Method and apparatus for acquiring satellite positioning system signals

A satellite positioning system (SPS) receiver comprising:

• an SPS antenna which is configured to receive SPS signals;
• a processor coupled to said SPS antenna, said processor determining a first pseudorange to a first SPS satellite and searching for time of arrival of SPS signals from a second SPS satellite in a range determined by an estimated pseudorange to said second SPS satellite, said estimated pseudorange being determined from an approximate location of said SPS receiver and from said first pseudorange.

A digital processing system comprising:

• a communication interface;
• a storage device;
• a processor coupled to said storage device and to said communication interface, said processor determining an approximate location of a mobile satellite positioning system (SPS) receiver which is capable of communication with said digital processing system through said communication interface and wherein said processor determines an estimated pseudorange for a first pseudorange to a first SPS satellite, said estimated pseudorange being determined from said approximate location and a satellite position of said first SPS satellite and wherein said estimated pseudorange is transmitted through said communication interface to said mobile SPS receiver.

A computer readable medium containing executable computer program instructions which, when executed by a data processing system, cause said data processing system to perform a method comprising:

• determining an approximate location of a mobile satellite positioning system (SPS) receiver;
• determining an estimated pseudorange for a first pseudorange to a first SPS satellite, said estimated pseudorange being determined from said approximate location and a satellite position of said first SPS satellite;
• transmitting said estimated pseudorange to said mobile SPS receiver.

A satellite positioning system (SPS) receiver comprising:

• an SPS antenna which is configured to receive SPS signals;
• a processor coupled to said SPS antenna, said processor determining a time of day at said SPS receiver to an accuracy of better than a framing period of said SPS signals and searching for a time of arrival of SPS signals from an SPS satellite in a range determined by an estimated pseudorange to said SPS satellite, said estimated pseudorange being determined from an approximate location of said SPS receiver and from a satellite position data and from said time of day.

A satellite positioning system (SPS) receiver comprising:

• an SPS antenna which is configured to receive SPS signals;
• a processor coupled to said SPS antenna, said processor determining a time of day at said SPS receiver and searching for time of arrival of SPS signals from an SPS satellite in a range determined by an estimated pseudorange to said SPS satellite, said estimated pseudorange being determined from said time of day and from a set of mathematical descriptions of estimated ranges versus time, said estimated ranges being from said SPS receiver to said SPS satellites viewable by said SPS receiver.

A digital processing system comprising:

• a communication interface;
• a storage device;
• a processor coupled to said storage device and to said communication interface, said processor determining an approximate location of a mobile satellite positioning system (SPS) receiver which is capable of communication with said digital processing system through said communication interface and wherein said processor determines a set of mathematical descriptions of estimated ranges versus time, said estimated ranges being from said SPS receiver to said SPS satellites viewable by said SPS receiver, said set of mathematical expressions being determined from said approximate location and wherein said set of mathematical expressions is transmitted through said communication interface to said mobile SPS receiver.

A computer readable medium containing executable computer program instructions which, when executed by a data processing system, cause said data processing system to perform a method comprising:

• determining an approximate location of a mobile satellite positioning system (SPS) receiver;
• determining a set of mathematical descriptions of estimated ranges versus time, said estimated ranges being from said SPS receiver to SPS satellites viewable by said SPS receiver, said set of mathematical descriptions being determined from said approximate location;
• transmitting said set of mathematical descriptions to said mobile SPS receiver.