Abstract: The disclosed technology teaches testing an autonomous vehicle: shielding a GNSS receiving antenna of the vehicle from ambient GNSS signals while the vehicle is under test and supplanting the ambient GNSS signals with simulated GNSS signals. Testing includes using a GNSS signal generating system: receiving the ambient GNSS signals using an antenna of the system and determining a location and acceleration of the vehicle from the GNSS signals, accessing a model of an augmented environment that includes multi-pathing and obscuration of the GNSS signals along a test path, based on the determined location—generating the simulated GNSS signals to feed to the vehicle, in real time—simulating at least one constellation of GNSS satellite sources modified according to the augmented environment, based on the determined location, and feeding the simulated signals to a receiver in the vehicle, thereby supplanting ambient GNSS as the autonomous vehicle travels along the test path.

Abstract: Disclosed is a method of providing DOP forecasts for LEO navigation for routing of vehicles, aircraft, alerting humans in vehicles, or wireless devices, and bandwidth forecasts for LEO communications. The method includes accessing a 3D map of an area including structure solids and generating cuboids in spaces not contained in the structure solids; and iteratively over time increments, calculating LEO satellites visible from the cuboids using the map and, using at least the calculated visibility, determining forecasts for the cuboids at the time increments. Also included is compressing the determined forecast spatially and temporally; and distributing the compressed DOP forecast via a CDN, responsive to queries from requestors. Systems of the requestors can take into account the forecast for routing vehicles or alerting humans in vehicles to a predicted navigation impairment. Risk analysis is applied to improving computation and distribution of forecasts. Forecasts are applied to satellite deployment.

Abstract: Disclosed is a method of providing DOP forecasts for LEO navigation for routing of vehicles, aircraft, alerting humans in vehicles, or wireless devices, and bandwidth forecasts for LEO communications. The method includes accessing a 3D map of an area including structure solids and generating cuboids in spaces not contained in the structure solids; and iteratively over time increments, calculating LEO satellites visible from the cuboids using the map and, using at least the calculated visibility, determining forecasts for the cuboids at the time increments. Also included is compressing the determined forecast spatially and temporally; and distributing the compressed DOP forecast via a CDN, responsive to queries from requestors. Systems of the requestors can take into account the forecast for routing vehicles or alerting humans in vehicles to a predicted navigation impairment. Risk analysis is applied to improving computation and distribution of forecasts. Forecasts are applied to satellite deployment.

Abstract: The disclosed technology for preparing digital samples for synthesis of RF to simulate channels and GNSS satellites using GPUs includes receiving simulated position and velocity of an antenna, dividing the cycle into points to be converted into the synthesized signal, and computing the points. A first LUT includes pseudo random sequences combinable to produce a code that varies over time for encoding the channel, and a second LUT specifies linear combinations of the pseudo random sequences in the first LUT that produce channel codes to produce the digital sample points. Also included is using GPUs to generate the channel code for a point by mapping the channel code and time position, combining the code with data to be encoded, repeatedly applying the using and combining to produce points, using multiple GPU cores to encode sample points concurrently in the cycle, and sending an ordered sequence of points to a converter.

Abstract: Disclosed is incorporating an IQ stream into a test signal for a receiver in motion, configuring a path for the motion of the receiver during simulation, a period of the simulation, a transmitter constellation to emulate, and a path of at least one IQ stream transmitter. Also generating signals emulating the transmitter constellation and conditioning the stream to be merged with the signals, using distance and relative motion between receiver and transmitter to determine delay and Doppler shift between transmitter and receiver in motion, scheduling sampling of the signal, including interpolation among samples of the stream, based on delay and Doppler shift, and synthesizing a conditioned stream from the interpolation between the samples, taking into account signal level of the stream, in addition to delay and shift, and merging the conditioned signal with the signals emulating the transmitter constellation and supplying the merged signals to the receiver during the test.

Abstract: Disclosed is a method of enhancing RTK position resolution using an RTK-enabled GNSS positioning receiver, including receiving an RTK base station signal for differential position calculation, and receiving a forecast assured navigation signal that includes data identifying line-of-sight availability of satellites generating GNSS signals at a position of the GNSS positioning receiver. Also included is excluding from, or reducing the weighting of, GNSS position calculation satellites not identified as line-of-sight available in the forecast assured navigation signal, and computing the GNSS position calculation combining the knowledge of line of sight, or not line of sight, satellites with the RTK base station signal to perform the differential position calculation and to determine an improved calculated position of the GNSS positioning receiver.

