Introduction
In GNSS, accuracy and precision are related, but they are not the same.
Accuracy is how close a reported position is to the true location.
Precision is how closely repeated position results match each other over time.
A receiver can be precise if it gives nearly the same result again and again, even if that result is slightly offset from the true position. It can also be reasonably accurate on average, but not very precise if the reported points are spread out.
In most GNSS applications, both matter. The ideal result is a position that is both correct and repeatable.
How PointPerfect helps
PointPerfect provides correction data that helps reduce common GNSS errors. With a compatible receiver, this can improve accuracy by moving the reported position closer to the true location and improve precision by reducing position scatter.
How to test a GNSS receiver
A simple stationary test can be used on almost any GNSS receiver.
Place the receiver in a fixed location with a clear view of the sky and do not move it during the test. Record position data for a meaningful period of time. If possible, test once without corrections and once with PointPerfect enabled.
To check precision, look at how tightly the recorded points cluster together. A tighter cluster means better repeatability.
To check accuracy, compare the average measured position to a known reference point, such as a surveyed location or another trusted coordinate. The reference point must be in the same reference frame as the GNSS output. If it is not, an offset may appear even when the receiver is performing correctly. When needed, a reference frame transformation should be applied before comparing the results.
Summary
Accuracy is how close the position is to the true location.
Precision is how repeatable the position results are.
Testing with and without PointPerfect is a simple way to see how GNSS corrections can improve both.