PaulZC
October 22, 2025, 10:44am
4
OK - thank you.
It may be due to the position and orientation of the satellites in the sky, on that particular day at that particular time. Please see the post below for more information. +/-0.5cm is very close to what is possible with RTK. If a tolerance of +/-1cm works better, I would suggest using that.
Best wishes,
X, Y, and Z accuracies are in that order typically. Your X component is generally the best, Z is the worst. There are many reasons for this, but most stem from the fact that Positioning relies on the principle of trilateration.
When you think about the orientation of satellites (birds) flying around overhead, the Z component is the most sensitive to errors in the trilateration calculations. The best birds for calculating a single distance are directly overhead, and the worst are low on the horizon. Geometry would point us to adding the birds low on the horizon to better “fix” a point in 3D space - but those signals must travel through more atmosphere than the rest. Low angles are also much more susceptible to Multi-Path interference at the receiver.
Now consider that the bird has traveled a couple hundred miles [Correction: meters] through space during the time it takes the RF signal to reach Earth. Plus the Earth is spinning and the Y coordinate has moved ~100’ during that ti…
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