System and method for dynamically estimating output variances for carrier-smoothing filters

A receiver system, comprising:

• a preamplifier unit;
• a down-converter unit, an input of said down-converter unit coupled to an output of said preamplifier unit;
• an analog-to-digital conversion unit, an input of said analog-to-digital conversion unit coupled to an output of said down-converter unit;
• a processing unit, said processing unit coupled to an output of said analog-to-digital conversion unit;
• and at least one smoothing filter, a plurality of inputs of said at least one smoothing filter coupled to said processing unit, said processing unit operable to:
• define a current output term of said at least one smoothing filter;
• determine a total variance of said at least one smoothing filter;
• determine a variance of said current output term of said at least one smoothing filter;
• incrementally calculate said variance of said current output term of said at least one smoothing filter;
• derive a steady-state variance for an output of said at least one smoothing filter;
• and
• redefine said steady-state variance as a function of a variance of an input pseudorange value (ρ) and a variance of an input accumulated carrier phase value (∅ACC) of said at least one smoothing filter.

A navigation receiver, comprising:

• means for preamplifying a received signal;
• means for converting a preamplified signal from a radio frequency to an intermediate frequency, said means for converting coupled to an output of said means for preamplifying;
• means for converting an analog signal received from said means for converting to a digital form;
• smoothing means;
• and
• processing means coupled to said smoothing means, for defining a current output term for said smoothing means, determining a total variance term for said smoothing means, determining a variance of said current output term, of said smoothing means, incrementally calculating said variance of said current output term of said smoothing means, deriving a steady-state variance for an output of the smoothing mean, and redefining said steady-state variance as a function of a variance of an input pseudorange value(ρ) and a variance of an input accumulated carrier phase value (∅ACC) of the smoothing means.

A computer program product, comprising:

• a computer-usable medium having computer-readable code embodied therein for configuring a computer processor, the computer program product comprising:
• a first executable computer-readable code configured to cause a computer processor to define a current output term for a smoothing filter;
• a second executable computer-readable code configured to cause a computer processor to determine a total variance of said smoothing filter;
• a third executable computer-readable code configured to cause a computer processor to determine a variance of said current output term of said smoothing filter;
• a fourth executable computer-readable code configured to cause a computer processor to incrementally calculate said variance of said current output term of said smoothing filter;
• a fifth executable computer-readable code configured to cause a computer processor To derive a steady-state variance for an output of the smoothing filter;
• and
• a sixth executable computer-readable code configured to cause a computer processor to redefine said steady-state variance as a function of a variance of an input pseudorange value (ρ) and a variance of an input accumulated carrier phase value (∅ACC) of the smoothing filter.