A demodulator comprises a first-stage carrier demodulator and a second-stage carrier demodulator. The first-stage carrier demodulator is configured to remove or compensate for the tracking error in the baseband signal, where the tracking error comprises aggregate, channel tracking error of carrier phase for the same received band, sub-band, (baseband) GNSS satellite channel, or set GNSS channels. The second stage carrier demodulator is configured to remove or strip a carrier signal component without any unwanted image or carrier-related frequency artifacts and to prepare for correlation-based decoding or demodulation of the encoded baseband signal by the correlators. First correlators are configured to determine correlations for code phase tracking loop, where the code phase tracking loop is configured to estimate a corresponding code error component of the tracking error for the code local oscillator for a respective channel. Secondary correlators are configured to determine correlations for a carrier phase tracking loop, where the carrier phase tracking loop configured to estimate a corresponding aggregate feedback error for multiple channels or a set of channels.

A demodulator comprises a first-stage carrier demodulator and a second-stage carrier demodulator. The first-stage carrier demodulator is configured to remove or compensate for the tracking error in the baseband signal, where the tracking error comprises aggregate, channel tracking error of carrier phase for the same received band, sub-band, (baseband) GNSS satellite channel, or set GNSS channels. The second stage carrier demodulator is configured to remove or strip a carrier signal component without any unwanted image or carrier-related frequency artifacts and to prepare for correlation-based decoding or demodulation of the encoded baseband signal by the correlators. First correlators are configured to determine correlations for code phase tracking loop, where the code phase tracking loop is configured to estimate a corresponding code error component of the tracking error for the code local oscillator for a respective channel. Secondary correlators are configured to determine correlations for a carrier phase tracking loop, where the carrier phase tracking loop configured to estimate a corresponding aggregate feedback error for multiple channels or a set of channels.

A GNSS receiver comprises a memory interface and a vector processor. The vector processor is configured to: receive, via the memory interface, an array comprising a plurality of correlation results stored in a memory, each correlation result associated with a respective combination of possible receiver parameters for the GNSS receiver; process the array to identify a subset of the correlation results in the array; and retain, in the memory, the identified subset and discard, from the memory, those correlation results of the plurality of correlation results not in the identified subset.

A GNSS receiver comprises a memory interface and a vector processor. The vector processor is configured to: receive, via the memory interface, an array comprising a plurality of correlation results stored in a memory, each correlation result associated with a respective combination of possible receiver parameters for the GNSS receiver; process the array to identify a subset of the correlation results in the array; and retain, in the memory, the identified subset and discard, from the memory, those correlation results of the plurality of correlation results not in the identified subset.

A global navigation satellite system (GNSS) receiver for improving accuracy of a GNSS position estimation using a sigma-delta based fractional interpolation in a delay-locked loop is provided. The GNSS receiver includes a correlator, a code phase discriminator, a first loop filter, a code numerically controlled oscillator, and a sigma-delta modulator. The correlator correlates a GNSS C/A signal received from a satellite with a locally generated GNSS C/A code by multiplying the locally generated GNSS C/A code with incoming data samples. The code phase discriminator determines a delay between the locally generated GNSS C/A code and the GNSS C/A signal received from the satellite. The first loop filter averages the delay measured by the code phase discriminator. The code numerically controlled oscillator generates the local GNSS C/A code based on a unique CA code that corresponds to the satellite. The sigma-delta modulator imparts a fractional delay to the locally generated GNSS C/A code based on an output of the first loop filter.

A global navigation satellite system (GNSS) receiver for improving accuracy of a GNSS position estimation using a sigma-delta based fractional interpolation in a delay-locked loop is provided. The GNSS receiver includes a correlator, a code phase discriminator, a first loop filter, a code numerically controlled oscillator, and a sigma-delta modulator. The correlator correlates a GNSS C/A signal received from a satellite with a locally generated GNSS C/A code by multiplying the locally generated GNSS C/A code with incoming data samples. The code phase discriminator determines a delay between the locally generated GNSS C/A code and the GNSS C/A signal received from the satellite. The first loop filter averages the delay measured by the code phase discriminator. The code numerically controlled oscillator generates the local GNSS C/A code based on a unique CA code that corresponds to the satellite. The sigma-delta modulator imparts a fractional delay to the locally generated GNSS C/A code based on an output of the first loop filter.

A method and a function for checking the integrity of the processing of a radionavigation signal emitted by a satellite, the signal being received by a receiver comprising reception means and processing means, the processing means comprising a linear anti-interference filter, the integrity checking method comprising at least a first phase of detection of a risk of false lock-on comprising the following steps: a step of recovery of a nominal theoretical self-correlation function of the received signal not processed by the linear anti-interference filter; a step of determination of a mean theoretical self-correlation function of the signal received and processed by the linear anti-interference filter over a defined integration period; a step of determination of the number of local maxima of the modulus or of the modulus squared of the mean theoretical self-correlation function, a risk of false lock-on being detected if the number of local maxima is greater than or equal to two.

A method and a function for checking the integrity of the processing of a radionavigation signal emitted by a satellite, the signal being received by a receiver comprising reception means and processing means, the processing means comprising a linear anti-interference filter, the integrity checking method comprising at least a first phase of detection of a risk of false lock-on comprising the following steps: a step of recovery of a nominal theoretical self-correlation function of the received signal not processed by the linear anti-interference filter; a step of determination of a mean theoretical self-correlation function of the signal received and processed by the linear anti-interference filter over a defined integration period; a step of determination of the number of local maxima of the modulus or of the modulus squared of the mean theoretical self-correlation function, a risk of false lock-on being detected if the number of local maxima is greater than or equal to two.

Disclosed are methods and apparatuses for transmitting and receiving characteristic information of a GNSS subframe. A method for transmitting and receiving characteristic information of a GNSS subframe, as a method for a first device, may comprise: receiving a subframe including first information, which is characteristic information of the subframe, from a second device; checking a format of the subframe on the basis of the first information; and determining whether to decode data included in the subframe on the basis of the checked format of the subframe.

Disclosed are methods and apparatuses for transmitting and receiving characteristic information of a GNSS subframe. A method for transmitting and receiving characteristic information of a GNSS subframe, as a method for a first device, may comprise: receiving a subframe including first information, which is characteristic information of the subframe, from a second device; checking a format of the subframe on the basis of the first information; and determining whether to decode data included in the subframe on the basis of the checked format of the subframe.