FLOOD10356

• Designation Number: 596
• County: Adams
• Stream Name: Comanche Creek, Wolf Creek
• Basin: South Platte
• Title: Floodplain Study - Comanche Creek and Wolf Creek - Technical Appendix
• Date: 5/1/2002
• Prepared By: McLaughlin Water Engineers, Ltd.
• Floodplain - Doc Type: Floodplain Report/Masterplan

sometimes occurring, but problems failed to occur and rapid static procedures
proved to work very well. Data processing was performed by GeoGenius,
v2.0 and PNAV, v2.502. All baselines processed passed software checks,
and only double-differenced, fixed solutions vectors were output; adjustments
accomplished through Fillnet, v3.00.

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reports are In appendix

The free adjustment of all vectors has a standard error of 0.856, showing
internal consistency of the GPS results, h.i. observations and occupation
errors at approximately the part-per-million level. The standard error is
reasonably close to 1.0, reflecting the part per million accuracy of rapid static
GPS processing. Residuals in all components are generally at the sub-
centimeter level, and positional accuracies also average approximately 1 cm
(10). Errors are propagated in Fillnet according to default apriori values of
3mm + 1 ppm in latitude, 5mm + 1 pP}l1 in longitude and height, and at 1 ppm *
baseline length. The covariance matrix derived from the post processing
statistics was not used as a weighting strategy in this adjustment.

Processing

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The preliminary final adjustment has a standard error of 1.593; the slight
increase in the s.e. is due to the constraint of existing NGS control. Five
perimeter horizontal control points were equally weighted for the final
adjustment. The weighting strategy for the final horizontal adjustment was
changed from a 1 ppm error propagation multiplier to a 1.5 ppm multiplier to
bring the s.e. to 1.135. The average horizontal residual was 0.009m and the
average vertical residual is 0.013m. At 10, the horizontal accuracies are in
the 1 cm range, and the vertical accuracies are in the 2 cm range, except for
PP08 (0.030m).

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Adjustment reports are in appendix

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