@Curtis Elliott yeah that's a really valid concern and you're right to be suspicious — that quiet downsampling behavior is frustratingly common, especially on cheaper u-blox-based modules where the RMC or VTG sentences get clocked at a lower rate than GGA even though the marketing says "18Hz."
Honest answer: I don't have the full datasheet in front of me right now to confirm definitively whether the GNSS module outputs RMC/VTG at the full 18Hz alongside the position fix, so I don't want to guess and send you down the wrong path. What I'd do is post this directly in the Dev Hub and tag Moamen — he's the one who designed it and will know exactly how the NMEA message scheduling is configured at the firmware level, and whether there's any rate configuration available if the defaults don't match what you need.
What I can say is that 18Hz is specifically called out as a differentiator for fast-moving platforms, so the intent is clearly to support exactly your use case — but whether that's position-only or full NMEA sentence output at that rate is a config detail worth confirming before you build your dead reckoning logic around it.
