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 are described that illustrate how to determine whether an image includes a travel way, and if so how to determine an angle between a longitudinal axis of a vehicle and a longitudinal axis of a travel way line, and a shortest distance between a reference point on a vehicle and a longitudinal axis of the travel way line.

Abstract: Methods and systems to process and assure integrity of DME and/or VOR measurements, detect the effects of GNSS jamming and/or spoofing events, identify GNSS measurements affected by the GNSS jamming and/or spoofing events, and assure the integrity of the GNSS measurements unaffected by jamming and/or spoofing events in a vehicle navigation system are disclosed. The methods are implemented to integrate inertial measurements, GNSS measurements, and DME/VOR measurements for the vehicle, and apply solution separation techniques to all of the measurements. The solution separation techniques use a main filter for hybridization of the inertial measurements, the GNSS measurements, and the DME/VOR measurements, with additional sub-solution filters and sub-sub-solution filters that use combinations of these measurements. This provides common processing of the GNSS and DME/VOR sensors in a single hybridization and solution separation framework.

Abstract: Systems and methods for implementing single differences within a solution separation framework are provided. In certain embodiments, a method includes processing pseudorange measurements to determine a full navigation solution by applying a single difference between the pseudorange measurements. The method additionally includes performing innovation sequence monitoring. Also, the method includes processing a subset of the pseudorange measurements to determine a set of navigation sub-solutions by applying a single difference between the pseudorange measurements, wherein a result of the innovation sequence monitoring is applied to the set of navigation sub-solutions; and providing faults detection and computing protection levels of quantities of navigation information based on a full navigation solution estimate, navigation sub-solution estimates, dependence among the full navigation solution and the set of navigation sub-solutions, and probabilities of missed detection and false alert.

Abstract: A method for determining fleet wide integrity comprises forming a user measurement block for each user in a fleet network, the user measurement block comprising: navigation measurements received by the user, relative user measurements received by the user from other users, and navigation state and integrity solutions. The user measurement block is signed and sent to all other users for validation. Each user executes a numerical process to determine a navigation state and integrity of all users. A fleet state block is formed comprising: a header including a hash of last valid fleet state block header, a nonce-proof of work, and a root hash of Merkle tree; and a data block including measurement, state, and integrity information of the fleet. The fleet state block is sent to all other users for validation. If the fleet state block passes validation, the user forms a chain of fleet state blocks.

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: System and methods are described that illustrate how to more accurately determine at least one state variable of a vehicle using imaging of a travel way line. Imaging can be used to determine an angle between a longitudinal axis of the travel way line and a longitudinal axis of the vehicle, a shortest distance between the center axis and a reference point on or in the vehicle, and corresponding errors. The determined angle, the determined distance, and the corresponding errors can be used to more accurately determine the at least one state variable.

Abstract: Systems and methods are described that illustrate how to determine whether an image includes a travel way, and if so how to determine an angle between a longitudinal axis of a vehicle and a longitudinal axis of a travel way line, and a shortest distance between a reference point on a vehicle and a longitudinal axis of the travel way line.

Abstract: Systems and methods for implementing single differences within a solution separation framework are provided. In certain embodiments, a method includes processing pseudorange measurements to determine a full navigation solution by applying a single difference between the pseudorange measurements. The method additionally includes performing innovation sequence monitoring. Also, the method includes processing a subset of the pseudorange measurements to determine a set of navigation sub-solutions by applying a single difference between the pseudorange measurements, wherein a result of the innovation sequence monitoring is applied to the set of navigation sub-solutions; and providing faults detection and computing protection levels of quantities of navigation information based on a full navigation solution estimate, navigation sub-solution estimates, dependence among the full navigation solution and the set of navigation sub-solutions, and probabilities of missed detection and false alert.

Abstract: An integrity monitoring method for navigation systems with heterogeneous measurements is provided. Measurements from a plurality of different type navigation aiding sources are categorized by an information domain, an aiding class and an aiding section. The information domain is a category of at least one of estimated states and measurements that represent a same physical category. The aiding class is a category that uses a same physical method to acquire measurements. The aiding section is a category of measurements from the same aiding source. The measurements are organized into a plurality of measurement clusters based at least in part on measurement fault modes to be detected, measurement fault modes to be excluded, available computer resources and required performance. An integrity monitoring algorithm is applied to the measurement clusters to determine an integrity solution for all defined integrity monitoring classes.

Abstract: An integrity monitoring method for navigation systems with heterogeneous measurements is provided. Measurements from a plurality of different type navigation aiding sources are categorized by an information domain, an aiding class and an aiding section. The information domain is a category of at least one of estimated states and measurements that represent a same physical category. The aiding class is a category that uses a same physical method to acquire measurements. The aiding section is a category of measurements from the same aiding source. The measurements are organized into a plurality of measurement clusters based at least in part on measurement fault modes to be detected, measurement fault modes to be excluded, available computer resources and required performance. An integrity monitoring algorithm is applied to the measurement clusters to determine an integrity solution for all defined integrity monitoring classes.

Abstract: An attitude and heading reference system (AHRS) for a vehicle comprises an IMU that generates inertial measurements, a heading source that generates heading measurements, an attitude filter in communication with the IMU, and a heading filter in communication with the heading source. The attitude filter receives inertial measurements from the IMU; computes an attitude estimation comprising attitude estimates and covariances for the attitude estimates; and outputs the attitude estimation. The heading filter receives the heading measurements, when available, from the heading source; receives the attitude estimation, comprising the attitude estimates and the covariances for the attitude estimates; computes a heading estimation comprising a heading mean estimate and a heading variance; and outputs the heading estimation.