Radio-wave arrival-direction estimating apparatus and directional variable transceiver

• US 6,897,807 B2
• Filed: 04/05/2004
• Issued: 05/24/2005
• Est. Priority Date: 12/12/2000
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Fukagawa, Takashi, Kishigami, Takaaki, Yuda, Yasuaki, Hoshino, Masayuki
• Primary Examiner(s): PHAN, DAO LINDA
• Application Number:
  US10/817,978
• Publication Number:
  US 20040189523A1
• Time in Patent Office: 414 Days
• Field of Search: 342/417, 342/434, 342/437, 342/442, 342/445
• US Class Current: 342/417
• CPC Class Codes: G01S 3/74 Multi-channel systems specially adapted for direction-finding, i.e. having a single antenna system capable of giving simultaneous indications of the directions of different signals systems in which the directions of different signals are determined sequentially and displayed simultaneously G01S3/04, G01S3/14
• CPC Class Codes: G06F 2218/22 Source localisation; Inverse modelling

Abstract

A radio-wave arrival-direction apparatus calculates a correlation matrix of received signals by correlation calculation between antenna elements, and calculates a noise spatial eigenmatrix, of which each row or column is an eigenvector belonging to a noise eigen-space, by eigenvalue factorization of the correlation matrix. The apparatus also factorizes a matrix including a product of the noise spatial eigenmatrix and a conjugated and transposed matrix of it to an upper or lower triangular matrix, using cholesky factorization. The apparatus calculates an angle evaluation value in a predetermined angle range of an arrival-angle evaluation function using the derived upper or lower triangular matrix, and determines an arrival angle based on the calculation result. A calculation amount in a variable angle range can be thus reduced without causing accuracy degradation of arrival direction, in an algorism requiring all angle sweep for arrival angle estimation of MUSIC method or the like.

Claims

1. A radio-wave arrival-direction estimating method comprising:

(a) calculating a correlation matrix of signals received by an array antenna including a plurality of the antenna elements by correlation calculation between the antenna elements;

(b) calculating a noise spatial eigenmatrix by eigenvalue factorization of the correlation matrix, one of a row and a column of the noise spatial eigenmatrix being an eigenvector belonging to a noise eigen-space;

(c) factorizing a matrix including a product of the noise spatial eigenmatrix and a conjugated and transposed matrix of the noise spatial eigenmatrix to a product of one of an upper triangular matrix and a lower triangular matrix;

(d) calculating an evaluation value of an arrival-angle evaluation function every predetermined angle, the arrival-angle evaluation function being expressed using the one of the upper triangular matrix and the lower triangular matrix; and

(e) determining an arrival angle based on the evaluation value every predetermined angle.

2. A radio-wave arrival-direction estimating method according to claim 1 further comprising a step of unitary-transforming the correlation matrix between step (a) and step (b), when the plurality of antenna elements are arranged linearly at a constant interval.

3. A radio-wave arrival-direction estimating method comprising:

(a) calculating a correlation matrix of signals received by an array antenna including a plurality of the antenna elements by correlation calculation between the antenna elements;

(b) calculating an inverse matrix of the correlation matrix;

(c) factorizing the inverse matrix to a product of one of an upper triangular matrix and a lower triangular matrix;

(d) calculating an evaluation value of an arrival-angle evaluation function every predetermined angle, the arrival-angle evaluation function being expressed using the one of the upper triangular matrix and the lower triangular matrix; and

(e) determining an arrival angle based on the evaluation value every predetermined angle.

4. A radio-wave arrival-direction estimating method according to claim 3 further comprising a step of unitary-transforming the correlation matrix between step (a) and step (b), when the plurality of antenna elements are arranged linearly at a constant interval.

5. A radio-wave arrival-direction estimating method comprising:

(a) calculating a correlation matrix of signals received by an array antenna including a plurality of the antenna elements by correlation calculation between the antenna elements;

(b) factorizing the correlation matrix to a product of one of an upper triangular matrix and a lower triangular matrix;

(c) calculating an inverse matrix of the one of the upper triangular matrix and the lower triangular matrix;

(d) calculating an evaluation value of an arrival-angle evaluation function every predetermined angle, the arrival-angle evaluation function being expressed using the inverse matrix of the one of the upper triangular matrix and the lower triangular matrix; and

(e) determining an arrival angle based on the evaluation value every predetermined angle.

6. A radio-wave arrival-direction estimating method according to claim 5 further comprising a step of unitary-transforming the correlation matrix between step (a) and step (b), when the plurality of antenna elements are arranged linearly at a constant interval.

7. A radio-wave arrival-direction estimating method comprising:

(a) calculating a correlation matrix of signals received by an array antenna including a plurality of the antenna elements by correlation calculation between the antenna elements;

(b) factorizing the correlation matrix to a product of one of an upper triangular matrix and a lower triangular matrix;

(c) calculating an evaluation value of an arrival-angle evaluation function every predetermined angle, the arrival-angle evaluation function being expressed using the one of the upper triangular matrix and the lower triangular matrix; and

(e) determining an arrival angle based on the evaluation value every predetermined angle.

8. A radio-wave arrival-direction estimating method according to claim 7 further comprising a step of unitary-transforming the correlation matrix between step (a) and step (b), when the plurality of antenna elements are arranged linearly at a constant interval.

9. A radio-wave arrival-direction estimating method comprising:

(a) calculating a correlation vector of signals received by an array antenna including a plurality of the antenna elements by correlation calculation between a reference antenna element and another antenna element;

(b) unitary-transforming the correlation matrix when the plurality of antenna elements are arranged linearly at a constant interval;

(c) calculating an evaluation value of an arrival-angle evaluation function every predetermined angle, the arrival-angle evaluation function being expressed using the correlation vector; and

(d) determining an arrival angle based on the evaluation value every predetermined angle.