topic Re: Differential correction of GPS data in state plane in ArcPad Questions

Differential correction of GPS data in state plane

deleted-user-5rGCC1WKrhju — Tue, 31 Aug 2010 12:02:00 GMT

I'm trying to differentially correct some GPS data for a co-worker but am running into some issues. I have a shapefile and GPScorrect.ssf file she collected. When creating a geodatabase to do the correction in I have to set up a transformation since the shapefile is projected in NAD_1983_StatePlane_Maryland_FIPS_1900_Feet.

Eventually the shapefile and .ssf file import correctly, but when I go through the motions to do the actualy correction I run into a road block. When I get to the section to select a base provider it comes up blank and won't search for a new base station. Any ideas?

Running ArcGIS 9.3.1 SP2 & GPS-Analyst

Adam Babarsky
Senior GIS Technician
US Army IGI&S Support Center

Re: Differential correction of GPS data in state plane

deleted-user-5rGCC1WKrhju — Tue, 31 Aug 2010 12:18:08 GMT

Figured it out!

I had selected "Automatic H-Star Carrier and Code Processing" instead of "Standard Code Processing Only"

Doh!

Re: Differential correction of GPS data in state plane

ericbock — Thu, 16 Sep 2010 19:44:31 GMT

Adam,

If you have a GeoXH then you want to choose the Automatic H-star Carrier and Code Processing in order to achieve subfoot accuracies. You were on the right track, however you need to create a group and add stations to the group (choose select, new, add +). 1 station within 50 miles or 3 or more within 125 miles. I find better accuracies with 3 stations spread out around the data. You could be degrading the accuracy of your data when using Standard Code Processing with a Trimble H-star receiver.

Good Luck

Re: Differential correction of GPS data in state plane

kyledavies — Mon, 20 Sep 2010 20:32:40 GMT

I am having major issues trying to post-process/differentially correct edited data I created in ArcPad8

I am using the trimble gps analyst extension in arcmap to load my data into a trimble Juno SB GPS unit.

My geodatabase and feature classes I edited are GPS-enabled and the projected coord. system is nad83 nc statepalne 3200, geographic coord system = GCS_north American_ 1983. I then select 'get data for arcpad' on the trimble gps analyst toolbar in arcmap. I then edited my data in the field.

When checking data back in. I have been using the 'check in arcpad axf file and gpscorrect ssf ' tab beacuse the 'check in arcpad shapefile and gpscorrect ssf ' is "greyed out." Once it has given me an error message saying I need to add the tool in arctoolbox. Another time I got all the way to where I am selecting base data for differential collection but when the process runs it says my file is empty or corrupted.

Can anyone help me? Am I setting my data up wrong before exporting to the gps unit? Or am i doing something wrong in my post processing steps? both?