GPS TIME-AIDING AND FREQUENCY CORRECTION

• US 20170295555A1
• Filed: 06/23/2017
• Published: 10/12/2017
• Est. Priority Date: 08/12/2014
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Inventors: McCune, Timothy M., Russell, Michael E.
• Granted Patent: US 10,159,055 B2
• Time in Patent Office: Days
• CPC Class Codes: G01S 19/05 providing aiding data
• CPC Class Codes: G01S 19/256 relating to timing, e.g. time of week, code phase, timing offset
• CPC Class Codes: H04B 7/26 at least one of which is mobile
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: H04W 56/004 compensating for timing error of reception due to propagation delay
• CPC Class Codes: H04W 76/10 Connection setup

Abstract

A system and method for time-aiding an autonomous Global Positioning System device over a Bluetooth connection allows for a faster time to fix by allowing faster acquisition of time and ephemeris data. The time-aiding information may be distributed in a one-to-one manner or in a manner that allows for the synchronization of multiple devices.

Claims

1. A method for adjusting a clock in a mobile Global Positioning System (“

GPS”

) device, the method comprising;

connecting to the mobile GPS device by a mobile communications device over a Bluetooth link;

aligning, by the mobile communications device, a piconet clock of the mobile communications device with a boundary of an LTE frame received by the mobile communications device; and

transmitting, to the mobile GPS device using the Bluetooth link, time-synchronization information to synchronize a piconet clock of the mobile GPS device to the piconet clock of the mobile communications device, wherein the piconet clock of the mobile GPS device is used to provide time-aiding to a GPS receiver of the mobile GPS device.

2. The method of claim 1, wherein aligning the piconet clock of the mobile communications device further comprises a using a slot offset command to make a coarse adjustment to the piconet clock.

3. The method of claim 1, wherein aligning the piconet clock of the mobile communications device further comprises allowing the piconet clock to drift.

4. The method of claim 1, wherein the time-synchronization information comprises one or more of:

a slot offset, clock drift, and a timing message.

5. The method of claim 1, wherein aligning the piconet clock of the mobile communications device with the boundary of an LTE frame comprises communicating a frame synchronization pulse from a mobile wireless standard module of the mobile communications device to a Bluetooth host of the mobile communications device.

6. The method of claim 1, further comprising transmitting ephemeris data over the Bluetooth link from the mobile communications to the mobile GPS device.

7. The method of claim 1, wherein the time-synchronization information includes a synchronization train in a Unicast Directionless Data transmission.

8. A mobile Global Positioning System (“

GPS”

) device with time aiding, the device comprising;

a Bluetooth interface;

a GPS module configured to identify a location of the GPS device; and

a processor configured to connect the mobile GPS device to a mobile communications device via the Bluetooth link, receive time-synchronization information from the mobile communications device over the Bluetooth link, wherein the time synchronization information comprises information associated with a piconet clock of the mobile communications device, and adjust a piconet clock of the mobile GPS device based on the received time-synchronization information.

9. The mobile GPS device of claim 8, wherein the time-synchronization information comprises one or more of:

a slot offset, clock drift, and a timing message.

10. The mobile GPS device of claim 8, wherein the piconet clock of the mobile communications device and the piconet clock of the mobile GPS device are associated with the Bluetooth link.

11. The mobile GPS device of claim 8, wherein the mobile GPS device is a watch.

12. The mobile GPS device of claim 8, wherein the processor is further configured to receive supplemental ephemeris data from the mobile communications device over the Bluetooth link.

13. The mobile GPS device of claim 8, wherein the time-synchronization information is based on an LTE frame received at the mobile communications device.

14. A method of resolving a position of a GPS device, the method comprising:

establishing a Bluetooth connection between the GPS device and a mobile communications device;

receiving, from the mobile communications device, time-synchronization information associated with a piconet clock of the mobile communications device; and

synchronizing a piconet clock of the mobile GPS device to the piconet clock of the mobile communications device using the time-synchronization information;

wherein the piconet clock of the mobile GPS device is used to provide time-aiding to a GPS receiver of the mobile GPS device.

15. The method of claim 14, further comprising:

determining satellite ephemeris data for a plurality of terrestrial satellites at the GPS device;

establishing an absolute time reference based on the piconet clock of the mobile GPS device; and

based on the absolute time reference and satellite ephemeris data, calculating the position of the GPS device via trilateration at the GPS device.

16. The method of claim 14 wherein the time-synchronization information comprises one or more of:

a slot offset, clock drift, and a timing message.

17. The method of claim 14 wherein the mobile GPS device is a watch.

18. The method of claim 14 further comprising receiving supplemental ephemeris data from the mobile communications device over the Bluetooth link.

19. The method of claim 14 wherein the time-synchronization information is based on an LTE frame received at the mobile communications device.

20. The method of claim 14, wherein the piconet clock of the mobile communications device and the piconet clock of the mobile GPS device are associated with the Bluetooth link.