Radio direction and position finding apparatus

• US 6,373,435 B2
• Filed: 01/31/2001
• Issued: 04/16/2002
• Est. Priority Date: 03/07/2000
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Akazawa, Hayato, Kurihara, Tsugihiro
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/772,932
• Publication Number:
  US 20010020916A1
• Time in Patent Office: 440 Days
• Field of Search: 342/430, 342/362, 342/427
• US Class Current: 342/430
• CPC Class Codes: G01S 3/36 the separate antennas having differently-oriented directivity characteristics
• CPC Class Codes: G01S 5/04 Position of source determined by a plurality of spaced direction-finders
• CPC Class Codes: H01Q 21/08 the units being spaced along or adjacent to a rectilinear path waveguide fed H01Q21/0037
• CPC Class Codes: H01Q 25/02 providing sum and difference patterns H01Q25/04 takes precedence
• CPC Class Codes: H01Q 3/28 varying the amplitude
• CPC Class Codes: H01Q 3/40 with phasing matrix

Abstract

An object of the present invention is to provide a selective level measuring apparatus with wider dynamic range of effective value detection, compared with the range by a conventional one. The apparatus according to the present invention comprises a gain control means arranged before an effective value detection section for varying a gain by a control voltage, so that a signal level inputted into the effective value detection section may be kept to be constant level by the gain control means, and the signal level of the signal to be measured is measured and indicated through the control voltage. Performing such operations allows the selective level measuring apparatus for the effective value detection to secure a dynamic range defined by a variable quantity of the gain control means. Accordingly, the present invention provides the wider dynamic range of the effective value detection comparing with that by the conventional one.

Claims

1. A direction and position finding apparatus for radio wave comprising:

a first directional antenna which rotates with a desired wave angle;

a first phase sum and difference combining means for outputting a sum and a difference of outputs from said first directional antenna;

a first differential gain control means for controlling a gain of the differential component of the output of said first directional antenna;

a first receiving means for receiving the sum component from said first phase sum and difference combining means;

a second receiving means for receiving an output from said first differential gain control means;

a first subtraction means for subtracting one output from the other output of said first and said second receiving means;

a first calculation means for determining a direction of arrival of radio wave based on an output from said first subtraction means;

a second directional antenna which rotates with a desired wave angle;

a second phase sum and difference combining means for outputting a sum and a difference of outputs from said second directional antenna;

a second differential gain control means for controlling a gain of the differential component of the output from said second directional antenna;

a third receiving means for receiving the sum component from said second phase sum and difference combining means;

a fourth receiving means for receiving an output from said second differential gain control means;

a second subtraction means for subtracting one output from the other output of said third and said fourth receiving means;

a second calculation means for determining a direction of arrival of radio wave based on an output from said second subtraction means; and

a position determining means for determining a position of an emission source of the radio wave based on outputs from said first and said second calculation means;

wherein said first directional antenna and said second directional antenna rotate interlockingly.

2. A direction and position finding apparatus in accordance with claim 1, in which said directional antennas use at least two or more vertical polarized waves.

3. A direction and position finding apparatus in accordance with claim 1, in which said apparatus uses a vertical polarized wave directional antenna with acute horizontal directivity and a vertical polarized wave directional antenna with acute vertical directivity.

4. A direction and position finding apparatus in accordance with claim 1, in which each of said first and said second phase sum and difference combining means can vary a phase difference in the output from each of said directional antennas.

5. A direction and position finding apparatus in accordance with claim 1, in which the position of the emission source of the radio wave is determined by controlling the gain of the differential component of the output from the directional antenna.