# US 2010/0164780 A1 · Event detecting apparatus

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- Number: US 2010/0164780 A1
- Document ID: US20100164780A1
- Status: Published application
- Kind: A1
- Application number: 12/449,964
- Filed: 2008-02-29
- Published: 2010-07-01
- Earliest claimed: 2007-03-06
- Assignees: Keio University
- Inventors: Tomoaki Ohtsuki; Hiroyuki Tsuji; Shouhei Ikeda
- Web page: https://patentgrep.com/patent/US20100164780A1

## CPC

- H04B 7/0413: MIMO systems
- G01S 13/0209: {Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband}
- G01S 13/56: for presence detection {(presence detection using near field arrangements G01V3/00, e.g. G01V3/08, G01V3/12; burglar, theft or intruder alarms with electrical actuation G08B13/22 - G08B13/26)}
- G01S 13/886: {for alarm systems (alarms with electrical actuation G08B13/22)}
- H04B: TRANSMISSION
- G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES

## Abstract

An event detecting apparatus capable of high-precision detection of an event even by use of a narrow-band signal comprises: a plurality of antennas 21 that receive radio waves transmitted from a transmitter, a correlation matrix operation unit 22 that expresses signals received by the plurality of antennas 21 as received vectors, to operate a correlation matrix on the basis of the received vectors, an eigenvector operation unit 23 that performs eigenvalue expansion of the correlation matrix operated by the correlation matrix operation unit 22, to operate eigenvectors covering a signal subspace, and an event detecting unit 24 that detects a temporal change in the eigenvectors operated by the eigenvector operation unit 23, to detect an event.

## Claims

### Claim 1

An event detecting apparatus comprising:
a plurality of antennas for receiving radio waves transmitted from a transmitter;
a correlation matrix operation unit for operating a correlation matrix from a received vector with signals received by the plurality of antennas as the received vector;
an eigenvector operation unit for operating an eigenvector which covers a signal subspace by eigenvalue expansion of the correlation matrix operated by the correlation matrix operation unit; and
an event detecting unit for detecting an event by detecting a temporal change of the eigenvector operated by the eigenvector operation unit.

### Claim 2 (depends on 1)

The event detecting apparatus according to claim 1, wherein the plurality of antennas are an array antenna.

### Claim 3 (depends on 1)

The event detecting apparatus according to claim 1, wherein the eigenvector operation unit operates an eigenvector corresponding to a maximum eigenvalue of the correlation matrix.

### Claim 4 (depends on 2)

The event detecting apparatus according to claim 2, wherein the eigenvector operation unit operates an eigenvector corresponding to a maximum eigenvalue of the correlation matrix.

### Claim 5 (depends on 1)

The event detecting apparatus according to claims 1, wherein the event detecting unit compares an inner product of the eigenvector during normal time and the eigenvector during observation with a predetermined threshold value.

### Claim 6 (depends on 2)

The event detecting apparatus according to claims 2, wherein the event detecting unit compares an inner product of the eigenvector during normal time and the eigenvector during observation with a predetermined threshold value.

### Claim 7 (depends on 3)

The event detecting apparatus according to claims 3, wherein the event detecting unit compares an inner product of the eigenvector during normal time and the eigenvector during observation with a predetermined threshold value.