Abstract: The technology disclosed teaches a method of improving accuracy of a GNSS receiver that has a non-directional antenna, with the receiver sending CDN a request for predictive data for an area that includes the receiver. Responsive to the query, the method includes receiving data regarding LOS visibility for the receiver with respect to individual satellites, and the receiver using the data for satellite selection, for choosing some and ignoring other individual satellites. Also disclosed is using the data to exclude from satellite selection at least one individual satellite based on lack of LOS visibility to the individual satellite. Further disclosed is recognizing and rejecting spoofed GNSS signals received by a GNSS receiver that has a non-directional antenna, in response to a CDN response to a request for predictive data for an area that includes the receiver, with the receiver comparing the data with measures of signals received from individual satellites.

Abstract: The technology disclosed teaches a method of improving accuracy of a GNSS receiver that has a non-directional antenna, with the receiver sending CDN a request for predictive data for an area that includes the receiver. Responsive to the query, the method includes receiving data regarding LOS visibility for the receiver with respect to individual satellites, and the receiver using the data for satellite selection, for choosing some and ignoring other individual satellites. Also disclosed is using the data to exclude from satellite selection at least one individual satellite based on lack of LOS visibility to the individual satellite. Further disclosed is recognizing and rejecting spoofed GNSS signals received by a GNSS receiver that has a non-directional antenna, in response to a CDN response to a request for predictive data for an area that includes the receiver, with the receiver comparing the data with measures of signals received from individual satellites.

Abstract: The disclosed technology teaches simulating new satellite messages for a GNSS simulation, providing a configuration file and programming script file, neither of which is pre-compiled into GNSS simulation code, that specify format for a message for a satellite and message format combination not yet operational or not yet compiled into the GNSS simulation code. Included is reading and applying the configuration file and running a script from the programming script file to generate navigation data for simulating positioning messages during the GNSS simulation and using the navigation data for simulating positioning signals during the GNSS simulation and testing of a GNSS receiver against the satellite and message format combination. The disclosed technology also teaches determining message format and values to use when simulating position signals by combining field format and field data values from a combination of the configuration files, almanac, ephemeris and related data, and the programming script files.

Abstract: Disclosed is reducing starting time for a GNSS receiver that has an imprecise initial starting location by requesting starting assistance from a CDN that caches predictive data including first data indicated predicted LOS visibility from the receiver to individual satellites, wherein the request includes the imprecise initial staring location, receiving, from the CDN, data that includes a first block of the predictive data for the imprecise initial staring location and further adjoining second blocks of predictive data for areas surrounding the imprecise staring location, determining, by the GNSS receiver, commonly available satellites that have visibility from locations in both the first block and the second block, and calculating a first starting position using weighted values for the satellites, the commonly available satellites having higher weighted value than satellites without visibility in both locations, whereby position uncertainty of the first starting position is reduced from the imprecise initial

Abstract: Disclosed is representing distant objects for analysis of satellite line-of-sight visibility from a grid of points by constructing a first 3D model of foreground objects that obscure line-of-sight visibility of satellites from a grid of points, wherein the first 3D model is at a first resolution, where spacing of grid points denotes obstruction edges, constructing a second 3D model of background objects that are more than a threshold distance away and that object obscure line-of-sight visibility of satellites from the grid of points, wherein the second 3D model is at a second resolution that is different from and coarser than the first resolution, calculating a line-of-sight visibility of the satellites from the grid of points using a combination of the first and second 3D models, and responding to a query for an area by providing the calculated line-of-sight visibility of the satellites for points of the grid within the area.

Abstract: Disclosed is determining GNSS satellite position visibility by possessing an orbital segment representing the transit of a satellite in orbit over time, a coarse ray angle interval, a fine ray angle interval, and a digital surface model. Disclosed is propagating coarse ray at coarse ray angle intervals increments in a first pass between an observable point and orbital segment at a respective coarse ray angle to determine whether the coarse ray is obstructed by features of the DSM, and recording a status of the coarse ray based on whether the coarse ray was obstructed. If pairs of successive coarse rays have different status, designating the coarse ray with NLOS visibility, then performing a second pass by propagating, per each designated coarse ray, fine rays at fine ray angle intervals, and saving an indication of time at which LOS visibility to the satellite is obstructed.

Abstract: Disclosed is a method of detecting and rejecting a spoofing or jamming signal source by receiving at a first device a forecast of a visibility for each Global Navigation Satellite System (GNSS) satellite signal source in the forecast at a GNSS receiver coupled to the first device, calculating from at least an elevation and the received visibility of the satellite signal sources in the forecast a predicted Signal to Noise Ratio (SNR), comparing SNR acquired by the GNSS receiver of one or more of the satellite signal sources to the predicted SNR, detecting a spoofing signal source based on acquiring a higher SNR than predicted or a jamming signal source based on acquiring a lower SNR than predicted, and rejecting the spoofing or jamming signal source based on differences between the acquired and predicted SNR.

