Aircraft velocity-altitude measuring means
AssigneeCarl-Zeiss-Stiftung
InventorsReinhard Prinz, Karl Felle
Life of this patent
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Abstract
The invention contemplates use of a cylindrical lens oriented transverse to an aircraft axis, in conjunction with two light-sensitive detectors in the image plane of the lens, to develop two time-displaced electrical output signals which represent aircraft-motion scanning of terrain by the respective detectors; basically simple circuitry develops the velocity-altitude ratio by measuring the instantaneous displacement time between the two signals. The same cylindrical lens and detecting circuitry may be provided in multiple and in particular relative orientations, to additionally develop drift-angle of the aircraft axis with respect to its instantaneous ground-velocity vector.
Claims10
An aircraft velocity/altitude measuring device, comprising two terrain-viewing cylindrical lenses disposed for direct viewing of terrain and fixedly related to each other in an orientation such that their cylinder axes are generally transverse to but at an angle extending on opposite sides of the aircraft axis, said angle being large enough to embrace the direction of the flight-velocity vector for the widest possible extent of drift-angle heading of the aircraft, whereby passing terrain features are converted by said lenses into line structures having said fixed angle relation and moving in the image planes of the respective cylindrical lenses, means including two spaced light-sensitive detector regions in the image plane of each cylindrical lens for producing separate time-varying electrical signals the time-shift between which is respectively proportional to the speed of movement of the line structures in the respective image planes of said cylindrical lenses, said spacing being in the direction perpendicular to the cylindrical axis of the associated cylindrical lens, and means for comparatively evaluating said separate electrical signals, said last-mentioned means including for the two detector regions associated with each cylindrical lens a separate comparator producing from said separate signals a voltage of amplitude corresponding to the associated time-shift.
An aircraft velocity-altitude measuring device, comprising optical means consisting of two terrain-viewing cylindrical lenses disposed for direct viewing of terrain and fixedly related to each other in an orientation such that their cylindrical axes are at an angle extending on opposite sides of the aircraft axis, said angle being large enough to embrace the direction of the flight-velocity vector for the widest possible extent of drift-angle heading of the aircraft, whereby passing terrain features are converted by said lenses into line structures having said fixed-angle relation and moving in the image planes of the respective cylindrical lenses, means including a pair of spaced light-sensitive detector regions in the image plane of each cylindrical lens for producing two separate time-varying electrical signals, each said spacing being in the direction perpendicular to the cylinder axis of the associated cylindrical lens, whereby a time-shift exists as between the two separate time-varying signals associated with each cylindrical lens and such time-shift is proportional to the speed of movement of the line structures in the respective image planes of said cylindrical lenses, first means for comparatively evaluating the separate electrical signals of a first pair of detector regions to produce an output voltage of amplitude corresponding to the time-shift associated with one of said cylindrical lenses, second means for comparatively evaluating the separate electrical signals of the other pair of detector regions to produce an output voltage of amplitude corresponding to the time-shift associated with the other of said cylindrical lenses, and means comparatively responsive to both said output voltages for producing a voltage proportional to the instantaneous velocity/altitude function of the aircraft.
Dependencies are inferred from the claim text.