Abstract: A method for multi-track environmental fault monitoring for aerial platforms includes estimating a normalized squared residual error (NSRE) for each of one or more satellite-receiver tracks over time. The method also includes determining an averaged NSRE for each satellite-receiver track by averaging the NSRE over multiple time windows. The method further includes performing a threshold test on the averaged NSRE to determine a filter state. In addition, the method includes determining whether to apply a scale factor for each satellite-receiver track based on the filter state.

Abstract: A method includes repeatedly determining a distance of an aircraft from a landing location. The method also includes, during a first stage in which the aircraft is at least a threshold distance from the landing location, performing iono-free processing during navigation of the aircraft. The method further includes, during a second stage in which the aircraft is less than the threshold distance from the landing location and a velocity of the aircraft is greater than a velocity threshold, performing divergence-free processing during navigation of the aircraft to address possible ionospheric threats. In addition, the method includes, during a third stage in which the aircraft is less than the threshold distance from the landing location and the velocity of the aircraft is less than the velocity threshold, calculating one or more floor values for a Differential Ionospheric Correction (DIC) sigma, and determining a navigation solution to protect against nominal ionospheric conditions.

Abstract: FAST provides a method of “bootstrapping” a pseudo-range (PR) stage and one or more carrier-phase (CP) stages to quickly produce a highly accurate, high integrity receiver-to-receiver lever arm survey based on differential GNSS processing. The lever arm estimates of a previous stage are used to resolve the carrier phase ambiguities of the next stage. The method can be integrated with the warm-up of the integrity monitors to reduce the entire survey and warm-up startup time to 90 minutes or less, which is critical for mobile and make shift and precision approach and (automated) landing operations.

Abstract: Differential ranging measurements are formed using first ranging measurements from reference GNSS receivers and second ranging measurements from GNSS receivers on a rover, the first and second ranging measurements received from a plurality of GNSS satellites. A main navigation solution and a main protection level (PL) set are computed based on the differential ranging measurements. Ionospheric threat scenarios associated with experiencing severe ionospheric gradients to one or more of the plurality of GNSS satellites are determined. A supplemental navigation solution and a corresponding supplemental PL set for each of the plurality of ionospheric threat scenarios are computed. A maximum PL set is selected based on the main PL set and the supplemental PL sets to form a final PL set that protects the main solution against nominal navigation threats and severe ionospheric threats.

Abstract: FAST provides a method of “bootstrapping” a pseudo-range (PR) stage and one or more carrier-phase (CP) stages to quickly produce a highly accurate, high integrity receiver-to-receiver lever arm survey based on differential GNSS processing. The lever arm estimates of a previous stage are used to resolve the carrier phase ambiguities of the next stage. The method can be integrated with the warm-up of the integrity monitors to reduce the entire survey and warm-up startup time to 90 minutes or less, which is critical for mobile and make shift and precision approach and (automated) landing operations.

Abstract: Differential ranging measurements are formed using first ranging measurements from reference GNSS receivers and second ranging measurements from GNSS receivers on a rover, the first and second ranging measurements received from a plurality of GNSS satellites. A main navigation solution and a main protection level (PL) set are computed based on the differential ranging measurements. Ionospheric threat scenarios associated with experiencing severe ionospheric gradients to one or more of the plurality of GNSS satellites are determined. A supplemental navigation solution and a corresponding supplemental PL set for each of the plurality of ionospheric threat scenarios are computed. A maximum PL set is selected based on the main PL set and the supplemental PL sets to form a final PL set that protects the main solution against nominal navigation threats and severe ionospheric threats.

Abstract: Technology for correcting a misalignment between an inertial measurement unit (IMU) and a moving platform is described. A first attitude of the moving platform can be identified based on a truth source. A second attitude of the moving platform can be calculated using IMU measurements. A delta attitude can be calculated from a difference between the first attitude and the second attitude. Natural error can be removed from the delta attitude to produce an angular misalignment value between axes of the IMU and axes of the moving platform. A total misalignment value can be determined by adding the angular misalignment value to a baseline misalignment value. The IMU can incorporate the total misalignment value for subsequent attitude measurements of the moving platform in order to produce substantially accurate attitude measurements of the moving platform when the axes of the IMU are misaligned with the axes of the moving platform.

Abstract: The concepts, systems and methods described herein are directed towards real time carrier phase monitoring and platform attitude solutions on a moving platform. In an embodiment, highly accurate platform attitude and monitored carrier phases can be determined in a single step and use data screening, error bounds inflation and statistical tests to ensure both inputs and outputs of an attitude solution are self-consistent. The method includes determining a carrier phase error level for each of the satellite-receiver tracks, identifying the satellite-receiver tracks having the carrier phase error level greater than or equal to a carrier phase error threshold, generating an attitude correction using the received data from the one or more satellite-receiver tracks having the carrier phase error level less than the carrier phase error threshold and determining a convergence state of the attitude correction. The carrier phase monitoring may be activated or dis-activated based on the convergence level.

Abstract: Technology for surveying sensor locations on a physical platform is described. An estimated baseline vector can be calculated between a temporary navigation sensor and each fixed navigation sensor in a group of fixed navigation sensors. The temporary navigation sensor can be temporarily placed on the physical platform. The fixed navigation sensors can be installed on the physical platform. A refined baseline vector between the temporary navigation sensor and each fixed navigation sensor can be successively calculated by fixing carrier phase integer ambiguities that are variables used in the estimation of the baseline vector. A final survey distance between the temporary navigation sensor and each of the fixed navigation sensors can be generated using the refined baseline vector.

