Global Positioning System Reference
In-Depth Information
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residuals). The outliers seen for small residuals refer to the group of observations
with smallest redundancy numbers.
Figure 8.15 shows absorption versus redundancy. Absorption specifies that part of
a blunder which is absorbed in the solution, i.e., absorption indicates falsification of
the solution. The values
A
k
=−
v
k
+
B
k
(8.34)
are plotted. As expected, the observations with lowest redundancy tend to absorb the
most. In the extreme case, the absorption is infinite for zero redundancy, and zero for
a redundancy of 3 (vector observations). Clearly, very small redundancies reflect an
insensitivity to blunders, which is not desirable.
As is the case for terrestrial observation, it is not sufficient to limit quality control
to residuals and normalized residuals. It is equally important that the quality of
the network be presented in terms of redundancy and reliability measures. These
functions are, among other things, useful in judging the implications of deweighting.
The consequences of deweighting are not always readily apparent in large networks.
[La
[32
Lin
—
3
——
Nor
PgE
[32