Deutsche Forschungs- Und Versuchsanstalt Fur Luft- Und Raumfahrt E.v.

Dieter Lorenz

A system for measuring electromagnetic radiation originating from the hemhere corresponding to a solid angle of 2.pi. is provided wherein a highly sensitive low-inertia detector is disposed below a transmissive dome and wherein the chopped light detection method is utilized. There are provided above the transmissive dome two similarly or differently designed modulators which are in the shape of dome segments and which are fitted into each other. At least one of the modulators rotates about their common vertical axis or the modulators may both rotate about the common vertical axis, either at the same or a different speed in the same direction or in opposite directions.

System for measuring electromagnetic radiation originating from the

An electromagnetic radiation detecting device comprises at least one radion detector for detecting electromagnetic radiation from a hemisphere, a radiation-transparent protective hood covering the or each detector, and a rotary chopper to alternately shield the or each detector and associated hood from arriving radiation and to expose the detector and hood to such radiation. The chopper comprises a carrier disc, which is rotatable about an axis parallel to a radiation-receiving area of the or each detector, and at least one hollow semicylindrical shielding member fixed at the periphery of the disc and curved in the axial direction of the semicylindrical shape. The or each shielding member is movable on a circular path by the disc to alternately shield and reveal the hood covering the or each detector.

Electromagnetic radiation detecting device with hollow semicylindrical

In order to avoid the encumbrance of a rotary mirror scanner by large calating radiation sources for intermittently illuminating the detector element of the scanner, a supplementary radiometer responsive to the same scene as is scanned is absolutely calibrated by intermittent illumination from calibrating sources that are conveniently small. The calibrated radiometer signal is compared to portions of the scanner output responding to the same object field, for calibration of the scanner output. The radiometer may be scanned at right angles to the direction of scan of the scanner in order to provide calibration of both the forward cross lines and rear cross lines alternately scanned by a stereoscopic scanner, for stereoscopic observation of cloud formations, land masses, air traffic distribution or the like from a space craft.

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Hohenpeissenberg, Germany

Dieter Lorenz