Wave arrival direction estimating method and antenna apparatus having wave arrival direction estimating function

• US 6,377,213 B1
• Filed: 12/28/1999
• Issued: 04/23/2002
• Est. Priority Date: 12/28/1998
• Status: Expired due to Term

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Bushiki Kaisha Toshiba
• Inventors: Shoki, Hiroki, Odachi, Noriaki
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/472,809
• Time in Patent Office: 847 Days
• Field of Search: 342/380, 342/383, 342/372, 342/373, 342/374
• US Class Current: 342/383
• CPC Class Codes: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured
• 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: H01Q 25/002 providing at least two patterns of different beamwidth; Variable beamwidth antennas

Abstract

A method for estimating an arrival direction of an electromagnetic wave by the BS-MUSIC, by inputting into one receiver arrival wave reception signals received by a plurality of antenna elements constituting an array antenna. At first, a wide range is scanned in a plurality of directions with a wide antenna beam and a first estimation of arrival direction is carried out. Next, a plurality of directions are scanned with a narrow antenna beam to cover only the directions obtained as a result of the first estimation of arrival direction. Thus, a second estimation of arrival direction is carried out. With this arrangement, it is possible to provide a method of estimating an arrival direction by using a small number of receivers in a small apparatus at low cost. Further, based on this method, it is also possible to estimate an arrival direction in a small calculation volume even under the unknown environment of waves.

Claims

1. A wave arrival direction estimating method for receiving reception signals from a plurality of antenna elements with one receiver, and estimating arrival directions of electromagnetic waves based on antenna beams formed of the reception signals, the method comprises:

first estimation of arrival direction by using first antenna beams; and

second estimation of arrival direction in detail by using second antenna beams each of which is narrower than each of the first antenna beams and directed to estimated directions by the first estimation.

2. The wave arrival direction estimating method according to claim 1, further comprising:

third estimation of arrival direction in further detail by using third antenna beams each of which is narrower than each of the second beams, and directed to estimated directions by the second estimation.

3. The wave arrival direction estimating method according to claim 1, wherein said first estimation is carried out by scanning the first antenna beams and said second estimation is carried out by scanning the second antenna beams.

4. The wave arrival direction estimating method according to claim 1, wherein said second estimation estimates plural arrival directions simultaneously.

5. The wave arrival direction estimating method according to claim 1, wherein said first antenna beams are formed of reception signals from a first number of antenna elements and said second antenna beams are formed of reception signals from a second number of antenna elements, the second number being larger than the first number.

6. An antenna apparatus comprising:

a plurality of antenna elements;

a plurality of phase shifters configured to individually shift phases of signals output from said plurality of antenna elements;

a selector configured to select some of said plurality of antenna elements;

a synthesis circuit configured to synthesize signals output from said plurality of antenna elements selected by said selector into a synthesis signal;

a receiver configured to receive the synthesis signal from said synthesis circuit;

an arrival direction estimation circuit configured to estimate arrival directions of electromagnetic waves based on antenna beams formed of a reception signal output from said receiver; and

a controller configured to control phase shift quantities of said phase shifters and a selection operation of said selector, thereby to carry out two-stage estimation of arrival directions by sequentially using first antenna beams and then using second antenna beams each of which is narrower than each of the first antenna beams.

7. The antenna apparatus according to claim 6, wherein said controller controls said selector to select said some of the antenna elements thereby to form the first antenna beams, and controls the phase shift quantities of said phase shifters to carry out a first estimation of arrival directions by directing the first antenna beams to predetermined directions, and then, the controller controls said selector to select all of said plurality of antenna elements to form the second antenna beams, and controls the phase shift quantities of said phase shifters to carry out a second estimation of arrival directions by directing the second antenna beams to directions of a result of the first estimation of arrival direction.

8. The antenna apparatus according to claim 6, wherein said selector comprises high-frequency switches of a same number as said plurality of antenna elements, and the high-frequency switches are individually on-and-off controlled by said controller.

9. The antenna apparatus according to claim 6, wherein said selector comprises variable gain amplifiers of a same number as said plurality of antenna elements, and the variable gain amplifiers are individually on-and-off controlled by said controller.

10. The antenna apparatus according to claim 6, wherein said controller controls said selector to select a first number of antenna elements thereby to form the first antenna beams, and controls the phase shift quantities of said phase shifters to carry out a first estimation of arrival directions by directing the first antenna beams to predetermined directions, and then, the controller controls said selector to select a second number of antenna elements to form the second antenna beams, the second number being larger than the first number, and controls the phase shift quantities of said phase shifters to carry out a second estimation of arrival directions by directing the second antenna beams to directions of a result of the first estimation of arrival directions.

11. An antenna apparatus comprising:

a plurality of antenna elements configured to receive first electromagnetic waves;

a plurality of phase shifters configured to individually shift phases of signals output from said plurality of antenna elements;

a reflector configured to selectively reflect signals from some of said antenna elements and phase-shifted by said phase shifters so as to transmit second electromagnetic waves from said antenna elements;

a primary emission antenna configured to receive the second electromagnetic waves transmitted from said antenna elements;

a receiver configured to receive signals output from said primary emission antenna;

an arrival direction estimation circuit configured to estimate arrival directions of the first electromagnetic waves based on antenna beams formed of reception signals output from said receiver; and

a controller configured to control phase shift quantities of said phase shifters and a selective reflection operation of said reflector, thereby to carry out two-stage estimation of arrival directions by sequentially using first antenna beams and then using second antenna beams each of which is narrower than each of the first antenna beams.

