INQUIRY-REPLY SYSTEM IN PARTICULAR SECONDARY RADAR DEVICE

• US 3,805,264 A
• Filed: 10/30/1970
• Issued: 04/16/1974
• Est. Priority Date: 11/14/1969
• Status: Expired due to Term

• Current Assignee: Gerhard Wagner, Rudolf Bock
• Original Assignee: Gerhard Wagner, Rudolf Bock
• Inventors: Bock, Rudolf, Wagner, Gerhard
• Primary Examiner(s): Tubbesing, T. H.
• Application Number:
  US05/085,557
• Time in Patent Office: 1,264 Days
• Field of Search: 343/6.5R,18E
• US Class Current: 342/13
• CPC Class Codes: G01S 13/762 with special measures concerning the radiation pattern, e.g. S.L.S. aerials or aerial systems providing at least two radiation patterns, e.g. providing sum and difference patterns, H01Q25/00

Abstract

An inquiry-reply system utilizing a primary inquiry antenna which has a distinctive main lobe radiation pattern and less distinctive and smaller side lobes. An additional antenna is provided which has directional sensitivity arranged to be weakest in the area of the main lobe of the primary inquiry antenna and to be at a maximum in the vicinity of the side lobes of the antenna. False information is radiated by the additional antenna to disguise the inquiry code in the regions of the side lobes.

Claims

1. A secondary radar interrogation answer system having an interrogation antenna with a main lobe and a number of side lobes, coded interrogation pulse signals being emitted via the interrogation antenna, an additional antenna having directional characteristics which include a minimum in the range of the main lobe and emitting signals additional to the coded interrogation signals, the impulses being emitted by the additional antenna being positioned within the time space of the coded interrogation signals and at intervals where no interrogation pulse is present whereby the signal outside the region of the main lobe is falsified.

2. An inquiry reply system in accordance with claim 1 wherein the directional characteristics of said additional antenna are adapted to the radiation pattern of said inquiry antenna in the region of the side lobes thereof.

3. An inquiry reply system in accordance with claim 1 wherein the additional antenna is constructionally secured to the inquiry antenna.

4. An inquiry reply system in accordance with claim 3 wherein the transmitter for the additional antenna is constructionally attached to the inquiry antenna.

5. An inquiry reply system in accordance with claim 1 wherein an inquiry antenna and the additional antenna have the same polarization.