Abstract: This application provides a method for calibrating satellite short message communication charging. In the method, an electronic device sends a target satellite short message to a satellite, performs a pre-fee-deduction operation for a satellite short message service, and updates a first parameter to a first value, where the first parameter is a remaining quota that is of the satellite short message service and that is stored in the electronic device. When the electronic device is connected to a communication network, the electronic device sends the first value to a server. The electronic device receives a first calibration result sent by the server, where the first calibration result indicates whether the first value is consistent with a second value, and the second value is a value of a remaining quota that is stored in the server. The electronic device calibrates the first parameter based on the first calibration result.

Abstract: A post-processed GNSS solution from raw GNSS data acquired from a vehicle and optionally other sources is dynamically calculated at the epoch level without using a Kalman filter. Instead, a plurality of GNSS processing methods is applied to each epoch in either the forward or backward direction and the most accurate solution for each epoch of the forward generated solution and backward generated solution is combined. The combined post-processed GNSS solution is determined based on which of the GNSS processing methods were used to generate an epoch of the forward solution and a corresponding epoch of the backward solution.

Abstract: A method of integrity monitoring for visual odometry comprises capturing a first image at a first time epoch with stereo vision sensors, capturing a second image at a second time epoch, and extracting features from the images. A temporal feature matching process is performed to match the extracted features, using a feature mismatching limiting discriminator. A range, or depth, recovery process is performed to provide stereo feature matching between two images taken by the stereo vision sensors at the same time epoch, using a range error limiting discriminator. An outlier rejection process is performed using a modified RANSAC technique to limit feature moving events. Feature error magnitude and fault probabilities are characterized using overbounding Gaussian models.

Abstract: Systems and methods for static session multipath detection are described herein. In certain embodiments, a system includes one or more global navigation satellite system (GNSS) receivers configured to receive GNSS signals from multiple GNSS satellites, wherein the GNSS receiver provides GNSS measurements. The system also includes one or more processors configured to receive the GNSS measurements.

Abstract: Systems and methods for GNSS ambiguity resolution are described herein. In some examples, the systems and methods utilize multiple search engines in parallel to validate potential integer candidates for ambiguity resolution using adaptively adjusted residual thresholds.

Abstract: A method of integrity monitoring for visual odometry comprises capturing a first image at a first time epoch with stereo vision sensors, capturing a second image at a second time epoch, and extracting features from the images. A temporal feature matching process is performed to match the extracted features, using a feature mismatching limiting discriminator. A range, or depth, recovery process is performed to provide stereo feature matching between two images taken by the stereo vision sensors at the same time epoch, using a range error limiting discriminator. An outlier rejection process is performed using a modified RANSAC technique to limit feature moving events. Feature error magnitude and fault probabilities are characterized using overbounding Gaussian models.

Abstract: In some examples, a system includes a transceiver configured to receive surveillance messages from Y target vehicles, where Y is an integer greater than two. The system includes processing circuitry configured to determine predicted positions of the Y target vehicles based on the surveillance messages. The processing circuitry is also configured to determine reported positions of the Y target vehicles based on later received surveillance messages. The processing circuitry is further configured to determine that respective differences between the respective predicted position and the respective reported position for X of the Y target vehicles is greater than a threshold distance. The processing circuitry is configured to determine that Global Navigation Satellite System interference has occurred in response to determining that X divided by Y is greater than a threshold level.

Abstract: In some examples, a system includes a transceiver configured to receive surveillance messages from Y target vehicles, where Y is an integer greater than two. The system includes processing circuitry configured to determine predicted positions of the Y target vehicles based on the surveillance messages. The processing circuitry is also configured to determine reported positions of the Y target vehicles based on later received surveillance messages. The processing circuitry is further configured to determine that respective differences between the respective predicted position and the respective reported position for X of the Y target vehicles is greater than a threshold distance. The processing circuitry is configured to determine that Global Navigation Satellite System interference has occurred in response to determining that X divided by Y is greater than a threshold level.

Abstract: Techniques for detecting and excluding spoofed Global Navigation Satellite System (GNSS) signals are described. Using position data acquired from inertial sensors, a line of sight (LOS) estimation can be determined to various satellites. This data can be compared with range data provided by a GNSS receiver, for example, by subtracting the LOS estimations with corresponding GNSS ranges. The difference can then be compared to an appropriate threshold to determine whether GNSS spoofing is present. Additionally, the non-spoofed GNSS signals can be used to generate an updated position solution, which is verified by an integrity algorithm. If verified, the updated position solution can be used to calculate the position of the vehicle. However, if not verified, the disclosed techniques can adjust the thresholds used to determine GNSS spoofing and perform additional iterations of integrity monitoring to acquire a verified positioning solution.

Abstract: Systems and methods for GNSS ambiguity resolution are described herein. In some examples, the systems and methods utilize multiple search engines in parallel to validate potential integer candidates for ambiguity resolution using adaptively adjusted residual thresholds.

