Method and apparatus for in motion initialization of global navigation satellite system - inertial navigation system

A mobile device in a vehicle, the mobile device configured to support in-motion calibration of a Global Navigation Satellite System (GNSS)-Inertial Navigation System (INS) system in the mobile device, the mobile device comprising:

• an inertial measurement unit comprising an accelerometer and a gyroscope;
• a GNSS receiver;
• at least one memory;
• at least one processor coupled to the inertial measurement unit and the GNSS receiver and the at least one memory, wherein the at least one processor is configured to:
• determine a gravity vector based on gyroscope measurements while the vehicle is turning;
• determine a forward vector based on the gravity vector and accelerometer measurements while the vehicle is traveling straight;
• determine a north vector based on GNSS measurements of a heading angle;
• and
• initialize a GNSS-INS filter using the gravity vector, the forward vector and the north vector.

A method of in-motion calibration of a Global Navigation Satellite System (GNSS)-Inertial Navigation System (INS) system in a mobile device in a vehicle, the method comprising:

• determining a first orientation of the mobile device with respect to a global reference frame based on a previous calibration of a GNSS-INS filter;
• detecting an indication that the mobile device has moved with respect to the vehicle;
• determining a second orientation of the mobile device with respect to the global reference frame based on an in-motion calibration of the GNSS-INS filter while the vehicle is moving;
• comparing the first orientation and the second orientation;
• and
• using the first orientation for the GNSS-INS filter to produce a position and heading based on the first orientation if a difference between the first orientation and the second orientation is below a threshold and using the second orientation for the GNSS-INS filter to produce the position and heading based on the second orientation if the difference between the first orientation and the second orientation is above the threshold.

A mobile device in a vehicle, the mobile device configured to support in-motion calibration of a Global Navigation Satellite System (GNSS)-Inertial Navigation System (INS) system in the mobile device, the mobile device comprising:

• an inertial measurement unit comprising an accelerometer and a gyroscope;
• a GNSS receiver;
• at least one memory;
• at least one processor coupled to the inertial measurement unit and the GNSS receiver and the at least one memory, wherein the at least one processor is configured to:
• determine a first orientation of the mobile device with respect to a global reference frame based on a previous calibration of a GNSS-INS filter;
• detect an indication that the mobile device has moved with respect to the vehicle;
• determine a second orientation of the mobile device with respect to the global reference frame based on an in-motion calibration of the GNSS-INS filter while the vehicle is moving;
• compare the first orientation and the second orientation;
• and
• use the first orientation for the GNSS-INS filter to produce a position and heading based on the first orientation if a difference between the first orientation and the second orientation is below a threshold and using the second orientation for the GNSS-INS filter to produce the position and heading based on second orientation if the difference between the first orientation and the second orientation is above the threshold.