Question

To achieve centimeter-level accuracy with RTK-GPS, what specific data must the ground base station transmit to the drone in real-time?

Accepted Answer

To achieve centimeter-level accuracy, the ground base station must transmit its precise, known geographic coordinates and the raw carrier-phase observations of the satellite signals it is receiving. Because the base station occupies a fixed, surveyed location, it calculates the difference between its known position and the position it currently perceives based on satellite signals. This difference is called the correction data. The base station transmits this data to the drone via a radio or cellular link, typically using the RTCM (Radio Technical Commission for Maritime Services) standard format. The drone uses these corrections to offset the errors in its own satellite signal reception, which are primarily caused by atmospheric interference in the ionosphere and troposphere and inaccuracies in satellite orbital data. By applying these corrections to its own raw measurements in real-time, the drone transitions from standard GPS accuracy of several meters to centimeter-level positioning by resolving the ambiguity of the carrier-phase waves. Carrier-phase refers to the specific electromagnetic wave cycles transmitted by satellites, which provide much higher precision than simple code-based timing. The drone&#x27;s onboard processor uses these corrected measurements to solve for its position relative to the base station, effectively canceling out the common errors shared by both receivers.

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To achieve centimeter-level accuracy with RTK-GPS, what specific data must the ground base station transmit to the drone in real-time?