RADIO DIRECTION FINDING SYSTEM

• US 3,845,487 A
• Filed: 09/26/1972
• Issued: 10/29/1974
• Est. Priority Date: 09/26/1972
• Status: Expired due to Term

• Current Assignee: Uve H.W. Lammers
• Original Assignee: Uve H.W. Lammers
• Inventors: Lammers, Uve H. W.
• Primary Examiner(s): Hubler, Malcolm F.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US05/292,370
• Time in Patent Office: 763 Days
• Field of Search: 343/113DE
• US Class Current: 342/418
• CPC Class Codes: G01S 3/54 the apparent movement of the antenna being produced by coupling the receiver cyclically and sequentially to each of several fixed spaced antennas

Abstract

A radio direction finding system measures the angle of arrival of a distant-source signal using a moving receiving antenna or moving reflector from which first and second doppler shifted signals propagate along and against its direction of motion. Angular information is obtained by comparing the two signals. The position scan of the antenna is simulated.

Claims

1. A radio direction finding system depending on the angle dependent doppler shift imposed on a distant-source signal of frequency f comprising a single antenna exclusively receiving said distant source signal, said single antenna having an electronically simulated motion, first and second doppler shifted signals of frequencies f1 and f2, respectively, propagating along and against the direction of motion of said single antenna, first and second terminals receiving said first and second doppler shifted signals, respectively, said single antenna being positioned between said first and second terminals, means to add only the frequencies f1 and f2 of said first and second doppler shifted signals, respectively, to obtain a second resultant frequency signal, and means to divide said first resultant frequency signal by said second resultant frequency signal to obtain the angle of arrival measurement.

2. A radio direction finding system as described in claim 1 wherein said single antenna is comprised of a stationary waveguide having a slot along the length thereof, a multiplicity of diodes equally spaced at a predetermined distance from each other along said slot and connected between said slot and ground, said diodes normally presenting a short circuit to the incoming signals, and means to sequentially open the diode short circuits, each of said diode short circuits being open for a predetermined length of time to simulate motion along said slot.