rtcm3-knowledge-patch

To parse RTCM3 frames, extract the 10-bit payload length, decode the payload, and verify the CRC-24Q checksum to ensure frame integrity for GNSS correction streams. This prevents broken NTRIP connections and RTK failures.

MSM (Multiple Signal Message) and legacy RTCM3 message types differ in payload structure and satellite observation handling. MSM offers detailed phase and range data with subtypes like MSM4 and MSM7, whereas legacy types provide basic GPS, GLONASS, Galileo, and BDS observations.

Setting up an NTRIP v2 client connection involves handling authentication, querying the sourcetable for available streams, and sending VRS/GGA position data to the caster to receive RTK corrections properly.

Timestamp alignment issues causing 1 ms errors in RTK workflows stem from incorrect payload decoding or SSR phase interpretation. Validating the 12-bit message type and applying timestamp alignment fixes ensures accurate RTK and PPP corrections.

Yes, this RTCM3 parsing approach supports multiple GNSS constellations including GPS, GLONASS, Galileo, and BDS. It handles both MSM and legacy message type ranges specific to each constellation for comprehensive correction stream integration.

Legacy RTCM3 messages lack the high-resolution phase and range data density found in MSM formats. Using legacy types limits SSR phase interpretation and timestamp alignment precision, making MSM4 or MSM7 better for advanced RTK and PPP workflows.