The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 18, 1979
Filed:
Sep. 29, 1977
J Arnold Soltz, Boston, MA (US);
Glenn Mamon, Chestnut Hill, MA (US);
William A Drohan, Bedford, MA (US);
The Charles Stark Draper Laboratory, Inc., Cambridge, MA (US);
Abstract
A method and apparatus for surveying ground terrain from an airborne vehicle is disclosed. According to the method and apparatus, an inertial measurement unit, a position tracking device, and a terrain altimeter are carried by the airborne vehicle in a known vector relationship to one another. The inertial measurement unit provides continuous accelerometer data from which a first determination of vehicle position can be made. Simultaneously, data from the tracking device representative of the position of the tracking device relative to cooperating reflection means on the ground, if within sight of the airborne vehicle, provides, in combination with gimbal angle sensor outputs from the inertial measurement unit, an independent determination of the position of the vehicle. The two position measurements, when available, are continuously compared in real time on board the vehicle and error corrections are generated therefrom by estimation theory. The generated error corrections are stored and updated in real time and error correction signals are preferably provided to at least the inertial measurement unit to correct errors due, for example, to drift in the unit. The airborne vehicle can thereby be out of sight of the cooperating reflection means for substantial time durations without substantially degrading the accuracy of the position information. Corrected positional information, which includes the generated error corrections, and the correlated output of the terrain altimeter are stored to provide a profile of the region over which the vehicle flies. In preferred embodiments of the invention, both the position tracking device and the terrain altimeter are laser devices.