Methods and apparatuses for processing of global positioning system signals with a matched filter

A method for processing substantially concurrently at least two different Satellite Positioning System (SPS) signals, said method comprising:

• determining a first set of pseudonoise (PN) coefficients corresponding to a first SPS signal;
• processing said first SPS signal in a matched filter with a first set of PN coefficients during a first window of time;
• determining a second set of PN coefficients corresponding to a second SPS signal;
• and
• processing said second SPS signal in said matched filter with said second set of PN coefficients during a second window of time;
• wherein said first and said second windows of time occur within a period of time not greater than one SPS frame period.

A circuit for substantially concurrently processing at least two Doppler frequencies of a Satellite Positioning System (SPS) signal, said circuit comprising:

• an input circuit for receiving said SPS signal;
• a data shift register coupled to said input circuit, said data shift register storing said SPS signal;
• a matched filter circuit coupled to said data shift register, said matched filter circuit computing an output based on said SPS signal;
• a pseudonoise (PN) weight generation circuit having an output, said PN weight generation circuit determining a set of PN coefficients corresponding to said SPS signal;
• a PN data shift register having an input which is coupled to said output of said PN weight generation circuit and having an output which is coupled to a first input of said matched filter circuit;
• a frequency coefficient generation circuit having an output, said frequency coefficient generation circuit determining a first set of frequency coefficients during a first interval of time and a second set of frequency coefficients during a second interval of time, wherein said first interval of time and said second interval of time occur within a time period no greater than one SPS frame period;
• a frequency data shift register having an input which is coupled to said output of said frequency coefficient generation circuit and having an output which is coupled to a second input of said matched filter circuit;
• a storage circuit coupled to an output of said matched filter circuit, said storage circuit to store in a first set of memory locations a first output of said matched filter circuit corresponding to said first set of frequency coefficients during a third interval of time, and said storage circuit to store in a second set of memory locations a second output of said matched filter circuit corresponding to said second set of frequency coefficients during a fourth interval of time, wherein said third interval of time and said fourth interval of time occur within a time period no greater than one SPS frame period.

A circuit for substantially concurrently processing at least two Satellite Positioning System (SPS) signals each having a distinct PN spreading code, said circuit comprising:

• an input circuit for receiving said SPS signal;
• a data shift register coupled to said input circuit, said data shift register storing said SPS signal;
• a matched filter circuit coupled to said data shift register to receive said SPS signal and to process said SPS signal;
• a pseudonoise (PN) weight generation circuit having an output, said PN weight generation circuit determining a first set of PN coefficients corresponding to a first SPS signal during a first interval of time and determining a second set of PN coefficients corresponding to a second SPS signal during a second interval of time;
• wherein said first interval of time and said second interval of time occur within a time period no greater than one SPS frame period;
• a PN data shift register having an input which is coupled to said output of said PN weight generation circuit and having an output which is coupled to a first input of said matched filter circuit;
• a storage circuit coupled to an output of said matched filter circuit, said storage circuit to store in a first set of memory locations a first output of said matched filter circuit corresponding to said first set of PN coefficients during a third interval of time, and to store in a second set of memory locations a second output of said matched filter corresponding to said second set of PN coefficients during a fourth interval of time, wherein said third interval of time and said fourth interval of time occur within a time period no greater than one SPS frame period.