Method of cross-correlation and continuous wave interference suppression for GPS signal and associated GPS receiver
View Patent ↗A method for processing weak indoor signals in presence of cross-correlation or continuous wave interference and associated GPS receiver are provided. The method comprises providing a two-dimensional delay-Doppler accumulated power pattern having a plurality of accumulated powers corresponding to frequency and time; for a predetermined frequency, determining an average value of accumulated powers of the two-dimensional delay-Doppler accumulated power pattern over a plurality of times; and subtracting the average value from the accumulated powers used in determining the average at the frequency over the plurality of times to generate a delay-Doppler accumulated power pattern with suppressed interference effect.
1. A method for a global positioning system (GPS) receiver to suppress an to suppress an interference effect on a two-dimensional delay-Doppler accumulated power pattern, the method comprising:
providing a two-dimensional delay-Doppler accumulated power pattern comprising a plurality of accumulated powers corresponding to frequency and time;
for a predetermined frequency, determining an average value of accumulated powers of the two-dimensional delay-Doppler accumulated power pattern over a plurality of time points by excluding accumulated power value at a maximum time point and two time points adjacent to the maximum; and
subtracting the average value from the accumulated powers to generate a delay-Doppler accumulated power pattern with suppressed interference effect.
2. The method of claim 1 further comprising repeating the determining and subtracting steps for a plurality of frequencies to generate a two-dimensional delay-Doppler accumulated power pattern with suppressed interference effect.
3. The method of claim 1 , wherein the average value is obtained by calculating an arithmetic means, a medium, or a mode.
4. The method of claim 1 , wherein the average value is obtained by referencing a lookup table.
5. The method of claim 1 , wherein the predetermined frequency is a Doppler bin of the two-dimensional delay-Doppler accumulated power pattern and each time point is associated with a code bin of the two-dimensional delay-Doppler accumulated power pattern.
6. A global positioning system (GPS) receiver comprising:
an antenna;
a radio-frequency front-end coupled to the antenna;
digital signal processing circuitry coupled to the radio-frequency front-end, to output a two-dimensional delay-Doppler accumulated power pattern comprising a plurality of accumulated powers corresponding to frequency and time; and
a processor coupled to the digital signal processing circuitry to determine, for a predetermined frequency, an average value of accumulated powers of the two-dimensional delay-Doppler accumulated power pattern over a plurality of time points by excluding accumulated power values at a maximum time point and two time points adjacent to the maximum;
wherein the processor generates a delay-Doppler accumulated power pattern with suppressed interference effect by subtracting the average value from the accumulated powers.
7. The receiver of claim 6 , wherein the processor is further programmed to repeat determining and subtracting for a plurality of frequencies thereby generating a two-dimensional delay-Doppler accumulated power pattern with suppressed interference effect.
8. The receiver of claim 6 , wherein the average value is an arithmetic mean, a median, or a mode.
9. The receiver of claim 6 , wherein the average value is obtained by referencing a lookup table.
10. The receiver of claim 6 , wherein a frequency is a Doppler bin of the two-dimensional delay-Doppler accumulated power pattern and a time point is a code bin of the two-dimensional delay-Doppler accumulated power pattern.
11. The receiver of claim 6 , wherein the processor is a 32 bit processor.