Method and apparatus for four-beam radar

• US 4,633,256 A
• Filed: 12/10/1984
• Issued: 12/30/1986
• Est. Priority Date: 12/10/1984
• Status: Expired due to Fees

• Current Assignee: THE GOVERNMENT OF THE UNITED STATES OF AMERICA, AS REPRESENTED BY THE SECRETARY OF COMMERCE
• Original Assignee: THE GOVERNMENT OF THE UNITED STATES OF AMERICA, AS REPRESENTED BY THE SECRETARY OF COMMERCE
• Inventors: Chadwick, Russell B.
• Primary Examiner(s): Blum, Theodore M.
• Assistant Examiner(s): Gregory, Bernarr Earl
• Application Number:
  US06/680,114
• Time in Patent Office: 750 Days
• Field of Search: 343/525, 343/5 W, 343/9 R, 343/368, 343/371-374
• US Class Current: 342/368
• CPC Class Codes: G01S 13/951 ground based
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H01Q 3/38 the phase-shifters being digital
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A method and apparatus for producing remote profiling beams pointing altetely to the north, east, west or south by ordered distribution of phase shifts to elements of a square antenna array. Elements within a given group of four array elements share a related group of four phase shift means. Elements in a group trade phase shift means intragroup but there is no intergroup trading. The arrangement permits four-beam capability without unduly increasing the cost or complexity of the radar assembly over prior art assemblies. Also disclosed is a system for "tipping" the array either virtually or physically to obtain a vertical beam.

Claims

1. A four-beam radar apparatus comprising:

means for generating a driving signal;

means connected to said generating means, for splitting said driving signal into 4n² driving signals where n is a nonzero positive integer;

4n² phase shifters divided in a predetermined fashion into n² phasing groups of four phase shifters apiece for generating predetermined phase shifts;

4n² array elements arranged in a 2n×

2n square matrix divided in a predetermined fashion into n² element groups of four array elements apiece;

n² switching means respectively associated with one of said n² phasing groups and one of said n² element groups for selectably and alternately interconnecting said four elements in said element group and said four phase shifters in said phasing group in one of four alternate predetermined interconnections;

said 4n² array elements being arranged at positions (±

j, ±

k) where j and k are positive integers between one and n inclusively;

each ordered coordinate pair j, k determining one of said n² element groups; and

each ordered pair j, k determining one of said phasing groups, the four phase shifts being created by said group being determined by the product of a unit phase shift times ±

x or ±

y, where x equals (j+k-1), and where y equals (j-k).

2. A four-beam radar as claimed in claim 1, wherein the frequency of said driving signal is 400 MHz, and said unit phase shift is equal to 76°

.

3. A four-beam radar as claimed in claim 2 wherein n equals 5.