Power conservation techniques for use in devices with selectable power modes

An apparatus for use in a device operable in a plurality of selectable power modes, the apparatus comprising:

• with said device in a higher power mode:
• means for obtaining one or more attribute values including a phase value from a signal acquired from a ground-based transmitter;
• and
• means for transitioning to a lower power mode in response to a determination that said one or more attribute values satisfy a profile test indicating that said device is within a characterized environment, wherein in said lower power mode at least a portion of a receiver used to acquire said signal is disabled and at least a portion of enabled device circuitry uses a timing circuit that is set based, at least in part, on at least said phase value.

A device operable in a plurality of selectable power modes, the device comprising:

• a receiver;
• a timing circuit;
• and
• a processing unit to, with said device in a higher power mode:
• obtain one or more attribute values including a phase value from a signal acquired via said receiver from a ground-based transmitter;
• and
• in response to a determination that said one or more attribute values satisfy a profile test indicating that said device is within a characterized environment, transition said device to a lower power mode wherein at least a portion of said receiver is disabled and at least a portion of enabled device circuitry uses said timing circuit that is set based, at least in part, on at least said phase value.

An article comprising:

• a non-transitory computer readable medium having stored therein computer implementable instructions executable by a processing unit of a device operable in a plurality of selectable power modes to:
• with said device in a higher power mode:
• obtain one or more attribute values including a phase value from a signal acquired from a ground-based transmitter;
• and
• in response to a determination that said one or more attribute values satisfy a profile test indicating that said device is within a characterized environment, transition said device to a lower power mode wherein at least a portion of a receiver used to acquire said signal is disabled and at least a portion of enabled device circuitry uses a timing circuit that is set based, at least in part, on at least said phase value.