Device for aircraft and spacecraft for producing a digital terrain representation

• US 4,689,748 A
• Filed: 03/20/1986
• Issued: 08/25/1987
• Est. Priority Date: 10/09/1979
• Status: Expired due to Term

• Current Assignee: Lfk-Lenkflugkã¶Rpersysteme GmbH (MBDA)
• Original Assignee: Messerschmitt-Bolkow-Blohm Gesellschaft Mit Beschrankter Haftung
• Inventors: Hofmann, Otto
• Primary Examiner(s): Krass, Errol A.
• Assistant Examiner(s): Cosimano, Edward R.
• Application Number:
  US06/842,066
• Time in Patent Office: 523 Days
• Field of Search: 324/330, 343/5 CM, 343/5 MM, 353/5, 353/6, 353/11, 353/12, 364/454, 364/456, 364/518, 364/571, 364/577, 364/515, 364/424, 358/103, 358/105, 358/109, 382/34, 382/42
• US Class Current: 701/223
• CPC Class Codes: G01C 11/025 by scanning the object

Abstract

A device for use on aircraft or spacecraft provides data corresponding to the course and orientation of the craft, and a digital display of the terrain over which the craft is travelling. The device includes at least first, second and third sensor lines consisting of parallel rows of photosensitive semiconductor elements arranged transversely of the flight path of the craft. The sensor lines provide line images corresponding to terrain images directed onto the lines, and the lines are spaced apart from each other so that a first terrain image sensed by the lines during a first scanning period partially overlaps a second terrain image sensed by the lines during a second, successive scanning period. The device also includes a lens system for continuously directing the terrain images onto the lines, and systems for reading out and storing the line images from the sensor lines during each scanning period and for correlating certain picture reference points in the second terrain image with the same picture reference points in the first terrain image. A computer then operates to determine the orientation of the second terrain image in accordance with intersections, at each of the picture reference points on the terrain, of homologous image rays produced during the first and second scanning periods.

Claims

1. Method for providing data corresponding to the course and orientation of an aircraft or spacecraft which travels along any arbitrary flight path, and for providing data corresponding to a digital three-dimensional representation of the terrain over which the craft travels by utilizing a device including first, second and third parallel sensor lines each consisting of a row of photosensitive semiconductor elements arranged transversely of the flight path and spaced apart from each other by distances corresponding to a certain image base, and at least one lens system for continuously directing terrain images onto said sensor lines, said sensor lines and said at least one lens system being arranged so that a first sensor line A looks forwardly and a third sensor line C looks rearwardly with respect to the direction of flight and to a second sensor line B looking downwardly, the method comprising the steps of:

simultaneously generating by means of said sensor lines at least three sequences of line images, these line image sequences corresponding to a forwardly, a downwardly and a rearwardly looking perspective, and the successive line images of each said line sequence are generated during successive scanning periods and during a scanning period generating one forwardly, one downwardly and one rearwardly looking line image;

selecting at least five orientation points on the rearwardly and downwardly looking line images newly generated during the same scanning period;

determining by way of correlation the corresponding image points on the downwardly and forwardly looking line images, respectively, which are backwardly offset;

computing the orientation and position parameters of the newly generated line images relative to the backwardly offset line images by intersection of homologous rays passing through said orientation points and said corresponding image points on the one hand and through their related projection centers given by said lens system on the other hand; and

computing the corrdinates of each terrain point by spatial intersection.