GNSS signal modeling

A Global Navigation Satellite Systems-enabled (GNSS-enabled) device comprising:

• data processing hardware;
• and
• memory hardware in communication with the data processing hardware, the memory hardware storing instructions that when executed on the data processing hardware cause the data processing hardware to perform operations comprising
• receiving an estimated location for a GNSS receiver in an environment;
• generating a plurality of candidate positions about the estimated location for the GNSS receiver, each candidate position of the plurality of candidate positions corresponding to a possible actual location of the GNSS receiver;
• for each available satellite at each candidate position of the plurality of candidate positions, modeling a plurality of candidate signal paths by ray-launching a raster map of geographical data for the environment, the plurality of candidate signal paths comprising one or more reflected signal paths;
• and
• at each candidate position of the plurality of candidate positions:
• comparing the plurality of candidate signal paths modeled for each available satellite at the respective candidate position to measured GNSS signal data from the GNSS receiver;
• and
• generating a likelihood that tire respective candidate position comprises the actual location of the GNSS receiver based on the comparison of the plurality of candidate signal paths modeled for each available satellite at the respective candidate position to the measured GNSS signal data from the GNSS receiver.

A method comprising:

• identifying, by data processing hardware, an area having one or more structures likely to reflect a Global Navigation Satellite Systems (GNSS) signal from a satellite;
• partitioning, by the data processing hardware, the area into a plurality of locations;
• at each location of the plurality of locations for each available satellite:
• generating, by the data processing hardware, a plurality of signal paths by ray-launching from the respective location to the respective available satellite, the plurality of signal paths comprising one or more line of sight signal paths and one or more reflected signal paths;
• discretizing, by the data processing hardware, all reflected signal paths into one or more azimuth ranges;
• for each azimuth range of the one or more azimuth ranges, determining, by the data processing hardware, one or more transition elevations, each transition elevation of the one or more transition elevations corresponding to a degree of elevation that a respective reflected signal path within the respective azimuth range transitions to a line of sight signal, and
• at each location of the plurality of locations, generating, by the data processing hardware, a signal path representation for the plurality of signal paths, the signal path representation comprising;
• the one or more azimuth ranges for all reflected signal paths;
• and
• the one or more transition elevations associated with each azimuth range of the one or more azimuth ranges.

A system comprising;

• data processing hardware;
• and
• memory hardware in communication with the data processing hardware, the memory hardware storing instructions that when executed on the data processing hardware cause the data processing hardware to perform operations comprising:
• identifying an area having one or more structures likely to reflect a Global Navigation Satellite Systems (GNSS) signal from a satellite;
• partitioning the area into a plurality of locations;
• at each location of the plurality of locations for each available satellite:
• generating a plurality of signal paths by ray-launching from the respective location to the respective available satellite, the plurality of signal paths comprising one or more line of sight signal paths and one or more reflected signal paths;
• discretizing all reflected signal paths into one or more azimuth ranges;
• and
• for each azimuth range of the one or more azimuth ranges, determining one or more transition elevations, each transition elevation of the one or more transition elevations corresponding to a degree of elevation that a respective reflected signal path within the respective azimuth range transitions to a line of sight signal;
• and
• at each location of the plurality of locations, generating a signal path representation for the plurality of signal paths, the signal path representation comprising:
• the one or more azimuth ranges for all reflected signal paths;
• and
• the one or more transition elevations associated with each azimuth range of the one or more azimuth ranges.