Differentiate between "biases" and "errors". Comment
on the various classes of biases & errors, and what can be done to account
for them in a Least Squares solution.
Discuss the satellite dependent biases in GPS. What options are available
in accounting for them in data processing schemes?
Discuss the receiver dependent biases in GPS. What options are available
in accounting for them in data processing schemes?
Discuss the ionospheric delay bias in GPS. What options are available
in accounting for it in data processing schemes?
Discuss the tropospheric delay bias in GPS. What options are available
in accounting for it in data processing schemes? Why is it no longer recommended
that met observations be made?
Discuss the common error sources in GPS measurements. What can be
done to minimise their impact?
Derive the basic one-way carrier phase observation model. Include
all the biases typically found in GPS measurements.
Which biases can be eliminated? Which biases can be significantly
reduced? What is their residual effect on baseline determination?
Compare and contrast the one-way (or undifferenced) observation equations
for phase and pseudo-range. Comment on the possible magnitudes of the various
terms in the observation equations.
Comment on the Double-Difference Observation Equation. What do the
various terms mean? Where do they come from? What is known and unknown?
What are the basic assumptions (e.g. about the atmospheric biases, etc.)?
Why do observations have to be made "simultaneously"? How
close is "simultaneous"? How is simultaneity assured in modern
GPS surveying practice?
How are L1 and L2 phase observations combined to give an "ionosphere-free"
observable? What are the disadvantages in using the "ionosphere-free"
observable?
What is a "wide-lane" phase observable? How is it computed?
What are some of its positive and negative characteristics?
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