topic The Antenna is kept as the same point while captured coordinates keep changing! in ArcPad Questions

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

JamalNUMAN — Sun, 12 Jan 2014 19:28:12 GMT

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

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

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

BrettBlack — Mon, 13 Jan 2014 13:11:12 GMT

What was your estimated positional accuracy? I would assume you did not have a RTK fixed solution at the time so that is why the coordinate values varied.

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

Anonymous User — Thu, 16 Jan 2014 18:12:48 GMT

Original User: Jamal432@gmail.com

What was your estimated positional accuracy? I would assume you did not have a RTK fixed solution at the time so that is why the coordinate values varied.

Many thanks Brett for the help.

Yes I do use the RTK as shown in the screenshot below.

[ATTACH=CONFIG]30580[/ATTACH]

Then how come values do vary?

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

BrettBlack — Thu, 16 Jan 2014 19:36:01 GMT

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.

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

Anonymous User — Thu, 16 Jan 2014 20:08:47 GMT

Original User: Jamal432@gmail.com

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.

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?

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

BrettBlack — Fri, 17 Jan 2014 12:37:52 GMT

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.