초록 ▼

A system for determining the ground velocity of an aircraft is disclosed. The system includes a CCD linear optical image sensor carried by the aircraft for forming a first and second substantially instantaneous light intensity contour of the optical image of the surface of the earth lying below the

A system for determining the ground velocity of an aircraft is disclosed. The system includes a CCD linear optical image sensor carried by the aircraft for forming a first and second substantially instantaneous light intensity contour of the optical image of the surface of the earth lying below the aircraft. The two contours are delayed in time with respect to each other. A computer, included in the system, compares the two contours to determine the relative position shift between the two contours by utilizing cross-correlation techniques. The computer then corrects the contour position shift for the aircraft altitude and divides the corrected position shift by the time delay between the two contours to obtain the aircraft ground velocity. A signal indicative of the aircraft ground velocity is output by the system.

대표청구항 ▼

Apparatus for determining the ground velocity of an aircraft comprising: at least one optical image sensor, which includes a plurality of image forming elements, carried by the aircraft; means for enabling said elements to form a first optical image of a first area of the earth\s surface and, after

Apparatus for determining the ground velocity of an aircraft comprising: at least one optical image sensor, which includes a plurality of image forming elements, carried by the aircraft; means for enabling said elements to form a first optical image of a first area of the earth\s surface and, after a time delay, enabling said elements to form a second optical image of a second area of the earth\s surface which overlaps in part with said first area; means for controlling the length of time said elements are enabled and said time delay; means for comparing said first image with said second image to produce a position shift signal representing the relative image position shift necessary to obtain the maximum degree of correlation between said first and second images; means for generating an altitude correction signal; means for multiplying said position shift signal by said altitude correction signal so as to produce a distance signal; and means for dividing said distance signal by said time delay to obtain a signal representing the ground velocity of the aircraft.