Abstract: The concepts, systems and methods described herein are directed towards real time carrier phase monitoring and platform attitude solutions on a moving platform. In an embodiment, highly accurate platform attitude and monitored carrier phases can be determined in a single step and use data screening, error bounds inflation and statistical tests to ensure both inputs and outputs of an attitude solution are self-consistent. The method includes determining a carrier phase error level for each of the satellite-receiver tracks, identifying the satellite-receiver tracks having the carrier phase error level greater than or equal to a carrier phase error threshold, generating an attitude correction using the received data from the one or more satellite-receiver tracks having the carrier phase error level less than the carrier phase error threshold and determining a convergence state of the attitude correction. The carrier phase monitoring may be activated or dis-activated based on the convergence level.

Abstract: A differential global positioning system (DGPS) processor can include an almost fixed integer ambiguity (AFIA) module for generating in real-time a multiple dimensional state vector of integer ambiguities and multiple dimensional corrections. The AFIA module can use double difference (DD) measurements for pseudo-range (PR) and carrier phase (CP) pairs generated from at least three global positioning system (GPS) receivers. A DGPS processor can be included in a high data rate real time attitude determination (RTAD) system to achieve high heading accuracy with high integrity.

Abstract: Technology for correcting a misalignment between an inertial measurement unit (IMU) and a moving platform is described. A first attitude of the moving platform can be identified based on a truth source. A second attitude of the moving platform can be calculated using IMU measurements. A delta attitude can be calculated from a difference between the first attitude and the second attitude. Natural error can be removed from the delta attitude to produce an angular misalignment value between axes of the IMU and axes of the moving platform. A total misalignment value can be determined by adding the angular misalignment value to a baseline misalignment value. The IMU can incorporate the total misalignment value for subsequent attitude measurements of the moving platform in order to produce substantially accurate attitude measurements of the moving platform when the axes of the IMU are misaligned with the axes of the moving platform.

Abstract: Technology for surveying sensor locations on a physical platform is described. An estimated baseline vector can be calculated between a temporary navigation sensor and each fixed navigation sensor in a group of fixed navigation sensors. The temporary navigation sensor can be temporarily placed on the physical platform. The fixed navigation sensors can be installed on the physical platform. A refined baseline vector between the temporary navigation sensor and each fixed navigation sensor can be successively calculated by fixing carrier phase integer ambiguities that are variables used in the estimation of the baseline vector. A final survey distance between the temporary navigation sensor and each of the fixed navigation sensors can be generated using the refined baseline vector.

Abstract: Systems and techniques for transferring electronic data include enabling instant messaging communication between a sender an at least one recipient through an instant messaging host. In addition, voice communication is enabled between the sender and the recipient through the instant messaging host.

Abstract: Technology for generating a H1 protection level from an N?1 position in a global positioning system (GPS) receiver is disclosed. One approach can include an H1 monitor configured to generate an H1 protection level from an N number of N?1 positions. The N?1 position can be derived by a differential global positioning system (GPS) satellite measurement removed from a plurality of N differential GPS satellites measurements.

Abstract: A method and system for reduction of quantization-induced block-discontinuities arising from lossy compression and decompression of continuous signals, especially audio signals. One embodiment encompasses a general purpose, ultra-low latency, efficient audio codec algorithm. More particularly, the invention includes a method and apparatus for compression and decompression of audio signals using a novel boundary analysis and synthesis framework to substantially reduce quantization-induced frame or block discontinuity; a novel adaptive cosine packet transform (ACPT) as the transform of choice to effectively capture the input audio characteristics; a signal-residue classifier to separate the strong signal clusters from the noise and weak signal components (collectively called residue); an adaptive sparse vector quantization (ASVQ) algorithm for signal components; a stochastic noise model for the residue; and an associated rate control algorithm.

Abstract: Technology for generating a H1 protection level from an N?1 position in a global positioning system (GPS) receiver is disclosed. One approach can include an H1 monitor configured to generate an H1 protection level from an N number of N?1 positions. The N?1 position can be derived by a differential global positioning system (GPS) satellite measurement removed from a plurality of N differential GPS satellites measurements.

Abstract: A method and system for reduction of quantization-induced block-discontinuities arising from lossy compression and decompression of continuous signals, especially audio signals. One embodiment encompasses a general purpose, ultra-low latency, efficient audio codec algorithm. More particularly, the invention includes a method and apparatus for compression and decompression of audio signals using a novel boundary analysis and synthesis framework to substantially reduce quantization-induced frame or block discontinuity; a novel adaptive cosine packet transform (ACPT) as the transform of choice to effectively capture the input audio characteristics; a signal-residue classifier to separate the strong signal clusters from the noise and weak signal components (collectively called residue); an adaptive sparse vector quantization (ASVQ) algorithm for signal components; a stochastic noise model for the residue; and an associated rate control algorithm.

Abstract: A method and system for reduction of quantization-induced block-discontinuities arising from lossy compression and decompression of continuous signals, especially audio signals. One embodiment encompasses a general purpose, ultra-low latency, efficient audio codec algorithm. More particularly, the invention includes a method and apparatus for compression and decompression of audio signals using a novel boundary analysis and synthesis framework to substantially reduce quantization-induced frame or block discontinuity; a novel adaptive cosine packet transform (ACPT) as the transform of choice to effectively capture the input audio characteristics; a signal-residue classifier to separate the strong signal clusters from the noise and weak signal components (collectively called residue); an adaptive sparse vector quantization (ASVQ) algorithm for signal components; a stochastic noise model for the residue; and an associated rate control algorithm.

Abstract: Systems and techniques for transferring electronic data include enabling instant messaging communication between a sender an at least one recipient through an instant messaging host. In addition, voice communication is enabled between the sender and the recipient through the instant messaging host.