Method and apparatus for saving power during synthetic positioning in GNSS receivers

1. A device comprising:

a Global Navigation Satellite System (GNSS) receiver;

an inertial sensor block; and

a processor configured to:

monitor measurement of a signal strength received by the GNSS receiver;

determine that the device enters a dead zone where the GNSS receiver is incapable of determining a position of the device, when the signal strength falls below a predetermined threshold;

disable the GNSS receiver when the device enters the dead zone; and

perform navigation functions using data from the inertial sensor block and a remotely located database while the device is in the dead zone.

2. The device of claim 1 , wherein the device further comprises a communications block for communicating data with the remotely located database.

3. The device of claim 1 , wherein the navigation functions are performed using polynomial curve fitting.

4. The device of claim 3 , wherein the data required for the polynomial curve fitting is retrieved from the remotely located database.

5. The device of claim 1 , wherein the inertial sensor block includes at least one of an accelerometer, a gyroscope, a magnetometer, a temperature sensor and a barometric pressure sensor.

6. The device of claim 5 , wherein at least one of the accelerometer, the gyroscope, the magnetometer, the temperature sensor and the barometric pressure sensor are microelectromechanical systems (MEMS) devices.

7. The device of claim 1 , wherein the GNSS receiver is enabled when the device exits the dead zone.

8. The device of claim 1 , wherein the dead zone is one of a tunnel, an urban canyon and a building.

9. A device comprising:

a Global Navigation Satellite System (GNSS) receiver; and

a processor configured to:

monitor measurement of a signal strength received by the GNSS receiver;

determine that the device enters a dead zone where the GNSS receiver is incapable of determining a position of the device, when the signal strength falls below a predetermined threshold

disable the GNSS receiver when the device enters the dead zone; and

perform navigation functions using data from a remotely located database, a recorded dead zone entry velocity, and time, while in the dead zone.

10. A method comprising the steps of:

receiving, at a processor of a device, signals from a GNSS receiver;

receiving, at the processor, inertial sensor data from an inertial sensor block;

monitoring measurement of a signal strength received by the GNSS receiver;

determining, by the processor, that the device enters a dead zone where the GNSS receiver is incapable of determining a position of the device, when the signal strength falls below a predetermined threshold;

disabling, by the processor, the GNSS receiver when the device enters the dead zone; and

performing, by the processor, navigation functions using data from the inertial sensor block and a remotely located database while in the dead zone.

11. The method of claim 10 , further comprising communicating data from the GNSS receiver or the inertial sensor block to the remotely located database over a network.

12. The method of claim 10 , wherein the navigation functions are performed using polynomial curve fitting.

13. The method of claim 12 , wherein the data required for the polynomial curve fitting is retrieved from the remotely located database.

14. The method of claim 10 , wherein the inertial sensor block includes at least one of an accelerometer, a gyroscope, a magnetometer, a temperature sensor and a barometric pressure sensor.

15. The method of claim 14 , wherein at least one of the accelerometer, the gyroscope, the magnetometer, the temperature sensor and the barometric pressure sensor are microelectromechanical systems (MEMS) devices.

16. The method of claim 10 , wherein the GNSS receiver is enabled when the device exits the dead zone.

17. The method of claim 11 , wherein the remotely located database comprises inertial sensor data or GNSS data provided by a plurality of devices.

18. The method of claim 10 , wherein the dead zone is one of a tunnel, an urban canyon and a building.