Position detecting system and RFID terminal

• US 20070290855A1
• Filed: 08/23/2007
• Published: 12/20/2007
• Est. Priority Date: 03/02/2005
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Sajikawa, Yasuyuki, Nagino, Hideki
• Granted Patent: US 7,746,275 B2
• Time in Patent Office: Days
• US Class Current: 340/572.1
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 4/02 Services making use of location information
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A position detecting system includes an RFID terminal configured to transmit an identification information signal by radio; a plurality of receiving devices configured to receive the identification information signal; and a position detecting server configured to receive a reception notification of the identification information signal from each of the receiving device and configured to estimate a position of the RFID terminal. The RFID terminal includes a part configured to perform radio transmission of a plurality of identification information signals having different radio strengths. The position detecting server includes a part configured to integrate the reception notifications of the identification information signals having different radio strengths and configured to estimate the position of the RFID terminal.

Claims

1. A position detecting system, comprising:

an RFID terminal configured to transmit an identification information signal by radio;

a plurality of receiving devices configured to receive the identification information signal; and

a position detecting server configured to receive a reception notification of the identification information signal from each of the receiving device and configured to estimate a position of the RFID terminal;

wherein the RFID terminal includes a part configured to perform radio transmission of a plurality of identification information signals having different radio strengths; and

the position detecting server includes a part configured to integrate the reception notifications of the identification information signals having different radio strengths and configured to estimate the position of the RFID terminal.

2. A position detecting system, comprising:

an RFID terminal configured to transmit an identification information signal by radio;

a plurality of receiving devices configured to receive the identification information signal; and

a position detecting server configured to receive a reception notification of the identification information signal from each of the receiving device and configured to estimate a position of the RFID terminal;

wherein the RFID terminal includes a part configured to perform radio transmission of a plurality of identification information signals having different radio frequencies; and

the position detecting server includes a part configured to integrate the reception notifications of the identification information signals having different radio frequencies and configured to estimate the position of the RFID terminal.

3. An RFID terminal of a position detecting system, in which the position detecting system an identification information signal transferred by radio from the RFID terminal is received by a plurality of receivers, and reception notification of the identification information signal from each of the receivers is received by a position detecting server, so that a position of the RFID terminal is estimated, the RFID terminal comprising:

a part configured to perform radio transmission of a plurality of the identification information signals having different radio strengths.

5. The RFID terminal as claimed in claim 3,

wherein the part configured to perform radio transmission of the plurality of the identification information signals having different radio strengths includes an attenuation switching part;

the attenuation switching part switches attenuation of the identification information signal formed by modulating coded ID information.

7. The RFID terminal as claimed in claim 3,

wherein the part configured to perform radio transmission of the plurality of the identification information signals having different radio strengths includes a first modulating part, a second modulating part, and a selection part;

the first modulating part modulates coded ID information so as to output one of the identification information signals having a high radio strength;

the second modulating part modulates the coded ID information so as to output another one of the identification information signals having a low radio strength; and

the selection part selects the first modulating part or the second modulating part so as to supply the coded ID information.

4. An RFID terminal of a position detecting system, in which position detecting system an identification information signal transferred by radio from the RFID terminal is received by a plurality of receivers, and reception notification of the identification information signal from each of the receivers is received by a position detecting server, so that a position of the RFID terminal is estimated, the RFID terminal comprising:

a part configured to perform radio transmission of a plurality of the identification information signals having different radio frequencies.

6. The RFID terminal as claimed in claim 4,

wherein the part configured to perform radio transmission of the plurality of the identification information signals having different radio frequencies includes a first modulating part, a second modulating part, and a selection part;

the first modulating part modulates coded ID information so as to output one of the identification information signals of a first frequency;

the second modulating part modulates the coded ID information so as to output another one of the identification information signals of a second frequency; and

the selection part selects the first modulating part or the second modulating part so as to supply the coded ID information.

8. A position detecting system, comprising:

an RFID terminal configured to transmit an identification information signal by radio;

a plurality of receiving devices configured to receive the identification information signal; and

a position detecting server configured to receive a reception notification of the identification information signal from each of the receiving devices and configured to estimate the position of the RFID terminal;

wherein the RFID terminal includes a part configured to perform radio transmission of a plurality of the identification information signals having different radio strengths and frequencies; and

the position detecting server includes a part configured to integrate the reception notifications of the identification information signals having different radio frequencies and radio strengths and configured to estimate the position of the RFID terminal.