Ionosphere grid history and compression for GNSS positioning

A mobile device comprising:

• a Global Navigation Satellite System (GNSS) receiver configured to receive a GNSS signal from a navigation satellite;
• a wireless communication interface configured to communicate with an augmentation system;
• a memory;
• and
• one or more processing units communicatively coupled with the GNSS receiver, the wireless communication interface, and the memory, the one or more processing units configured to:
• determine a positioning measurement of the GNSS signal;
• obtain augmentation data associated with Total Electron Content (TEC) values during one or more prior measurement periods, wherein the one or more processing units are configured to obtain the augmentation data in response to determining that the mobile device is unable to obtain newer augmentation data which is currently stored at the augmentation system;
• obtain a pierce point of the GNSS signal;
• and
• determine an ionospheric error in the positioning measurement of the GNSS signal based on the pierce point and the augmentation data.

A non-transitory computer-readable medium having instructions stored thereon, wherein the instructions, when executed by one or more processing units of a mobile device, cause the one or more processing units to perform the following:

• determining a positioning measurement of a Global Navigation Satellite System (GNSS) signal;
• obtaining, from an augmentation system in wireless communication with the mobile device or from a memory of the mobile device, augmentation data associated with Total Electron Content (TEC) values during one or more prior measurement periods, wherein the obtaining of the augmentation data is performed in response to determining that the mobile device is unable to obtain newer augmentation data which is currently stored at the augmentation system;
• obtaining a pierce point of the GNSS signal;
• and
• determining an ionospheric error in the positioning measurement of the GNSS signal based on the pierce point and the augmentation data.

A computer system comprising:

• a Global Navigation Satellite System (GNSS) receiver configured to receive a GNSS signal from a navigation satellite;
• a wireless communication interface configured to communicate with an augmentation system;
• one or more processing units configured to determine a positioning measurement of the GNSS signal;
• means for obtaining augmentation data associated with Total Electron Content (TEC) values during one or more prior measurement periods, wherein the augmentation data is obtained in response to determining that the computer system is unable to obtain newer augmentation data which is currently stored at the augmentation system;
• means for obtaining a pierce point of the GNSS signal;
• and
• means for determining an ionospheric error in the positioning measurement of the GNSS signal based on the pierce point and the augmentation data.