GPS status 4 in 3dr ublox GPS. How is it Differential GPS?

When the 3dr ublox GPS module (I have the one with an LEA-6H module) is connected, mission planner shows the GPS status from 1 to 4 with 4 being labelled as 3D dgps. This occurs when the satellite count is over 12. From my understanding of differential GPS, there should be reference base station for differential GPS corrections which are broadcasted to the rover in the case of RTK or post-processed with in the case of PPK. How does the ublox GPS achieve that with just an increase in satellite count? Is the indication an incorrect label? Or Is the Accuracy of the GPS solution increased beyond a certain value that causes it to be labelled as dgps?

Some constellations have 2-3 satellites which emit corrections which are applicable system-wide.
For the GPS system (which you can look up), I think sat. #26 is one of those special ones.

With reception of these satellites you have a slightly enhanced resolution, of ~2m horizontally, instead of ~5m.

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Status 4 is not the same as RTK. Status 4 occurs when the receiver is able to see Satellites that are close to the Horizon. This angle allows it to get a better fix than just seeing the Satellites that are over head.


Actually, @Georacer is right. Status 4 indicates that a WAAS/EGNOS satellite is in sight and the correction data is being used.

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