Method for acquiring azimuth information

• US 6,718,264 B2
• Filed: 03/26/2002
• Issued: 04/06/2004
• Est. Priority Date: 03/28/2001
• Status: Active Grant

• Current Assignee: Masato Takahashi
• Original Assignee: Communications Research Laboratory Independent Administrative Institution, Masato Takahashi
• Inventors: Takahashi, Masato
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Hernandez, Olga
• Application Number:
  US10/105,315
• Publication Number:
  US 20020183926A1
• Time in Patent Office: 742 Days
• Field of Search: 701/213, 701/200, 701/215, 731/78.R, 342/1, 342/73
• US Class Current: 701/213
• CPC Class Codes: G01S 19/36 relating to the receiver frond end
• CPC Class Codes: G01S 19/53 Determining attitude

Abstract

A method for acquiring azimuth information is provided in which first and second planar patch antennas (11a, 11b) are disposed so that their sky coverage areas partially overlap to form a common area (2), thereby dividing the antenna sky coverage area into a first area (1), third area (3) and common second area 2, and an azimuth is limited utilizing azimuths acquired in the respective areas and the angle between the two antennas. As a result, azimuth limitation information can be effectively acquired even at a location where the sky is severely blocked and satellite information can be adequately acquired only at a small range of sky visibility.

Claims

1. A method for acquiring azimuth information comprising:

a step of vertically disposing a pair of planar antennas each having a hemispherical antenna pattern at an angle to each other such that their sky coverage areas partially overlap;

a step of detecting the angle formed between the antennas;

a step of causing a GPS receiver connected to each antenna to attempt reception of signals transmitted by GPS satellites in the sky coverage area of the respective antenna to which the GPS receiver is connected;

a step of comparing the satellite signals acquired and discriminating in which of three separate sky coverage areas the satellite that transmitted each signal is present;

a step of in each of the three areas creating a clockwise series of satellite azimuths and extracting the azimuth of the first term and the azimuth of the last term; and

a step of limiting the azimuth of a direction based on the azimuth of the first term and the azimuth of the last term in at least one area and the angle formed between the two antennas.

2. A method for acquiring azimuth information according to claim 1, wherein said at least one area is a common area where the sky areas of the two antennas overlap.

3. A method for acquiring azimuth information according to claim 1 or 2, wherein the presence of a single satellite in said at least one area makes the azimuth of the first term and the azimuth of the last term the same.

4. A method for acquiring azimuth information according claim 1, wherein azimuth limitation results acquired in multiple areas are limited to a single azimuth by taking a common product of sets.