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:
Jun. 21, 1977
Filed:
Nov. 10, 1975
Eric J Isbister, Greenlawn, NY (US);
Sperry Rand Corporation, New York, NY (US);
Abstract
A navigation system in which a transmitter-antenna combination radiates two independent signals with a known frequency separation there between. These signals are radiated to an antenna on a navigation marker whereby they are received and directed to a non-linear device in which signals at the fundamental frequencies and frequencies that are linear combinations of the two fundamental frequencies are generated. These generated signals are then guided to the antenna and retro-directively re-radiated. The re-radiated signals are received by an antenna at the transmitting location and directed to a receiver wherein the fundamental frequencies and the desired linear combination thereof are detected and processed to provide the locations and identification of the navigation markers.