The Antenna is kept as the same point while captured coordinates keep changing!

Question

I�??m using Leica CS25 GPS (GG03 Antenna + Zeno Field software + RTK), nevertheless, the captured point keeps changing despite the fact that the antenna is kept at the same point

[ATTACH=CONFIG]30426[/ATTACH], [ATTACH=CONFIG]30427[/ATTACH]

My understanding that the differential GPS (Leica CS25) has -/+ 2cm as accuracy

What might be the issue here?

Thank you

Best

Jamal

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BrettBlack · Answer

Jamal,

There are a lot of unknowns about your network, how you are configuring your project, ArcPad/Zeno Field, etc. You had mentioned prior that you are modifying the GPS datum in Zeno Field, which is not recommended as all transformations are handled by Zeno Office/Zeno Office on ArcGIS. Also, what coordinate system is your GPS reference network sending the corrections in?

I would highly recommend some level of training (on-site or web-based) as I do not experience any of the difficulties that you have to date. When I connect to a local real-time network (RTCM3_IMAX mountpoint), receive RTK corrections to 1 cm and check into a control monument with established coordinates I check well within the GNSS accuracy stated by the GG03.

If you set the GG03 up on a known point, are receiving RTK corrections to a phase-fixed 1 cm solution and are not moving while storing 3 separate points, all three of the X, Y, Z values of these survey points in Zeno Office/Zeno Office on ArcGIS should be in the centimeter range. If not, you have a configuration issue.

Anonymous User · Answer

Original User: Jamal432@gmail.comIf receiving RTK corrections and my estimated positional error is at 1 cm then my coordinate values are all well within specification. You should compare your X, Y, Z values.

Thanks Brett.

This is the issue.

How come while I�??m having RTK corrections and still the value captured at a particular point varies with a difference that exceeds the accuracy (1 cm)?

Why the captured XYZ varies while the antenna is fixed on the same point?

BrettBlack · Answer

If receiving RTK corrections and my estimated positional error is at 1 cm then my coordinate values are all well within specification. You should compare your X, Y, Z values.