Abstract: Disclosed is route planning using a worst-case risk analysis and, if needed, a best-case risk analysis of GNSS coverage. The worst-case risk analysis identifies cuboids or 2d regions through which a vehicle can be routed with assurance that adequate GNSS coverage will be available regardless of the time of day that the vehicle travels. The best-case risk analysis identifies cuboids or 2d regions through which there is adequate coverage at some times during the day. In case path finding using the worst-case risk analysis fails, a best-case risk analysis can be requested and used to find alternate potential path(s). Time dependent forecast data that covers regions along the alternate potential path(s) can be requested and used to route vehicles, including autonomous drones, from starting points to destinations. This includes generation, distribution and use of risk analysis data, implemented as methods, systems and articles of manufacture.

Abstract: The technology disclosed teaches a method of path planning using a GNSS Forecast, requesting the GNSS Forecast of signal obscuration on behalf of a vehicle travelling in a region, receiving and using the Forecast to plan a path or route that has GNSS signals available over the path or route that satisfy a predetermined criterium. Also taught are GNSS Forecasts and planned paths or routes for a plurality of flying vehicles used by a flight control system, requesting the GNSS Forecast of signal obscuration on behalf of a flying autonomous or automated vehicle travelling in a region, receiving and using the Forecast and to plan a path with GNSS signals available over the path that satisfy predetermined criteria including accommodating real-time changes in flight paths, without leaving space, that satisfies the predetermined criteria. Also taught is certifying performance of GNSS receivers used on a flying vessel.

Abstract: The disclosed technology for preparing digital samples for synthesis of RF to simulate channels and GNSS satellites using GPUs includes receiving simulated position and velocity of an antenna, dividing the cycle into points to be converted into the synthesized signal, and computing the points. A first LUT includes pseudo random sequences combinable to produce a code that varies over time for encoding the channel, and a second LUT specifies linear combinations of the pseudo random sequences in the first LUT that produce channel codes to produce the digital sample points. Also included is using GPUs to generate the channel code for a point by mapping the channel code and time position, combining the code with data to be encoded, repeatedly applying the using and combining to produce points, using multiple GPU cores to encode sample points concurrently in the cycle, and sending an ordered sequence of points to a converter.

Abstract: The disclosed technology teaches simulating new satellite messages for a GNSS simulation, providing a configuration file and programming script file, neither of which is pre-compiled into GNSS simulation code, that specify format for a message for a satellite and message format combination not yet operational or not yet compiled into the GNSS simulation code. Included is reading and applying the configuration file and running a script from the programming script file to generate navigation data for simulating positioning messages during the GNSS simulation and using the navigation data for simulating positioning signals during the GNSS simulation and testing of a GNSS receiver against the satellite and message format combination. The disclosed technology also teaches determining message format and values to use when simulating position signals by combining field format and field data values from a combination of the configuration files, almanac, ephemeris and related data, and the programming script files.

Abstract: Disclosed is a method of enhancing RTK position resolution using an RTK-enabled GNSS positioning receiver, including receiving an RTK base station signal for differential position calculation, and receiving a forecast assured navigation signal that includes data identifying line-of-sight availability of satellites generating GNSS signals at a position of the GNSS positioning receiver. Also included is excluding from, or reducing the weighting of, GNSS position calculation satellites not identified as line-of-sight available in the forecast assured navigation signal, and computing the GNSS position calculation combining the knowledge of line of sight, or not line of sight, satellites with the RTK base station signal to perform the differential position calculation and to determine an improved calculated position of the GNSS positioning receiver.

Abstract: The disclosed technology teaches simulating new satellite messages for a GNSS simulation, providing a configuration file and programming script file, neither of which is pre-compiled into GNSS simulation code, that specify format for a message for a satellite and message format combination not yet operational or not yet compiled into the GNSS simulation code. Included is reading and applying the configuration file and running a script from the programming script file to generate navigation data for simulating positioning messages during the GNSS simulation and using the navigation data for simulating positioning signals during the GNSS simulation and testing of a GNSS receiver against the satellite and message format combination. The disclosed technology also teaches determining message format and values to use when simulating position signals by combining field format and field data values from a combination of the configuration files, almanac, ephemeris and related data, and the programming script files.

Abstract: A method is provided for calibrating a test platform including a plurality of system outputs to align RF signals generated by the system outputs. RF power of a combined RF signal is detected, where the combined RF signal is from a reference RF signal generated by a reference system output in the plurality of system outputs and a test RF signal generated by a test system output in the plurality of systems outputs. A phase of the test RF signal is iteratively shifted relative to the reference RF signal until the detected RF power reaches a minimum. The test RF signal is inverted to be in-phase with the reference RF signal when the combined RF power reaches the minimum. A system is also provided for calibrating a test platform including a plurality of system outputs to align RF signals generated by the system outputs.