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Beginning. Basic step-by-step demonstration for: Obtaining Basefile from CORS or local GPS web sites Using basefiles for Differential Correction of Trimble Rover files (.ssf) using Pathfinder Office. overview.
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Beginning • Basic step-by-step demonstration for: • Obtaining Basefile from CORS or local GPS web sites • Using basefiles for Differential Correction of Trimble Rover files (.ssf) using Pathfinder Office
overview Differential correction compares and corrects your Rover file using a Base file, from a stationary base station receiver (at a known location) for the exact same time as your Rover file. The first step is to obtain a base file. The most common source are CORS web sites. Even though we may not use a CORS site, it is important to be familiar with the CORS format…
Use skagit instead HOWEVER: For local GPS work (within Whatcom County), the Skagit County GPS base station is supperior: Closer 5 second sampling interval (Whidbey CORS is 30 second) So… use their site instead
15 zip file Double click to open
17 extract to base Extract to C:/Pfdata/default/base folder
18 base file Base file in Base folder…
Pathfinder Now, having downloaded a base file for the correct time period, a Rover file can be corrected using Pathfinder office…
1 Windows Open Pathfinder office
19 Pathfinder Add your GPS data
19 open Rover file Open Uncorrected Rover file in Pathfinder
19 Opened file Uncorrected Rover file
20 Util Differentially correct your Rover file using the corresponding base file
wait Wait for the Differential Correction window to open… for some reason this seems to take a few minutes.
25 smart code ok Use Smart Code and Carrier Phase Processing
27 open files Compare corrected and uncorrected files
28 Open both files Open both original Uncorrected rover file And corrected file for comparison.
29 zoom Drag a box with zoom tool
30 close up of both Compare the two files…
Export ‘em Both the uncorrected Rover file and the corrected file can be exported to ArcView shapefiles for GIS use and spatial analysis… (see GPS_PF-AV_demo.ppt…)
fini fini