Abstract: Systems and methods for estimating attitude and heading are provided. The systems and methods utilize carrier phase single difference (CSD) measurements or carrier phase double difference (CDD) measurements and a validation test for CSD or CDD measurement residuals. The systems and methods include applying a wrapping function with limit of ±half of the GNSS carrier signal wavelength to CSD or CDD measurement residuals to generate refined CSD or CDD measurement residuals and validating the refined CSD or CDD measurement residuals variance to determine valid CSD or CDD measurements. By using the validated CSD and CDD measurements, the systems and methods enable low grade hybrid inertial navigation systems to estimate attitude and heading with integrity and without a magnetometer or the need for integer ambiguity resolution even during the static or steady phases of flight/operation.

Abstract: Systems and methods for calculating single delta range differences using synthetic clock steering are provided. In certain embodiments, a system includes a first GNSS receiver that provides first delta range measurements and first measurement times associated with a plurality of GNSS satellites. The system further includes a second GNSS receiver that provides second delta range measurements and second measurement times associated with the plurality of GNSS satellites. Additionally, the system includes a processing unit that executes instructions that cause the processing unit to synchronize the second delta range measurements with the first delta range measurements to create synchronized delta range measurements. The executable instructions also cause the processing unit to calculate a single difference of the first delta range measurements and the synchronized delta range measurements for at least one satellite in the plurality of GNSS satellites.

Abstract: Systems and methods for estimating attitude and heading are provided. The systems and methods utilize carrier phase single difference (CSD) measurements or carrier phase double difference (CDD) measurements and a validation test for CSD or CDD measurement residuals. The systems and methods include applying a wrapping function with limit of ±half of the GNSS carrier signal wavelength to CSD or CDD measurement residuals to generate refined CSD or CDD measurement residuals and validating the refined CSD or CDD measurement residuals variance to determine valid CSD or CDD measurements. By using the validated CSD and CDD measurements, the systems and methods enable low grade hybrid inertial navigation systems to estimate attitude and heading with integrity and without a magnetometer or the need for integer ambiguity resolution even during the static or steady phases of flight/operation.

Abstract: Systems and methods for calculating single delta range differences using synthetic clock steering are provided. In certain embodiments, a system includes a first GNSS receiver that provides first delta range measurements and first measurement times associated with a plurality of GNSS satellites. The system further includes a second GNSS receiver that provides second delta range measurements and second measurement times associated with the plurality of GNSS satellites. Additionally, the system includes a processing unit that executes instructions that cause the processing unit to synchronize the second delta range measurements with the first delta range measurements to create synchronized delta range measurements. The executable instructions also cause the processing unit to calculate a single difference of the first delta range measurements and the synchronized delta range measurements for at least one satellite in the plurality of GNSS satellites.

Abstract: Systems and methods for reducing bias impact on GNSS integrity are described herein. In certain embodiments, a method includes determining a phase of travel of a vehicle. The method also includes determining a probability of hazardously misleading information (PHMI) for the corresponding phase of travel. Further, the method includes determining a protection level (PL) using based on the PHMI, wherein the PL is calculated based on a standard deviation of position error plus a standard deviation of bias along an axis of interest. Additionally, the method includes comparing the protection level against an alert limit.

Abstract: Systems and methods for reducing bias impact on GNSS integrity are described herein. In certain embodiments, a method includes determining a phase of travel of a vehicle. The method also includes determining a probability of hazardously misleading information (PHMI) for the corresponding phase of travel. Further, the method includes determining a protection level (PL) using based on the PHMI, wherein the PL is calculated based on a standard deviation of position error plus a standard deviation of bias along an axis of interest. Additionally, the method includes comparing the protection level against an alert limit.

Abstract: A baseband tracking channel in a GNSS receiver is provided. The baseband tracking channel comprises: a code generator to generate a local signal correlating with an incoming signal received by the GNSS receiver; a multiplier that multiplies the local signal with a baseband signal corresponding to an incoming signal received by the GNSS receiver to generate a code removed signal; a prompt correlator including at least one integration register that integrates samples of the code removed signal corresponding to a first portion of each pseudorandom noise code chip of the code removed signal to provide a first integration register output, and integrates samples corresponding to a second portion of each PRN code chip to provide a second integration register output; and a side peak tracking detection module that generates information indicating when side peak tracking is occurring based on the first integration register output and the second integration register output.

Abstract: A GNSS receiver comprising at least one processing device configured to, in at least one first process: group satellites into subsets for a first distribution, each satellite included in one subset, each subset includes at least one satellite and less than all satellites, at least one subset includes more than one satellite; store the first distribution in memory as primary distribution; calculate a protection level based on navigation sub-solutions calculated using the first distribution; determine whether a new distribution of satellites is needed; when new distribution is not needed, the processing device configured to recalculate the protection level based on second navigation sub-solutions calculated using the first distribution; when new distribution is needed, the processing device configured to: group satellites into subsets for a second distribution; store the second distribution in memory as the primary distribution; recalculate the protection level based on third navigation sub-solutions calculated

Abstract: A global navigation satellite system (GNSS) receiver including a processing device configured to: group GNSS satellites in view of the GNSS receiver into subsets based on relative geometries of the GNSS satellites relative to the GNSS receiver, wherein a GNSS satellite of the GNSS satellites is included in at most one subset of the subsets, wherein each subset of the subsets includes at least one GNSS satellite of the GNSS satellites and less than all GNSS satellites of the GNSS satellites, and wherein at least one subset includes more than one GNSS satellite; calculate a plurality of navigation sub-solutions based on data received at the GNSS receiver from the GNSS satellites using at least one GNSS antenna, wherein each navigation sub-solution of the navigation sub-solutions is calculated with at least one different subset of the subsets excluded; and calculate a protection level based on the navigation sub-solutions.