12. The antenna apparatus according to claim 11, wherein said controller controls said reflector to select said some of the antenna elements thereby to form the first antenna beams, and controls the phase shift quantities of said phase shifters to carry out a first estimation of arrival directions by directing the first antenna beams to predetermined directions, and then, the controller controls said reflector to select all of said plurality of antenna elements to form the second antenna beams, and controls the phase shift quantities of said phase shifters to carry out a second estimation of arrival directions by directing the second antenna beams to directions of a result of the first estimation of arrival directions.

13. The antenna apparatus according to claim 11, wherein said reflector comprises high-frequency switches of a same number as said plurality of antenna elements, and the high-frequency switches are individually on-and-off controlled by said controller.

14. The antenna apparatus according to claim 11, wherein said reflector comprises variable gain amplifiers of a same number as said plurality of antenna elements, and the variable gain amplifiers are individually on-and-off controlled by said controller.

15. The antenna apparatus according to claim 11, wherein said controller controls said reflector to select a first number of antenna elements thereby to form the first antenna beams, and controls the phase shift quantities of said phase shifters to carry out a first estimation of arrival directions by directing the first antenna beams to predetermined directions, and then, the controller controls said reflector to select a second number of antenna elements to form the second antenna beams, the second number being larger than the first number, and controls the phase shift quantities of said phase shifters to carry out a second estimation of arrival directions by directing the second antenna beams to directions of a result of the first estimation of arrival directions.

16. An antenna apparatus comprising:

a plurality of antenna elements;

a plurality of distributors each configured to be supplied with a signal output from each of said plurality of antenna elements and have first to n-th output terminals;

n synthesis circuits configured to be commonly supplied with the first to n-th output signals of said plurality of distributors, each of the synthesis circuits comprising;

phase shifters configured to shift phases of signals output from said plurality of antenna elements, respectively;

a selector configured to select some of said plurality of antenna elements; and

a synthesizer configured to synthesize signals from said some of the antenna elements selected by said selector and phase-shifted by said phase shifters,

n receivers configured to be supplied with outputs of said signal synthesis circuits, respectively;

an arrival direction estimation circuit configured to estimate wave arrival directions based on antenna beams formed of reception signals output from said n receivers; and

a controller for controlling phase shift quantities of said phase shifters and a selection operation of said selector, thereby to carry out two-stage estimation of wave arrival directions by sequentially using first antenna beams and then using second antenna beams each of which is narrower than each of the first antenna beams.

17. The antenna apparatus according to claim 16, wherein said controller controls said selector to select said some of the antenna elements thereby to form the first antenna beams, and controls the phase shift quantities of said phase shifters to carry out a first estimation of arrival direction by directing the first antenna beams to a predetermined direction, and then, the controller controls said selector to select all of said plurality of antenna elements to form the second antenna beams, and controls the phase shift quantities of said phase shifters to carry out a second estimation of arrival direction by directing the second antenna beams to directions of a result of the first estimation of arrival direction.

18. The antenna apparatus according to claim 16, wherein said selector comprises high-frequency switches of a same number as said plurality of antenna elements, and the high-frequency switches are individually on-and-off controlled by said controller.

19. The antenna apparatus according to claim 16, wherein said selector comprises variable gain amplifiers of a same number as said plurality of antenna elements, and the variable gain amplifiers are individually on-and-off controlled by said controller.

20. The antenna apparatus according to claim 16, wherein said controller controls said selector to select a first number of antenna elements thereby to form the first antenna beams, and controls the phase shift quantities of said phase shifters to carry out a first estimation of arrival directions by directing the first antenna beams to predetermined directions, and then, the controller controls said selector to select a second number of antenna elements to form the second antenna beams, the second number being larger than the first number, and controls the phase shift quantities of said phase shifters to carry out a second estimation of arrival directions by directing the second antenna beams to directions of a result of the first estimation of arrival directions.

21. An antenna apparatus comprising:

antenna elements configured to receive electromagnetic waves and output reception signals;

a beam synthesis circuit configured to be supplied with the reception signals output from the antenna elements and form antenna beams;

an arrival direction estimation circuit configured to estimate arrival directions of the electromagnetic waves based on the antenna beams; and

a controller configured to control the beam synthesis circuit to sequentially form first antenna beams and then second antenna beams each of which is narrower than each of the first antenna beams, thereby said arrival direction estimation circuit carrying out two-stage estimation of the arrival directions by sequentially using the first antenna beams and then using the second antenna beams.

22. The antenna apparatus according to claim 21, wherein said beam synthesis circuit selects a first number of reception signals from the reception signals thereby to form the first antenna beams, and select a second number of reception signals from the reception signals thereby to form the second antenna beams, the second number being larger than the first number.