System and receiver for GNSS signals

A method, comprising:

• using a phase-locked loop (PLL), generating a first local oscillator (LO) signal and a voltage-controlled oscillator (VCO) signal having a signal frequency higher than a frequency of the first local oscillator signal;
• using a first quadrature demodulator configured to downconvert global navigation satellite system (GNSS) signals received from a plurality of GNSS satellites over a set of carrier frequencies to produce a first intermediate frequency (IF) signal;
• processing a first frequency band corresponding to a first plurality of GNSS satellites comprising passing the first IF signal to a baseband processor;
• processing second frequency band comprising dividing the first LO signal by a first division ratio to form a second LO signal, mixing the first IF signal with the second LO signal to form a second IF signal, and passing the second IF signal to the baseband processor;
• and
• processing third frequency band comprising dividing the VCO signal by a second division ratio to form a third LO signal, mixing the first IF signal with the third LO signal to form a third IF signal, and passing the third IF signal to the baseband processor, wherein the third frequency band is higher than the second frequency band, and the first frequency band is higher than the third frequency band.

A system, comprising:

• an input node configured to receive a set of global navigation satellite system (GNSS) signals transmitted from a plurality of GNSS satellites over a set of carrier frequencies;
• a phase-locked loop, PLL configured to provide a first local oscillator signal and a voltage-controlled oscillator, VCO signal;
• a first quadrature demodulator coupled to the input node and to the PLL, the first quadrature demodulator configured to apply quadrature demodulation processing to the set of GNSS signals based on the first local oscillator signal received from the PLL, the first quadrature demodulator providing a first set of in-phase signals and a first set of quadrature signals as a result, wherein in-phase signals of the first set of in-phase signals and quadrature signals of the first set of quadrature signals have a first intermediate frequency lower than carrier frequencies of the set of carrier frequencies of GNSS signals of the set of GNSS signals;
• a first signal processing chain coupled to the first quadrature demodulator to receive the set of in-phase signals and the first set of quadrature signals, the first signal processing chain comprising a first variable gain amplifier, VGA coupled to the first quadrature demodulator, the VGA configured to apply a first variable gain amplification to the first set of in-phase signals and to the first set of quadrature signals, providing a first in-phase signal component and a first quadrature signal component as a result;
• a second signal processing chain coupled to the first quadrature demodulator to receive the first set of in-phase signals and the first set of quadrature signals and coupled to the PLL to receive the first local oscillator signal, the second signal processing chain comprising:
• a first polyphase filter configured to apply polyphase filtering to the first set of in-phase signals and to the first set of quadrature signals, producing a first set of filtered in-phase signals and a first set of filtered quadrature signals as a result,
• a first adder coupled to the first polyphase filter to receive the first set of filtered in-phase signals and the first set of filtered quadrature signals, the first adder configured to provide a first sum signal as a sum of the first set of filtered in-phase signals and the first set of filtered quadrature signals,
• a first frequency divider configured to apply frequency division to the first local oscillator signal, producing a second local oscillator signal as a result, wherein the second local oscillator signal has a second local oscillator frequency that is a fraction of the frequency of the first local oscillator signal,
• a second quadrature demodulator coupled to the adder and to the first frequency divider, the second quadrature demodulator configured to apply second quadrature demodulation processing to the first sum signal, providing, based on the second local oscillator signal, a second set of in-phase signals and a second set of quadrature signals, the second set of in-phase signals and the second set of quadrature signals having a second intermediate frequency lower than the first intermediate frequency, and
• a second VGA configured to apply a second variable gain amplification to the second set of in-phase signals and to the second set of quadrature signals, the second VGA configured to produce a second in-phase signal component and a second quadrature signal component as a result;
• and
• a third signal processing chain coupled to the first quadrature demodulator to receive the set of in-phase signals and the first set of quadrature signals and coupled to the PLL to receive the VCO signal, the third signal processing chain comprising:
• a second polyphase filter configured to apply second polyphase filtering to the first set of in-phase signals and to the first set of quadrature signals, producing a second set of filtered in-phase signals and a second set of filtered quadrature signals as a result,
• a second adder coupled to the second polyphase filter to receive the second set of filtered in-phase signals and the second set of filtered quadrature signals therefrom, the second adder configured to provide a second sum signal as a sum of the second set of filtered in-phase signals and the second set of filtered quadrature signals,
• a second frequency divider configured to apply a second frequency division to the VCO signal, producing a third local oscillator signal as a result, wherein the third local oscillator signal has a third local oscillator frequency that is a fraction of the frequency of the VCO signal, and
• a third quadrature demodulator coupled to the second adder and to the second frequency divider, the third quadrature demodulator configured to apply third quadrature demodulation processing to the second sum signal, providing, based on the third local oscillator signal, a third set of in-phase signals and a third set of quadrature signals, the second set of in-phase signals and the second set of quadrature signals having a third intermediate frequency lower than the second intermediate frequency, and
• a third VGA configured to apply a third variable gain amplification to the third set of in-phase signals and to the third set of quadrature signals, the third VGA configured to produce a third in-phase signal component and a third quadrature signal component as a result.