European Facility For Airborne Research

European Facility For Airborne Research June 28, 2022, 23:20

Instrument: INTA Greyscale Precipitation Probe

Name INTA Greyscale Precipitation Probe
Acronym DMT-2DGB2
Manufacturer Droplet Measurement Technologies
Manufacturer website
Operated by INTA
Operated onboard

Instrument type

Name Optical Array Probe (OAP)
Acronym Optical Array Probe

Principle of operation

Measured parameter Particle shadow area/diameter
Operating principle

Optical array probe. Cloud particle enters field of view passing through a laser beam. Particle shadow falls on a collecting optical array (normally a photodiode array). This is sampled at a rate such that the pixel resolution in time is the same as that in the across-array dimension. This forms a digitized shadow image of the particle.
From this size and shape are determined, and bulk parameters such as concentration and size spectra derived. Empirical relationships are used to calculate the mass of irregular particles (and hence the ice water content).

Measurement(s) Clouds & Precipitation

Dimension and weight

External dimension Length: 101.5cm. Diameter: 17.8cm. It can be mounted on a PMS canister
Weight 18.0


Operating mode In situ






Operational restriction

Environmental: Temperature (-20&degree;C to +40&degree;C)
Humidity (0 to 100 % non-condensing)
Altitude (0 to 60.000 ft ( 0-18,3 km))

Operational requirements

Probe power 115VAC 50-400Hz 1 A
Heater power 28VDC 220W

Certification approvals

Certified for all A/C

Additional information

The Optical Array Probe Grey Scale Model OAP-2D-GB2 acquires information on particles passing through the
sample area in a form suitable for digital handling. The output bit stream
encodes not only the presence of a particles plus three levels of “grey”
information on the form of the particle image.
Particle information is acquired using a linear array of photodiodes to sense the shadowing of array elements by
particles passing through its field of view. Particles are illuminated by a He-Ne laser and imaged as shadowgraphs onto the photodiode array. If the image is dark enough on a particular element of the array, the output of a comparator will switch and provide output from an amplifier card.

Access, host and processing


Consult INTA

Could also fit on any aircraft having the following characteristics

General description

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