# RTCM RTCM (Radio Technical Commission for Maritime) is a protocol that supports transferring a variety of correction messages from a base station to a rover (or in our case a drone). In an [RTK](/drone-show-technology/gps-gnss/rtk-gps.md)-enabled [GNSS](https://wiki.droneshow.software/index.php?title=GNSS\&action=edit\&redlink=1) system, RTCM data must be regularly generated/transmitted by the base station and received by the rover to attain cm-level accuracy. Data is sent at roughly 1 Hz, or once per second. If an RTCM stream is lost, [GNSS](https://wiki.droneshow.software/index.php?title=GNSS\&action=edit\&redlink=1) accuracy will degrade until standard 3D-Fix is reached (\~3 meters). This is well beyond the inter-drone distance used during show design, so a loss of RTCM can result in collisions. If you've ever seen a drone show look "fuzzy" or chaotic, then it is most likely due to a loss of RTCM. ### Data Transfer In Verge Aero's system, RTCM data is transmitted via high-reliability link. As this is the only data stream that is absolutely necessary during an active drone show, using a low-bandwidth, high-reliability link maximizes the likelihood of successful reception. RTCM data is *also* optionally sent over the primary gateway, however it requires that a [Verge Aero Console](/drone-show-software/verge-console.md) be connected and active. Having multiple radio paths improves the system's robustness. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.verge.aero/drone-show-technology/gps-gnss/rtcm.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.