Hi @zep,
Welcome to our forum!
Let’s break this down into key parts.
- Float vs Fix
Float solution status means the rover receives corrections from the base but can’t resolve all ambiguities. Its accuracy usually ranges from several decimeters to 1-2 meters. Fix means the receiver resolved ambiguities in the position calculation. It usually has centimeter-level accuracy.
While some FLOAT points may appear accurate, others can be significantly off, as you’ve observed. So, a Fix solution is preferred for high-accuracy applications.
- RMS
It’s the average deviation of your survey points from the actual position. Lower RMS error means your data is generally more accurate—like scoring closer to the bullseye in a target game.
- Satellite Geometry:
PDOP shows the quality of satellite geometry. High DOP means poor geometry when the satellites are too close to each other in the field of view. The lower the DOP, the more accurate your data is. Ideally, aim for a DOP value below 2.
Possible reasons for getting FLOAT points:
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Environmental conditions: The GNSS receiver calculates a solution based on the signals it receives from the satellites. When they are blocked by obstacles nearby, such as trees, it becomes harder for the unit to resolve all the ambiguities in its position and provide you with an accurate solution. That’s why we recommend following recommendations from this guide for the receiver placement.
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Corrections stream: You need to ensure a stable internet connection while using an NTRIP. You can find what else is worth checking from the NTRIP service’s side in our support tip.
RTK (Real-Time Kinematic) offers immediate centimeter-level accuracy using real-time corrections from a base station. PPK (Post-Processed Kinematic) involves recording raw data during the survey and processing it later in Emlid Studio. So, you can still get similar high accuracy without needing real-time corrections.
@timd1971, thanks for sharing the link! I believe our guides will provide further helpful details.