Method and apparatus for reducing time to first fix (TTFF) of GNSS receiver without accurate time information
AssigneeMediatek Inc.
InventorChien-Liang Tsai
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Abstract
A method for reducing Time To First Fix (TTFF) of a Global Navigation Satellite System (GNSS) receiver includes storing ephemeris information into a non-volatile memory, and utilizing the ephemeris information to determine a GNSS time, in order to reduce the TTFF. An apparatus for reducing TTFF of a GNSS receiver includes a storage module and a processing module coupled to the storage module. The storage module is utilized for storing data, wherein the stored data in the storage module is non-volatile. The processing module stores ephemeris information into the storage module and utilizes the ephemeris information to determine a GNSS time, in order to reduce the TTFF.
Claims20
A method for reducing Time To First Fix (TTFF) of a Global Navigation Satellite System (GNSS) receiver, comprising:
- storing ephemeris information into a non-volatile memory before powering down the GNSS receiver;
- and
- utilizing the ephemeris information to determine a GNSS time without referencing a real time clock (RTC), in order to reduce the TTFF when resuming the GNSS receiver.
An apparatus for reducing Time To First Fix (TTFF) of a Global Navigation Satellite System (GNSS) receiver, comprising:
- a storage module for storing data, wherein the stored data in the storage module is non-volatile;
- and
- a processing module, coupled to the storage module, for storing ephemeris information into the storage module before powering down the GNSS receiver, and utilizing the ephemeris information to determine a GNSS time without referencing a real time clock (RTC), in order to reduce the TTFF when resuming the GNSS receiver.
A method for reducing Time To First Fix (TTFF) of a Global Navigation Satellite System (GNSS) receiver, comprising:
- storing at least one timestamp with optional position information into the non-volatile memory before powering down the GNSS receiver;
- and
- when resuming the GNSS receiver, tracking GNSS satellites to decode a new value of Time Of Week (TOW), deriving an old value of TOW from the timestamp, and making a guess of a new value of Week Number (WN) according to the new value of TOW and the old value of TOW when the new value of WN is not decoded.
An apparatus for reducing Time To First Fix (TTFF) of a Global Navigation Satellite System (GNSS) receiver, comprising:
- a storage module for storing data, wherein the stored data in the storage module is non-volatile;
- and
- a processing module, coupled to the storage module, for storing ephemeris information into the storage module before powering down the GNSS receiver, and utilizing the ephemeris information to determine a GNSS time, in order to reduce the TTFF when resuming the GNSS receiver;
- wherein the processing module further stores position information with at least one timestamp into the storage module;
- and after a power-on or restart, the processing module tracks GNSS satellites to decode a new value of Time Of Week (TOW), derives an old value of TOW from the timestamp, and makes a guess of a new value of Week Number (WN) according to the new value of TOW and the old value of TOW when the new value of WN is not decoded.
Dependencies are inferred from the claim text.