Node position measuring system

• US 7,321,575 B2
• Filed: 12/05/2005
• Issued: 01/22/2008
• Est. Priority Date: 12/17/2004
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Mizugaki, Kenichi, Fujiwara, Ryosuke
• Primary Examiner(s): MILORD, MARCEAU
• Application Number:
  US11/293,215
• Publication Number:
  US 20060133271A1
• Time in Patent Office: 778 Days
• Field of Search: 370/328, 370/342, 370/400, 370/401, 370/222, 455/67.11, 455/67.13, 342/457, 342/357.01, 342/357.17, 342/463
• US Class Current: 370/328
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence

Abstract

A node position measuring system according to this invention includes a node, a reference station, base stations, a server that calculates a position of the node, and a network. The reference station includes a positioning signal reception module and a reference signal generation module that transmits a reference signal after the positioning signal reception module receives the positioning signal. Each of the base stations includes a signal reception module, a reception time measuring module that detects specific patterns from the positioning signal and the reference signal received by the signal reception module to measure a detection time, and a communication module that transmits time information, which is generated from the time measured by the reception time measuring module, to the server. The server includes a position calculation module that calculates the position of the node based on the time information transmitted from the base station.

Claims

1. A node position measuring system, comprising:

a node that transmits a positioning signal;

a reference station that transmits a reference signal;

a plurality of base stations that receive the positioning signal and the reference signal;

a server that calculates a position of the node; and

a network that interconnects the base stations and the server, wherein;

the reference station comprises;

a positioning signal reception module that receives the positioning signal; and

a reference signal generation module that transmits the reference signal after the positioning signal reception module receives the positioning signal;

each of the base stations comprises;

a signal reception module that receives the positioning signal and the reference signal;

a reception time measuring module that detects specific patterns from the positioning signal and the reference signal received by the signal reception module to measure a detection time; and

a communication module that transmits time information to the server, the time information being generated from the detection time measured by the reception time measuring module; and

the server comprises a position calculation module that calculates the position of the node based on the time information transmitted from the base station.

2. The node position measuring system according to claim 1, wherein the reference station comprises:

a reception time measuring module that detects the specific pattern from the positioning signal received by the positioning signal reception module to measure a detection time; and

a communication module that transmits the time information to the server, the time information being generated from the detection time measured by the reception time measuring module.

3. The node position measuring system according to claim 1, wherein a UWB signal is used as the positioning signal and the reference signal.

4. The node position measuring system according to claim 1, wherein the specific pattern detected by the reception time measuring module indicates an end of a preamble contained in the positioning signal.

5. The node position measuring system according to claim 1, wherein:

the signal reception module receives the positioning signal containing data transmitted from the node to the base station; and

the reception time measuring module comprises;

a detection module that detects the specific patterns from the positioning signal and the reference signal received by the signal reception module; and

a counter module that measures a time when the detection module detects the specific patterns.

6. A radio base station in node position measuring system for measuring a position of a node that transmits a positioning signal, comprising:

a signal reception module that receives the positioning signal from the node and a reference signal transmitted from a reference station receiving the positioning signal;

a reception time measuring module that detects specific patterns from the positioning signal and the reference signal received by the signal reception module to measure a detection time; and

a communication module that transmits time information to a position calculation module, the time information being generated from the detection time measured by the reception time measuring module, the position calculation module calculating a position of the node based on the time information.

7. The radio base station according to claim 6, further comprising a reception signal generation module that transmits the reference signal after the signal reception module receives the positioning signal.

8. The radio base station according to claim 6, wherein a UWB signal is used as the positioning signal and the reference signal.

9. The radio base station according to claim 6, wherein the specific pattern detected by the reception time measuring module indicates an end of a preamble contained in the positioning signal.

10. The radio base station according to claim 6, wherein:

the signal reception module receives the positioning signal containing data transmitted from the node to the base station; and

the reception time measuring module comprises;

a detection module that detects the specific patterns from the positioning signal and the reference signal received by the signal reception module; and

a counter module that measures a time when the detection module detects the specific patterns.

11. A position measuring method of measuring a position of a node by using a node position measuring system, the measuring system comprising a node that transmits a positioning signal, a reference station that transmits a reference signal, base stations that receive the positioning signal and the reference signal, a server that calculates the position of the node, and a network that interconnects the base stations and the server,

the position measuring method comprising:

receiving the positioning signal at the reference station;

transmitting the reference signal from the reference station after the reception of the positioning signal;

receiving the positioning signal and the reference signal at each of the base stations;

detecting specific patterns from the received positioning signal and the reference signal at the base station;

measuring a time of detecting the specific patterns at the base station;

transmitting time information from the base station to the server, the time information being generated from the measured time; and

calculating the position of the node at the server based on the time information transmitted from the base station.

12. The position measuring method according to claim 11, further comprising:

detecting the specific pattern from the positioning signal at the reference station;

measuring the time of detecting the specific pattern at the reference station; and

transmitting the time information from the reference station to the server, the time information being generated from the measured time.

13. The position measuring method according to claim 11, wherein a UWB signal is used as the positioning signal and the reference signal.

14. The position measuring method according to claim 11, wherein the specific pattern indicates an end of a preamble contained in the positioning signal.