Method and apparatus for determining position location using reduced number of GPS satellites and synchronized and unsynchronized base stations

• US 6,353,412 B1
• Filed: 10/29/1999
• Issued: 03/05/2002
• Est. Priority Date: 03/17/1998
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Soliman, Samir S.
• Primary Examiner(s): Phan, Dao
• Application Number:
  US09/430,618
• Time in Patent Office: 858 Days
• Field of Search: 342/356, 342/385, 342/387, 342/457, 455/422, 455/456, 455/457
• US Class Current: 342/387
• CPC Class Codes: G01S 13/82 wherein continuous-type signals are transmitted
• CPC Class Codes: G01S 19/071 DGPS corrections
• CPC Class Codes: G01S 19/12 wherein the cooperating elements are telecommunication base stations
• CPC Class Codes: G01S 19/235 Calibration of receiver components
• CPC Class Codes: G01S 19/25 involving aiding data received from a cooperating element, e.g. assisted GPS
• CPC Class Codes: G01S 19/41 Differential correction, e.g. DGPS [differential GPS]
• CPC Class Codes: G01S 19/46 the supplementary measurement being of a radio-wave signal type
• CPC Class Codes: G01S 2205/008 using a mobile telephone network
• CPC Class Codes: G01S 5/0054 of actual mobile position, i.e. position calculation on base station
• CPC Class Codes: G01S 5/009 Transmission of differential positioning data to mobile
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/0236 Assistance data, e.g. base station almanac
• 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
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method and apparatus for determining the position of a wireless communication device using global positioning system (GPS) satellites, base stations synchronized to GPS time and base stations that are unsynchronized with GPS time. The unsynchronized base stations are synchronized with one another. Time of arrival information is adjusted to take into account the fact that wireless communication devices that received GPS time information from a base station receive that information biased by the one-way delay that is encountered by the signal that communicates that information to the wireless communication device. In addition, time difference of arrival information for base stations that are not synchronized to GPS time allows the bias between these base stations GPS time to be eliminated.

Claims

1. A system for synchronizing time of arrival measurements made within a wireless communication device to global positioning system (GPS) time, comprising:

a) a receiver configured to receive;

i) time of arrival measurements made at the wireless communication system; and

ii) signals from an external source synchronized to GPS time, the signals received from the external source including an indication from which the amount of delay encountered by a signal transmitted between the external source and the wireless communication device can be determined; and

b) processing circuitry configured to adjust the received time of arrival measurements by an amount equal to the delay encountered by a signal transmitted between the external source and the wireless communication device.

2. The system of claim 1, wherein the indication from which the amount of delay can be determined is an indication of the amount of delay encountered by a signal making a round trip between the base station and the wireless communication device.

3. The system of claim 1, wherein the indication from which the amount of delay can be determined is a direct indication of the amount of delay encountered by a signal transmitted from the base station to the wireless communication device.

4. A system for synchronizing a wireless communication device to global positioning system (GPS) time, comprising:

a) a receiver configured to receive signals from an external source synchronized to GPS time, the signals received from the external source including an indication from which the amount of delay encountered by a signal transmitted between the external source and the receiver can be determined, and an indication of GPS time at the time the signal that includes the indication of GPS time is transmitted from the base station; and

b) time/frequency circuitry, including;

i) a clock; and

ii) processing circuitry configured to synchronize the clock to the received GPS time after adjusting the received GPS time for the delay encountered by a signal transmitted between the external source and the wireless communication device.

5. The system of claim 4, wherein the processing circuitry is further configured to determine a time of arrival (TOA) of the signals received from any source with respect to the synchronized clock.

6. The system of claim 5, further including a control processor for determining the n-dimensional position location of a wireless communication device from n time of arrival measurements, wherein the time of arrival measurements indicate the time of arrival of signals received from n satellites.

7. The system of claim 6, wherein the control processor resides within a base station transceiver subsystem.

8. The system of claim 6, wherein the control processor resides within a base station controller.

9. The system of claim 6, wherein the control processor resides within a dedicated position determination device.

10. A system for synchronizing time of arrival measurements made within a wireless communication device to global positioning system (GPS) time, comprising:

a) a receiver configured to receive signals from an external source synchronized to GPS time, the signals received from the external source including an indication from which the amount of delay encountered by a signal transmitted between the external source and the receiver can be determined, and an indication of GPS time at the time the signal that includes the indication of GPS time is transmitted from the base station; and

b) time/frequency circuitry, including;

i) a clock; and

ii) processing circuitry, coupled to the clock, configured to;

(1) determine the time of arrival of signals received by the receiver with respect to the clock; and

(2) adjust the time of arrival by an amount equal to delay encountered by a signal transmitted between the external source and the wireless communication device.