TraceRouter is our NTRIP caster responsible for routing correction streams from multiple sources. It manages which data streams are sent to each client based on configuration rules and the client’s current state. For instance, it automatically transitions a rover’s connection between the Ephemeris and VRTK streams by interpreting NMEA GGA messages received from the client.
Subscribe to /assist stream and repeat ephemerides every 5 s
VRTK mode
First valid GGA received
Switch to nearest VRS mountpoint, stream MSM4 corrections
Re-evaluate
GGA location change beyond cell bounds
Seamlessly hand off to new region/base
Disconnect
TCP closed or timeout
Release resources, log usage metrics, trigger alerts if configured
TraceRouter tolerates short GGA gaps. Before the first GGA arrives, the rover has up to 10 minutes to achieve a fix. After promotion to VRTK, the session expects the client to send a GGA message at least every 30 seconds or the connection is dropped.