GPS Data Handling Procedures During CAMEX-III

I. Transferring data from the Trimble data logger

What:  Transfer data from the Trimble datalogger to the IBM Thinkpad 755CE.
When:  Daily anytime after 8pm (0:00 UTC)
Why:  The Trimble stores the data in onboard memory by day.  At 0:01 UTC each day it closes the active file and opens a new file for the current day.  The old file (“yesterday” UTC) needs to be transferred off of the Trimble for safekeeping.

Step 1:
Run GPLoad by double left clicking on the desktop icon.

Step 2:
Click on “connect”.

Step 3:
Scroll down the list of available files.  These are the data files stored in the memory of the Trimble data logger.  Find the file with a start date from the previous day (e.g. 8/8/98 00:01).  Note that more than one file may exist for a given day if the power to the GPS was interrupted or the datalogger restarted during the day.  The name to the extreme left is the session name.  The correct session name for the CAMEX-III experiment at Andros Island is  “bago-cmx-3”.

Step 4:
Highlight the available file which you’d like to transfer to the laptop computer.  Press Add.  This adds the file in the “Selected Files” list.

Step 5:
In order to have unique file names on the laptop computer we need to rename the file before transfer.
Highlight the selected file in the “Selected Files” list using a single left click.  Press the “Rename” button and enter the new file name (e.g.  BAGO220 ).  The proper naming convention for the CAMEX-III experiment is as follows:  the four letters BAGO in all capitals followed by the Day of the Year corresponding to the date of the data file.  Please check the calendar AND USE THE CORRECT DAY NUMBER.  If more than one file exists for a given day please add “a”, “b”, “c”, etc. to distinguish the separate files.

Step 6:
Check that the destination directory is c:\gpload\data.  Then press the “Transfer” button.  The program will indicate the progress of the transfer which should take a minute or two.  After the transfer double check that the correct file name is listed in the right hand column of the Available Files list.

Step 7:
Repeat Steps 3 to 6 for each file that has not already been transferred.  Note that transferring the data does not remove the data from the Trimble.  The Trimble will retain all data until additional space is needed at which point it will delete the oldest data files first.

Step 8:
When transfer is complete press “Disconnect” and “Close”.

 II. Compress the GPS data files

What:  Use WinZip to create a “zip” archive of the data files transferred from the Trimble GPS datalogger.
When:  After completeing the steps in I. Above.
Why:  Combines multiple data files into one archive file per day and compresses the data by over 50% which speeds the transmission of the data back to Wisconsin

Step 1:
Run WinZip from the desktop icon.

Step 2:
Click “New” to create a new zip archive file.

Step 3:
The default directory should be c:\gpload\data.  In the file name dialog box type the name of the zip file (e.g.  BAGO220 ) and press OK.

Step 4:
Press the “Add” button and select all the files for the appropriate day (e.g. BAGO220.dat, BAGO220.eph, BAGO220.ion, BAGO220.mes).  Include all files for a given day into this archive (e.g. BAGO220a, BAGO220b, etc.).   Use the Ctrl key and the Shift key to select multiple files then press the Add button.   This will create a file in the directory c:\gpload\data with a “.zip” extension (e.g.

Step 5:
Close WinZip.

III. Upload the GPS data to the Wisconsin Data Archive

What:  ftp transfer of the GPS data to
When: On a daily basis following part II above.
Why:  Dave Tobin needs to convert the raw data files to precipitable water vapor.

Step 1:
Run WS_FTP95 from the desktop icon.  Note you may have to connect to the internet via modem before proceeding.

Step 2:
Select “GPS Upload” from the Profile Name drop down menu list and press OK.
The “Local System” directory should be C:\GPLoad\Data.  The “Remote System” directory should be “/home2/davet/GPS/Data”.

Step 3:
Create a new directory on the “Remote System”.  Press the “MkDir” button on the right hand side of the screen and enter the directory name (e.g. BAGO220, all caps please).

Step 4:
Double click on the “Remote System” directory just created to change the default directory (e.g. /home2/davet/GPS/Data/BAGO220).

Step 5:
Select the zip archive to be transferred under the file list on the “Local System” (e.g.
Press the right arrow button in the center of the panel to begin transfer of the data file (about 770 KB).
Please double check that the file was completely transferred.  Close and Exit WS_FTP.