Power savings technique for a positioning system receiver

A receiver comprising:

• a plurality of correlation segments, each of the correlation segments including
• a correlation unit configured to determine correlation measures associated with a first signal and a second signal, and
• a combiner configured to receive and combine outputs of the correlation unit with outputs of the correlation unit of another of the plurality of correlation segments;
• a storage unit for each correlation segment, each storage unit coupled to store data corresponding to outputs of the combiner of the corresponding correlation segment;
• and
• a control unit configured to control access to the storage units of the correlation segments during a sequence of time intervals by allowing access to the storage unit of less than all of the plurality of correlation segments during each of the time intervals.

A receiver comprising:

• a plurality of correlation segments operable in parallel, each of the correlation segments comprising:
• correlation circuitry configured to determine correlation measures associated with a first signal and a second signal;
• and
• a combiner configured to receive and combine outputs of the correlation circuitry with outputs of the correlation circuitry of another of the plurality of correlation segments;
• and
• a storage device coupled to store data corresponding to outputs of the combiner;
• and
• control circuitry configured to store the data in the storage device of less than all of the plurality of correlation segments at a time.

A positioning system receiver including a plurality of correlation segments operable in parallel, each of the correlation segments comprising:

• correlation means for generating correlation measures of an input signal and a reference signal;
• storage means for storing data corresponding to the correlation measures;
• and
• means for accessing the storage means of only one of the correlation segments at a time, such that the storage means of a given one of the correlation segments is accessed during a time period, and the storage means of each other of the correlation segments is not accessed during the time period.

A positioning system receiver including a search stage for locating a received signal, the search stage including a plurality of correlation segments operable in parallel, each of the correlation segments comprising:

• a correlator coupled to receive an input signal and a reference signal, the correlator generating correlation measures of the input signal and the reference signal;
• an adder tree coupled to receive the correlation measures;
• a summer coupled to the output of the adder tree and to the output of the adder tree of at least one other of the plurality of correlation segments and outputting a summation thereof;
• and
• a plurality of accumulators coupled to the output of the summer.

A global positioning system (GPS) receiver including a search stage for locating a received signal, the search stage including a plurality of correlation segments operable in parallel, each of the correlation segments comprising:

• a correlator coupled to receive an input code and a reference code, the correlator generating correlation measures of the input code and the reference code for bit sequences m bits in length;
• an adder tree coupled to receive the correlation measures;
• a summer coupled to the output of the adder tree and to the output of the adder tree of at least one other of the plurality of correlation segments and outputting a summation thereof;
• a plurality of coherent accumulators coupled to the output of the summer, each of the coherent accumulators including m storage locations;
• and
• control circuitry configure to cause the coherent accumulators of only one of the correlation segments to be accessed at a time, such that all m storage locations in the coherent accumulators of a given one of the correlation segments are accessed during a time period, and the coherent accumulators of all others of the correlation segments are not accessed during the time period.

A positioning system receiver including a search stage for locating a received signal, the search stage comprising:

• a first correlation segment including:
• a first correlator coupled to receive a first input signal and a reference signal, the first correlator generating correlation measures of the input signal and the reference signal;
• a first adder tree coupled to receive the correlation measures;
• a first summer coupled to receive the output of the first adder tree;
• and
• a first plurality of accumulators coupled to the output of the first summer;
• and
• a second correlation segment operable in parallel with the first correlation segment and including:
• a second correlator coupled to receive a second input signal and the reference signal, the second correlator generating correlation measures of the second input signal and the reference signal;
• a second adder tree coupled to receive the correlation measures of the second input signal and the reference signal;
• a second summer coupled to receive the output of the second adder tree and the output of the first adder tree, wherein the first summer is further coupled to receive the output of the second adder tree;
• and
• a second plurality of accumulators coupled to the output of the second summer.

A method of operating a signal receiver, the signal receiver including a plurality of correlation segments operable in parallel, each of the correlation segments having a separate plurality of storage locations associated therewith, the method comprising:

• in each of the plurality of correlation segments,
• generating correlation data associated with a plurality of signals and
• combining correlation data generated in the correlation segment with correlation data generated in each other correlation segment, to form data to be stored in the storage locations of the correlation segment;
• and
• storing the correlation data during each of a plurality of time intervals by accessing the storage locations of less than all of the plurality of correlation segments during each of the plurality of time intervals.

A method of operating a positioning system receiver for low power consumption, the positioning system receiver including a first correlation segment and a second correlation segment operable in parallel, the first correlation segment including a first set of accumulators, the second correlation segment including a second set of accumulators, the method comprising:

• (a) in each of the first and second correlation segments, generating correlation data associated with an input signal and a reference signal;
• (b) in the first correlation segment, combining correlation data generated in the first correlation segment with correlation data generated in the second correlation segment;
• (c) in the second correlation segment, combining the correlation data generated in the second correlation segment with the correlation data generated in the first correlation segment;
• (d) storing the correlation data combined in the first correlation segment in the first set of accumulators during a first time period, during which the second set of accumulators are not allowed to be accessed;
• and
• (e) storing the correlation data combined in the second correlation segment in the second set of accumulators during a second time period, during which the first set accumulators are not allowed to be accessed.