Program - Evaluations
Course:
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402
403
441
442
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490
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GPS 441
February 7, 2006
Having just completed GPS 441, I
want to thank you once again for making this material available
online.
In GPS 441, you discuss the
reference frameworks, transformations and mathematical models for
LSQ adjustments in the versatile 3D Geodetic Model. I particularly
enjoyed this course, as it explained in detail some concepts which
I've only known previously as mysterious formulas out of textbooks
or reference manuals. The PDF supplemental reading material was
equally informative and enjoyable.
These courses go beyond providing
an "overview" of the topics. While most students will appreciate
the material simply for the sake of understanding what takes place
in our GPS receivers and computer programs, a serious student
could use the material presented to actually develop a core engine
for adjustment software.
William Giel, PLS
Rocco V. D'Andrea, Inc.
Riverside, CT
April 12, 2007
This was my first GPS-GAP course
since the beta release. The new format makes it easier to view
the graphics and to control the flow of the lectures. It is
simple to repeat sections of the lecture to ensure a better
understanding of the material.
I thoroughly enjoyed this
course. The content was well developed and flowed logically. Two
thirds of this course deals with reducing field observations to a
form that can be used in an adjustment employing the 3d geodetic
model. The discussions of spherical trigonometry, polar motion,
gravity and deflection of vertical are necessary to prepare the
student for the final three lectures.
In the final three lectures the
3d geodetic model is presented and developed. The non-linear 3d
geodetic model is introduced and then linearized so that it can be
used in the adjustment algorithms taught in GPS401 through
GPS403. Before taking this course I read about the 3d geodetic
model in several sources. I found the formulation of the
observation equations as functions of local neu coordinates
confusing. The section of lecture eight dealing with
reparameterization from geocentric XYZ to local neu made these
concepts clear. The concepts are all brought together in the
final lecture through the use of Mathcad to perform a 3d
adjustment.
I primarily use two adjustment
programs, Columbus and Geolab. Both these programs use the 3d
geodetic model. I now a have a much better understanding of the
theory and algorithms involved in the adjustment engines for these
two programs.
Peter Lazio, PLS
Patchogue, New York
April 19, 2007
What I found satisfying with this
course was the thorough explanation of the mathematics of the
three dimensional model. Along with the use of the diagrams and
supplemental reading files, the derivation of the 3-d
model was presented in clear and uncomplicated style. I found the
diagram showing the relationship of the Cartesian (XYZ)
coordinates and local (neu) coordinates especially informative and
simple to understand.
Again, all of the MathCAD labs
reinforce the lectures and show how the calculations are related
to each other. MathCAD Lab 7 Model Functions, details the coding
for all of the individual 3-d calculations. There was no need to
reinvent the wheel, just put the codes together to obtain the
results.
The supplemental reading material
on spherical trigonometry, polar motion and deflection of the
vertical were very informative.
The time and effort was well
spent, and I am looking forward to the next course. Thank you for
providing this educational platform.
Wayne M. Teruya, PLS
Honolulu, Hawaii
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