Path planning using forecasts of obscuration and multipath

A method used by a flight control system with GNSS Forecasts and planned paths or routes for a plurality of flying vehicles, including:

• requesting the GNSS Forecast of signal obscuration on behalf of a flying autonomous or automated vehicle travelling in a region;
• receiving the requested GNSS Forecast for obscuration of GNSS satellites from 3D cuboids;
• wherein the GNSS Forecast depends on whether lines-of-sight from the vehicle to GNSS satellites will be blocked by surrounding structures during a certain time frame for which the lines of site are predicted;
• and
• using the GNSS Forecast to plan a path or route in response to the GNSS Forecast of line-of-sight signals available over the path or route that satisfy predetermined criteria including space to accommodate real-time changes in flight paths, varying from the planned path or route, without compromising a diverted flying vehicle's ability meet requirements of flight control in an airspace.

A method of collecting and recording for playback GNSS signals as a function of location, altitude, and flight envelope, including:

• flying a vessel equipped with a GNSS signal recorder over a controlled urban landscape and collecting data regarding actual signals received from individual satellites;
• comparing the actual signals received to a GNSS Forecast covering a time and location of operation of a GNSS receiver, including a predicted reliability measure for respective GNSS signals received from the individual satellites;
• wherein the GNSS Forecast depends on whether lines-of-sight from the vehicle to GNSS satellites will be blocked by surrounding structures during a certain time frame for which the lines of site are predicted;
• updating a model used to generate the GNSS Forecast;
• and
• using the updated model to generate subsequent GNSS Forecasts.

A method of certifying performance of GNSS receivers used on a flying vessel, including:

• flying a vessel equipped with a GNSS signal recorder over a controlled urban landscape and collecting data regarding actual signals received, while collecting data regarding determination by a GNSS receiver onboard the vessel of position of the vessel;
• comparing the actual signals received and the determined position to external sensor recordings of a path of the flying vessel;
• and
• based at least in part on the comparing, certifying performance of the GNSS receiver when the comparing shows a correlation between the received GNSS signals and predicted GNSS signals and between the determined position and the external sensor recordings of the path within a predetermined tolerance;
• wherein the predicted GNSS signals include prediction whether lines-of-sight from the vehicle to GNSS satellites will be blocked by surrounding structures during a certain time frame for which the lines of site are predicted.