanic ash plumes
        • SDS (Sand Dust Storm) monitoring and forecast
        • Correction of satellite images
        • Satellite calibration for aerosol measurements
        • Ocean's color monitoring


Precision and high reliability

      • Most wide-spread  and scientifically validated instrument
      • Several standard and entirely automatic scenarios of measurements
      • High measurements stabilityon the long term, even in harsh climatic conditions

Proven robustness under any climate

      • More than 1000 instruments operating around the world
      • Continuous operating even under extreme climatic conditions
      •  Reinforced protection against lightning
      • High robustness and resistance to  corrosion (over 15 years)
      • Reduced regular maintenance

Flexibility of use

      • Suitable for  long-term installation within observation networks as well as for  field  campaign measurement
      • Operates without any human attendance in a fully automated way with its own solar generator
      • Communicates either to a PC or fully autonomously via a satellite beacon


MicroAmps® technology

The CE318 photometer takes advantage from the unique Cimel MicroAmps® technologies that results in meeting several very demanding yet complementary specifications:

      •  Minimize electrical power consumption
      •  Use secure, highly redundant communications protocols
      •   Maximize the versatility of printed circuit boards
      •   Minimize the number of connectors

These MicroAmps® technologies result in CE318-N photometer exceptional performances widely proven under any sort of climate, in terms of reliability

Optical sensor head

      • Includes two detectors in order to cover the entire spectrum from 340 nm to 1640 nm
      • Optical line-of-site channel for each detector with a narrow, well precisely defined field of view (1.3°)
      • Single-band precision filters inserted in the optical path
      • Motor-driven filter wheel positions each of the nine filters in turn
      • Second motor-driven filter wheel adds polarization filters (in three directions) for  models with polarization
      • Silicon photodiode detectors for the UV and visible spectrum, and InGaAs detectors for IR.
      • Extremely sensitive, low-noise, resistant to changes in temperature
      • A dual external collimator mounted on the head eliminates all stray light.

High precision robot

      • CE318 Automated mount

        Two high-resolution driven systems with an original backlash integral adjustment due to a Cimel custom technology

      • High sensitivity tracking system based on four-quadrant detector

Control unit

Accuracy enhancement

      • Drives the tracker with higher resolution and faster motions
      • Equipped with a built-in barometer ti automatically register the local atmospheric pressure
      • Now connected to a pyranometer for additional measurement and transmission of the global solar radiation

CE318  control unit

The internal memory includes an SD card with virtually unlimited capacity (no risk of data loss)

Better convenience of use

      • Larger and backlit built-in display for better reading and navigation through enhanced menus in good lightning conditions
      • Built-in GPS for automatic data localization and time synchronization
      • All control, data acquisition, storage and communication functions are integrated within a single metallic and hermetic control box, of high robustness



        • The  instrument performs preprogrammed tasks several times per day, according to various patterns:

- Direct solar measurements: sun tracking and triggering of a multi-band measurement cycle

- Sky measurements: positioning according to a main plan or to almucantar and triggering of a measurement cycle at several angles in the plan

        • Keyboard-display interface for configuring the instrument and checking operation is available to the users


        • Measured data are automatically stored by the control unit and may be transferres in real-time to a local PC over an RS-232 connection (maximum length: 100 m)
        • For isolated locations, the control unit automatically transfers data during allocated time slots to geostationary satellites (GOES, METEOSAT, GMS, ...) through a satellite beacon

Post processing


For AERONET members, data may be automatically transferred to the AERONET central system that performs normalized post-processing and quality controls.

See AERONET Site for more details


Cimel provides its AstpWin inversion software free of charge.It performs the following:

          • Acquisition and storage of raw data
          • Representation of the Beer-Lambert-Bougher law (for calibration purposes)

It also includes an inversion software developed by the University of Granada that allows to produce the following columnar parameters:

          • Cloud detection and data filtering
          • Daytime Aerosol Optical Depths (AODs) at each wavelength and water vapor content
          • Aerosol size distribution
          • Phase function for each band
          • Asymmetry parameter
          • Single scattering Albedo...

Technical features

Specifications Value
Measurement Irradiance precision measurement < 0.1%
Well precisely defined field of view 1.3°
Minimal scatterring angle (from the sun)
Wide spectral range 340 to 1640 nm standard (for more, see options)
Optical new technology  filters Derivation:< 1% / year
Automated mount 2 axis for  whole sky angular scanning(0°-360°, 0°-180°)
Mechanical  precision 0.05°
Solar tracking precision(automatic tracking) 0.1°
Power consumption < 2 W
Environmental conditions Temperature


-30°C to 70°C

0 to 100% RH

General Total weight with support 38 kg


CE318 deployment in Tamanrasset (Algeria)









CE318 deployed




CE318 deployment in polar environment

Optional accessories

Head types

Several sensor head models are available, according to desired application:

Reference Description Filters Applications
318-NE BS9 Standard model with 9 filters 340, 380, 440, 500, 670, 870, 936, 1020, 1640 nm Standard
318-NE DPS9 Polarized model 340, 380, 440, 500, 670, 870, 936, 1020, 1640 nm

Polarization in three directions

Polarized  & non polarized measurements
318-SEAPRISM Measurement of luminance emerging from the water surface 412,440,500,531,550,675,870,936,  1020 nm Ocean color
318-BRDF BRDF measurements 380, 440, 550, 675, 740, 870, 936, 1020, 1640 nm Satellite calibration
318-U LUNAR Moon-specific 440, 500, 670, 870, 936, 1020, 1640 nm Night-time and polar region measurements


CE318 optional accessories

Accessory  Sales reference Description Characteristics Applications
Heating robot CE316-HEAT Robot with built-in heating system To be used in very cold climates (prevents freezing) Cold & polar climates
Kit Satellite T440-kit-318S Satellite transmission system Beacon, GPS, antenna, solar powered Remote sites