Currently, only the BeiDou-3 (BDS-3) system supports short message transmission; other satellite systems do not support it.

The accuracy of the GNSS module is actually a probabilistic matter, where 1σ represents 68.3% probability, 2σ represents 95%, and 3σ represents 99.7%.

The height accuracy is twice that of the horizontal accuracy. For instance, if the horizontal accuracy is 2cm, the height accuracy is within 4cm.

When passing through a tunnel, accurate positioning is not possible. For modules with inertial navigation, the position information is calculated based on the previous location data using the gyroscope. Time information can be obtained through self-timing, but the current firmware does not have this functionality.

When passing through a tunnel, accurate positioning is not possible. For modules with inertial navigation, the position information is calculated based on the previous location data using the gyroscope. Time information can be obtained through self-timing, but the current firmware does not have this functionality.