From: Carl Stafford [lacertareptilis@peoplepc.com]
Sent: Tuesday, May 03, 2005 10:04 PM
To: aiken@utdallas.edu
Subject: Exercises

Dr. Aiken,

Code Observations:  

04/25/05

PDOP was good for nearly the entire afternoon, resulting in good conditions for Satellite surveying with the Garmin handheld.  Horizontally, WAAS results were much more consistent than non-WAAS.  WAAS results also seemed to be less affected by Satellite visibility, with the non-WAAS results being forced further away from the actual points being measured when near obstructions.  As for vertical, error was higher for both WAAS and non-WAAS than it was for horizontal measurements.  Non-WAAS was still prone to much higher inconsistencies vertically just as in the horizontal results.    These results seem to be consistent with the Forest service study.

04/26/05

Using the Geoexplorer in the from about 5:30 to about 7:30 on this day was not the best for either PDOP or satellite visibility.  However, problems were minimized by taking few shots near building obstructions.  The Geoexplorer data, when post processed, produced data consistent in quality to that of the forest service study, with control points checking within about 2 meters.  This seems to indicate the quality suggested of the Trimble receivers by the forest service report.

Carrier Methods:

(Page for calculation of Geoid Height for GEOID03) http://www.ngs.noaa.gov/cgi-bin/GEOID_STUFF/geoid03_prompt1.prl 

(Page for finding Bench mark control at a given distance from a designated radius point) http://www.ngs.noaa.gov/cgi-bin/ds_radius.prl

As data time intervals decrease in length, so does the accuracy of the solution produced by CORS.

Carrier Presentation:  

I am currently working on producing a data set for a tract of land in Allen.  This extensive parcel should provide more than adequate information for a suitable report.  I now have about two thirds of the data collected and expect to begin map preparation within the week.

Thank you,
Carl Stafford


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