Vaisala Oyj

Jan Lönnqvist

Heikki Turtiainen

Atte Salmi

Jukka Kallio

Jouni Ikonen

Klaus Heyn

Seppo Mäkinen

Riitta Luukkala, Legal Representative

An example forward scatter sensor comprises: a transmitter arranged to emit a single light sheet; a receiver to observe light scattered from particles that fall through a measurement volume; and a control entity comprising an analyzer arranged to record a measurement signal descriptive of intensity of light captured by the receiver as a function of time and to carry out a precipitation analysis on basis of a time segment of the measurement signal, the precipitation analysis comprising: identifying, in said time segment, one or more double peaks that each represent a respective droplet and comprise a first peak that represents light refracted from a bottom of the respective droplet upon entry to the measurement volume and a second peak that represents light reflected from a top of the respective droplet upon exit from the measurement volume; and deriving one or more precipitation parameters and one or more precipitation indications.

Forward scatter sensor

An example forward scatter sensor comprises: a transmitter to emit a light sheet; a receiver to observe light scattered from particles that fall through a measurement volume; and a control entity comprising an analyzer to record a measurement signal descriptive of intensity of light captured by the receiver as a function of time and to: carry out a precipitation analysis on basis of a time segment of the measurement signal; carry out a verification of analysis performance based on magnitudes of first peaks of at least one identified double peak and on respective residence times for said at least one identified double peak; and invoke a predefined maintenance action responsive to said verification indicating a threshold-exceeding difference between respective size estimates derived based on magnitudes of the first peak of said at least one identified double peak and based on residence times of said at least one identified double peak.

The invention relates to a precipitation detector () and method for measurement of precipitation parameters. The detector () includes a frame (), a surface () mounted on the frame () and adapted to receive hydrometeors, and detection means () for converting the impact impulses of hydrometeors into an electric signal. According to the invention, the surface () receiving the impact of the hydrometeors is convex, stiff and rigidly connected to the detector frame () with the detection means () being permanently connected to the surface () receiving the impact of the hydrometeors.

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Helsinki, Finland

Jan Lönnqvist