Control method and control device for link switching

A control method for link switching between a terrestrial base station and a correction satellite for receiving correction data, the control method comprising:

• receiving satellite signals from positioning satellites;
• receiving a current coded signal from the correction satellite according to a main data link, the current coded signal containing correction data;
• determining if a signal quality of current coded signal has reached a predetermined standard, including determining that the signal quality has reached the predetermined standard when the current coded signal is decoded to determine the correction data, and determining that the signal quality has not reached the predetermined standard when the current coded signal cannot be decoded to determine the correction data;
• in response to determining that the signal quality has reached the predetermined standard (i) correcting the satellite signals from the positioning satellites using the correction data from the correction satellite according to the main data link, and (ii) updating an evaluation result to indicate that the current coded signal is reliable;
• and
• in response to determining that the signal quality has not reached the predetermined standard (i) updating the evaluation result to indicate that the current coded signal is unreliable, and (ii) determining if the evaluation result satisfies a predetermined condition,
• when the evaluation result satisfies the predetermined condition (i) maintaining the main data link, and (ii) receiving a subsequent coded signal from the correction satellite to be processed to determine the signal quality, and
• when the evaluation result does not satisfy the predetermined condition (i) establishing an auxiliary data link to the terrestrial base station for receiving the correction data, and (ii) correcting the satellite signals from the positioning satellites using the correction data received from the terrestrial base station,
• wherein the correction data indicates a satellite clock difference, a satellite orbit difference, and/or parameters related to the ionosphere and the troposphere.