Abstract: A Global Navigation Satellite System receiver comprising at least one processor is provided.

Abstract: An efficient covariance matrix computation method is disclosed in connection with certain GNSS applications, including Advanced Receiver Autonomous Integrity Monitoring (ARAIM) and geometry screening. The system and method of the present application enable computation of multiple covariance matrices with substantially greater efficiency than previous approaches, including the rank-one update formula. For example, the system and method of the present application advantageously involves substantially fewer and simpler arithmetic operations than previous approaches. In addition, unlike the rank-one update formula, the system and method of the present application can be used to compute the subsolution in which all the satellites of a given constellation are removed.

Abstract: A baseband tracking channel in a GNSS receiver is provided. The baseband tracking channel comprises: a code generator to generate a local signal correlating with an incoming signal received by the GNSS receiver; a multiplier that multiplies the local signal with a baseband signal corresponding to an incoming signal received by the GNSS receiver to generate a code removed signal; a prompt correlator including at least one integration register that integrates samples of the code removed signal corresponding to a first portion of each pseudorandom noise code chip of the code removed signal to provide a first integration register output, and integrates samples corresponding to a second portion of each PRN code chip to provide a second integration register output; and a side peak tracking detection module that generates information indicating when side peak tracking is occurring based on the first integration register output and the second integration register output.

Abstract: A global navigation satellite system (GNSS) receiver includes: at least one radio frequency (RF) front end configured to receive a GNSS signal from a single GNSS antenna and to digitize the GNSS signal into a digitized GNSS signal; at least one processor configured to: calculate weight to be applied to a sample of a block of samples of the digitized GNSS signal; apply the weight to at least one sample of the block of samples of the digitized GNSS signal to create a weighted GNSS signal; and perform signal processing on the weighted GNSS signal.

Abstract: A Global Navigation Satellite System receiver comprising at least one processor is provided.

Abstract: A GNSS receiver comprising at least one processing device configured to, in at least one first process: group satellites into subsets for a first distribution, each satellite included in one subset, each subset includes at least one satellite and less than all satellites, at least one subset includes more than one satellite; store the first distribution in memory as primary distribution; calculate a protection level based on navigation sub-solutions calculated using the first distribution; determine whether a new distribution of satellites is needed; when new distribution is not needed, the processing device configured to recalculate the protection level based on second navigation sub-solutions calculated using the first distribution; when new distribution is needed, the processing device configured to: group satellites into subsets for a second distribution; store the second distribution in memory as the primary distribution; recalculate the protection level based on third navigation sub-solutions calculated

Abstract: Embodiments for satellite subset selection for use in monitoring the integrity of computed navigation solutions are disclosed. In one embodiment, a Global Navigation Satellite System (GNSS) receiver comprises: a processing device configured to: group a plurality of satellites in view of the GNSS receiver into a plurality of subsets, wherein a satellite of the plurality of satellites is included in at most one subset of the plurality of subsets, wherein each subset of the plurality of subsets includes at least one satellite of the plurality of satellites and less than all satellites of the plurality of satellites, and wherein at least one subset includes more than one satellite; calculate a plurality of navigation sub-solutions, wherein each navigation sub-solution of the plurality of navigation sub-solutions is calculated with at least one different subset of the plurality of subsets excluded; and calculate a protection level.

Abstract: Systems and methods of determining ionosphere delay for a GNSS system are provided. In one embodiment, a GNSS system includes an antenna configured to receive GNSS signals from one or more GNSS satellites. The system further includes a signal processing circuit coupled to the antenna and configured to down convert the GNSS signals from RF to IF. The system further includes a processing device coupled to a memory, the memory including a database of a plurality of weights and an activation function for a neural network, the neural network trained to output an approximation of an output of a NeQuick model. The processing device configured to: apply the plurality of weights and the activation function for the neural network to a plurality of inputs generated from the GNSS signals; and estimate an indication of ionosphere delay based on an output of the neural network.

Abstract: A global navigation satellite system (GNSS) receiver includes: at least one radio frequency (RF) front end configured to receive a GNSS signal from a single GNSS antenna and to digitize the GNSS signal into a digitized GNSS signal; at least one processor configured to: calculate weight to be applied to a sample of a block of samples of the digitized GNSS signal; apply the weight to at least one sample of the block of samples of the digitized GNSS signal to create a weighted GNSS signal; and perform signal processing on the weighted GNSS signal.

Abstract: A global navigation satellite system (GNSS) receiver includes a processor to determine whether a first satellite is in view of GNSS receiver; whether a second satellite is in view of GNSS receiver when first satellite is in view of GNSS receiver; and whether a third satellite is in view of GNSS receiver when first satellite is not in view of GNSS receiver. Second satellite was previously determined more likely to be in view when first satellite is in view based on a first average distance between first satellite and second satellite based on a first orbit of first satellite and a second orbit of second satellite. Third satellite was previously determined more likely to be in view when first satellite is not in view based on a second average distance between first satellite and third satellite based on first orbit of first satellite and a third orbit of third satellite.

Abstract: A method of performing a discrete Fourier transform (DFT) on one or more data samples in a global navigation satellite system baseband tracking channel is provided. The method comprises loading a pseudorandom noise code generator with a constant value in the baseband tracking channel; setting a tracking loop integration time according to a selected frequency resolution; updating a carrier generator with a selected DFT frequency in the baseband tracking channel; integrating a data sample in the baseband tracking channel; and storing the integrated data sample in a DFT bin. The method determines whether all DFT bins have been received, and if all DFT bins have not been received, the method repeats starting with updating the carrier generator, until all DFT bins have been received.