Positioning system

• US 7,460,066 B2
• Filed: 01/25/2008
• Issued: 12/02/2008
• Est. Priority Date: 02/28/2003
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Ikeda, Masayuki
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): Mull; Fred H.
• Application Number:
  US12/011,361
• Publication Number:
  US 20080129590A1
• Time in Patent Office: 312 Days
• Field of Search: 34235706-35707, 342/357.09, 342/357.1, 342/357.14, 342/357.15, 342463-465
• US Class Current: 342/357.43
• CPC Class Codes: G01S 11/08 using synchronised clocks
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/06 employing an initial estimate of the location of the receiver as aiding data or in generating aiding data
• CPC Class Codes: G01S 19/12 wherein the cooperating elements are telecommunication base stations
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A positioning system is provided having a first signal source for originating synchronous signals, and a second signal source for originating a signal which is not synchronous with the signal from the first signal source. The system determines, based on a signal propagation time and signal propagation speed from the first or second signal source, the distance to this signal source so as to determine a position of a receiving point.

Claims

1. A positioning system for determining a position of a positioning terminal, the system including a plurality of first signal sources each emitting a respective first signal, and one or more second signal sources each emitting a respective second signal, the first signals being synchronous with a reference time and the second signals being non-synchronous with the first signals, said system determining the position of the positioning terminal based on a signal propagation time and signal propagation speed of at least one of the first and second signal sources, said positioning system comprising:

a measurement device associated with each second signal source that receives the first signals from the first signal sources to determine a position P of the measurement device and a time of measurement when the measurement device receives the first signals and for, based on the time of measurement, measuring a receiving time (TR), based on the reference time, of a predetermined event of the second signals;

a control device that determines a signal propagation time (t) between the measurement device and its associated second signal source by calculating a relative distance |P−

Q| between the measurement device and its associated second signal source based on the position P measured by the measurement device and a position Q of the second signal source and by dividing the resulting distance by the signal propagation speed, and that determines a time (TT), based on the reference time, at which the second signal source originates the predetermined event by solving TR−

t;

the positioning terminal including a receiving device that receives signals from the first and second signal sources; and

a communication device that communicates between the control device and the positioning terminal,

wherein the communication device communicates the time TT to the positioning terminal, and

wherein the positioning terminal receives the time TT from the communication device and uses the time TT to receive from among the first and second signals for determining the position of the positioning terminal.

2. The positioning system according to claim 1, wherein the first signal sources further comprise GPS satellites.

3. The positioning system according to claim 1, wherein the second signal sources further comprise base stations of a mobile communication network.

4. The positioning system according to claim 1, wherein the measurement device further comprises a mobile terminal in good condition, wherein the position P of the measurement device can be determined without accurate time information, and measures P and TR to voluntarily report the measured P and TR to the control device in the same mobile communication network.

5. The positioning system according to claim 1, wherein the measurement device further comprises a mobile terminal in good condition, where the position P of the measurement device can be determined without accurate time information, and measures P and TR according to a request from the control device in the same network to report the measured P and TR to the control device.

6. A positioning terminal for determining a position of the positioning terminal, the positioning terminal including a receiving device that receives signals from a plurality of first signal sources each emitting a respective first signal and one or more second signal sources each emitting a respective second signal, the first signals being synchronous with a reference time and the second signals being non-synchronous with the first signals, the system determining a position of the positioning terminal based on a signal propagation time and signal propagation speed of at least one of the first and second sources, said positioning terminal comprising:

a calculation device for calculating

TT=TR−

|P−

Q|/c;

wherein the P is a position of a measurement device when the measurement device received the first signals from the first signal sources;

the Q is a position of the one second signal source;

the |P−

Q| is a relative distance between the measurement device and the one second source;

the c is a signal propagation speed;

the TR is a receiving time, based on the reference time, when the measurement device received a predetermined event of the second signals at the position P;

wherein the positioning terminal uses the time TT to receive the signals from the first signal sources;

wherein the positioning terminal receives the first and second signals for determining the position of the positioning terminal.

7. The positioning terminal according to claim 6, wherein the first signal sources further comprise GPS satellites.

8. The positioning terminal according to claim 6, wherein the second signal sources further comprise base stations of a mobile communication network.

9. The positioning terminal according to claim 6:

wherein the measurement device further comprises a mobile terminal in good condition;

wherein the position P of the measurement device can be determined without accurate time information;

wherein the measurement device measures P and TR; and

wherein the measurement device voluntarily reports the measured P and TR to the control device in the same mobile communication network.

10. The positioning terminal according to claim 6, wherein the measurement device further comprises a mobile terminal in good condition, where the position P of the measurement device can be determined without accurate time information, and measures P and TR according to a request from the control device in the same network to report the measured P and TR to the control device.

11. The positioning terminal according to claim 6, wherein the second signal sources further comprise television broadcast stations.