Infrastructure-aiding for satellite navigation receiver and method

• US 6,473,030 B1
• Filed: 02/28/2001
• Issued: 10/29/2002
• Est. Priority Date: 02/28/2001
• Status: Expired due to Term

• Current Assignee: Furuno Electric Co, Ltd, Seiko Epson Corporation (Seiko Group)
• Original Assignee: eRide, Inc. (Furuno Electric Co, Ltd), Seiko Epson Corporation (Seiko Group)
• Inventors: Woo, Arthur N., McBurney, Paul W.
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US09/797,521
• Publication Number:
  US 20020167441A1
• Time in Patent Office: 608 Days
• Field of Search: 342/357.09, 342/357.1, 342/357.02, 342/357.03, 455/456, 701/214, 701/215
• US Class Current: 342/357.43
• CPC Class Codes: G01C 21/206 specially adapted for indoor navigation
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• CPC Class Codes: G01S 19/29 carrier including Doppler, related G01S19/246 takes precedence
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308

Abstract

A navigation system comprises a cell-phone, a base cellular telephone site, and a webserver. Each is paired with a GPS receiver. The GPS receiver associated with the cell-phone is aided with information received from the cell-site and webserver that help reduce satellite search uncertainty. Time difference and/or frequency difference measurements are taken with data collected from what the cell-phone and its GPS receiver assume to be accurate time and frequency. Correction information is used in post-processing of the velocity solutions computed by the cell-phone to arrive at more precise determinations for the system.

Claims

1. A satellite-navigation system, comprising,

a first satellite-navigation receiver that provides for a first position solution;

a first wireless communications device collocated with the first satellite-navigation receiver and connected to share at least one of time and frequency measurements with the first satellite-navigation receiver;

a second satellite-navigation receiver for providing an accurate time and frequency estimate;

a second wireless communications device collocated with the second satellite-navigation receiver and able to make radio contact with the first wireless communications device; and

a webserver for post-processing of said first position solution with said accurate time and frequency estimate and for extracting a more accurate second position solution for the first satellite-navigation receiver, and connected by a data network to the second satellite-navigation receiver and second wireless communications device.

2. The system of claim 1, wherein:

the second satellite-navigation receiver and second wireless communications device are at a fixed location and a local differential correction measurement is obtained and communicated to the webserver for providing increased accuracy position solutions for the first satellite-navigation receiver.

3. The system of claim 1, wherein:

the webserver provides information to the first satellite-navigation receiver that reduces at least one of local-oscillator frequency uncertainty and time uncertainty, and provides for improved satellite search times and sensitivity.

4. The system of claim 3, wherein:

the webserver computes time-difference information by comparing time measurements between the first and second satellite-navigation receiver as communicated over a radio contact and said data network.

5. The system of claim 3, wherein:

the webserver computes frequency-difference information by comparing carrier frequency measurements between the first and second wireless communication devices, and such measurements are communicated over a radio contact and said data network.

11. The system of claim 3, wherein:

the webserver collects temperature measurement (tempMeas) observables and stores them in a database from which it later builds a temperature-frequency model used to improve receiver sensitivity and acquisition performance in a software-compensated-crystal-oscillator (SCXO).

12. The system of claim 1, wherein:

a minimum of one GPS satellite and three cell site base stations are used in a dual mode system configuration.

13. The system of claim 3, wherein:

the webserver includes a global positioning system (GPS) digital signal processor (DSP) application specific integrated circuit (ASIC) that integrates time-difference, frequency-difference, and temperature-measurement infrastructure-information for improved satellite acquisition and receiver sensitivity.

14. The system of claim 1, wherein:

position-solution calculations are distributed amongst the webserver and the wireless communications devices.

6. A satellite-navigation system, comprising,

a first satellite-navigation receiver that provides for a user position solution;

a cell-phone collocated with the first satellite-navigation receiver and connected to share time and frequency measurements with the first satellite-navigation receiver;

a second satellite-navigation receiver for providing an accurate time and frequency estimate;

a base cellular telephone site collocated with the second satellite-navigation receiver and able to make radio contact with the cell-phone; and

a webserver for post-processing of said user position solution with said accurate time and frequency estimate and for extracting a more accurate second position solution for the first satellite-navigation receiver, and connected by a data network to the second satellite-navigation receiver and base cellular telephone site.

7. The system of claim 6, wherein:

the second satellite-navigation receiver and base cellular telephone site are at a fixed location and a local differential correction measurement is obtained and communicated to the webserver for providing increased accuracy position solutions for the first satellite-navigation receiver.

8. The system of claim 6, wherein:

the webserver provides information to the first satellite-navigation receiver that reduces at least one of local-oscillator frequency uncertainty and time uncertainty, and provides for improved satellite search times and sensitivity.

9. The system of claim 8, wherein:

the webserver computes time-difference information by comparing time measurements between the first and second satellite-navigation receiver as communicated over a cellular radio contact and said data network.

10. The system of claim 8, wherein:

the webserver computes frequency-difference information by comparing carrier frequency measurements between cellular telephone devices, and such measurements are communicated over a cellular radio contact and said data network.

15. A satellite-navigation system, comprising,

a first satellite-navigation receiver that provides for a first position solution;

a first cell-phone collocated with the first satellite-navigation receiver and connected to make and share at least one of time and frequency measurements made with the aid of the first satellite-navigation receiver;

a second satellite-navigation receiver for providing an accurate time and frequency estimate;

a second cell-phone collocated with the second satellite-navigation receiver and able to make a telephone connection with the first cell-phone through a cellular base station located in the area; and

a webserver with telephone access to each of the cell-phones via the cellular base station, and for post-processing of said first position solution with said accurate time and frequency estimate and for extracting a more accurate second position solution for the first satellite-navigation receiver, and connected by a data network to the second satellite-navigation receiver and second cell-phone;

wherein, the first satellite-navigation receiver and first cell-phone are permanently parked at a stationary location and are continually accessible to the webserver.

16. A navigation system comprises a cell-phone, a base cellular telephone site, and a webserver, wherein each are paired with a global positioning system (GPS) receiver;

wherein, a GPS receiver associated with the cell-phone is aided with information received from the cell-site and webserver that help reduce satellite search uncertainty with time-difference and/or frequency-difference measurements taken with data collected using local cell-phone and GPS receiver time and frequency; and

wherein, correction information is used in post-processing of any velocity solutions computed by the cell-phone.