Abstract: An unmanned aerial vehicle navigation map construction system based on three-dimensional image reconstruction technology comprises an unmanned aerial vehicle, a data acquiring component and a three-dimensional navigation map construction system, wherein the three-dimensional navigation map construction system comprises an image set input system, a feature point extraction system, a sparse three-dimensional point cloud reconstruction system, a dense three-dimensional point cloud reconstruction system, a point cloud model optimization system and a three-dimensional navigation map reconstruction system. A scene image set is input into the three-dimensional navigation map construction system, feature point detection is carried out on all images, a sparse point cloud model of the scene and a dense point cloud model of the scene are reconstructed, the model is optimized by removing a miscellaneous point and reconstructing the surface, and a three-dimensional navigation map of the scene is reconstructed.

Abstract: An unmanned aerial vehicle navigation map construction system based on three-dimensional image reconstruction technology comprises an unmanned aerial vehicle, a data acquiring component and a three-dimensional navigation map construction system, wherein the three-dimensional navigation map construction system comprises an image set input system, a feature point extraction system, a sparse three-dimensional point cloud reconstruction system, a dense three-dimensional point cloud reconstruction system, a point cloud model optimization system and a three-dimensional navigation map reconstruction system. A scene image set is input into the three-dimensional navigation map construction system, feature point detection is carried out on all images, a sparse point cloud model of the scene and a dense point cloud model of the scene are reconstructed, the model is optimized by removing a miscellaneous point and reconstructing the surface, and a three-dimensional navigation map of the scene is reconstructed.

Abstract: Techniques for detecting and excluding spoofed Global Navigation Satellite System (GNSS) signals are described. Using position data acquired from inertial sensors, a line of sight (LOS) estimation can be determined to various satellites. This data can be compared with range data provided by a GNSS receiver, for example, by subtracting the LOS estimations with corresponding GNSS ranges. The difference can then be compared to an appropriate threshold to determine whether GNSS spoofing is present. Additionally, the non-spoofed GNSS signals can be used to generate an updated position solution, which is verified by an integrity algorithm. If verified, the updated position solution can be used to calculate the position of the vehicle. However, if not verified, the disclosed techniques can adjust the thresholds used to determine GNSS spoofing and perform additional iterations of integrity monitoring to acquire a verified positioning solution.

Abstract: Techniques are described herein for transmitting subgroup messages and displaying such subgroup messages within a group-based message interface. The subgroup message includes both a message intended for the subgroup and a subgroup command indicating that the message is sent to a subgroup of a group participating in a group-based message interface. The subgroup members are then determined from the subgroup command and the subgroup message is displayed to the subgroup members.

Abstract: Approaches presented herein enable displaying a barrage message. Specifically, one or more objects and location information for each object in a frame of a video are identified. A barrage message to be displayed in the frame of the video is obtained. The barrage message is displayed without covering any object in the frame.

Abstract: A pseudo-random noise (PRN) code generator is provided. The PRN code generator includes a register controller; a digitally controlled oscillator (DCO); a primary code generator configured to generate a primary code chip; and a secondary code generator configured to generate a secondary code chip. The primary code generator and the secondary code generator each include: a Weil code generator configured to generate a Weil code chip; a memory code generator configured to generate a memory code chip; a Golden code generator configured to generate a Golden code chip; and a first multiplexer configured to select the Weil code chip, the Golden code chip, or the memory code chip as the primary code chip or the secondary code chip. The PRN code generator also includes a first XOR gate configured to XOR the primary code chip and the secondary code chip to generate a PRN code chip.

Abstract: Techniques are described herein for transmitting subgroup messages and displaying such subgroup messages within a group-based message interface. The subgroup message includes both a message intended for the subgroup and a subgroup command indicating that the message is sent to a subgroup of a group participating in a group-based message interface. The subgroup members are then determined from the subgroup command and the subgroup message is displayed to the subgroup members.

Abstract: A method and apparatus are provided for performing consistency testing for a Bose-Chaudhuri-Hocquenghem (BCH) error corrected first sub-frame of navigation message broadcast from a satellite of a GNSS. Consistency testing is performed by comparing BCH encoded portion(s)s of data symbols with elements of look up table(s) to see if such portions are similar to element(s) of the look up table(s).

Abstract: A pseudo-random noise (PRN) code generator is provided. The PRN code generator includes a register controller; a digitally controlled oscillator (DCO); a primary code generator configured to generate a primary code chip; and a secondary code generator configured to generate a secondary code chip. The primary code generator and the secondary code generator each include: a Weil code generator configured to generate a Weil code chip; a memory code generator configured to generate a memory code chip; a Golden code generator configured to generate a Golden code chip; and a first multiplexer configured to select the Weil code chip, the Golden code chip, or the memory code chip as the primary code chip or the secondary code chip. The PRN code generator also includes a first XOR gate configured to XOR the primary code chip and the secondary code chip to generate a PRN code chip.

Abstract: Approaches presented herein enable displaying a barrage message. Specifically, one or more objects and location information for each object in a frame of a video are identified. A barrage message to be displayed in the frame of the video is obtained. The barrage message is displayed without covering any object in the frame.