Global positioning system receiver capable of functioning in the presence of interference

An apparatus, comprising:

• an analog radio frequency circuit;
• an analog-to-digital converter coupled to said analog radio frequency circuit, said analog-to-digital converter providing a quantization level in excess of 2 bits;
• a digital filter coupled to said analog-to-digital converter;
• and
• a digital circuit coupled to said digital filter.

An electronic media, comprising:

• a computer program having a sequence of instructions for detecting an interfering signal including:
• tuning a band pass filter over a frequency range;
• and at each of a plurality of incremental frequencies:
• computing a set of band pass filter coefficients;
• sending said set of band pass filter coefficients to a digital filter;
• repeatedly transforming an analog-to-digital converter output having a quantization level in excess of 2 bits into a band pass filter output with said digital filter to obtain a plurality of samples;
• computing an average of said plurality of samples;
• and comparing said average to a threshold to detect peaks that exceed a threshold.

A computer program comprising computer program means adapted to perform the steps of detecting an interfering signal including:

• tuning a band pass filter over a frequency range;
• and at each of a plurality of incremental frequencies:
• computing a set of band pass filter coefficients;
• sending said set of band pass filter coefficients to a digital filter;
• repeatedly transforming an analog-to-digital converter output having a quantization level in excess of 2 bits into a band pass filter output with said digital filter to obtain a plurality of samples;
• computing an average of said plurality of samples;
• and comparing said average to a threshold to detect peaks that exceed a threshold when said program is run on a computer.

A kit for retrofitting a receiver, comprising:

• an analog radio frequency circuit;
• an analog-to-digital converter coupled to said analog radio frequency circuit, said analog-to-digital converter providing a quantization level in excess of 2 bits;
• a digital filter coupled to said analog-to-digital converter;
• and
• a digital circuit coupled to said digital filter.