Positioning device and positioning method

A positioning device comprising:

• a processor to execute a program;
• and
• a memory to store the program which, when executed by the processor, performs processes of,
• acquiring a position, a velocity, and an azimuth of a vehicle, Raw data, and a positioning augmentation signal from a global navigation satellite system (GNSS) receiver, the position, the velocity, and the azimuth of the vehicle being calculated from radio waves received from at least four GNSS satellites and the positioning augmentation signal received from a positioning augmentation satellite, the Raw data being extracted from the radio waves of the at least four GNSS satellites;
• calculating a position of the vehicle by dead reckoning;
• smoothing a pseudorange between each of the at least four GNSS satellites and the vehicle using a carrier wave phase included in the Raw data, the pseudorange being included in the Raw data;
• evaluating reliability of the position of the vehicle calculated by the GNSS receiver;
• conducting GNSS positioning to calculate a position of the vehicle from a smoothed value of the pseudorange, the positioning augmentation signal, an orbit of the GNSS satellite, and an evaluation result of the reliability of the position of the vehicle calculated by the GNSS receiver;
• conducting complex positioning to calculate an error in the dead reckoning from the position of the vehicle calculated by the GNSS positioning and to correct the position of the vehicle calculated by the dead reckoning based on the error in the dead reckoning;
• and
• outputting a corrected position of the vehicle which is corrected by the complex positioning,
• wherein the processor, in the complex positioning, calculates an error in the dead reckoning in a past epoch from a history of the position of the vehicle calculated by the dead reckoning and a history of the position of the vehicle calculated by the GNSS receiver and corrects the history of the position of the vehicle calculated by the dead reckoning and a latest position of the vehicle calculated by the dead reckoning based on the error in the dead reckoning in the past epoch.