Title:
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Optimisation of the design of geodetic networks
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Geodetic networks have been observed for centuries with
the designs based on intuition and empirical formulae.
More recently, computer simulation has been pioneered in
order to test networks prior to any observations being
made. This involves the computation of the covariance
matrix of the parameters from which the designer may
determine whether or not the quality requirements of the
prospective user are met. With the increasing cost of
field operations it is becoming more important to find a
set of observations that will meet the quality
requirement whilst keeping costs to a minimum. Such a
network is called an optimum network.
The success'of the foregoing methods depends on the skill
and experience of the designer. Accordingly,
investigations have been carried out to determine the
suitability of determining the optimal design of level
networks. Four methods which solve the second order
design problem to find the optimal design have been
tested. These involve the Khatri-Rac matrix product to
transform the problem into one which may be solved using
either generalised matrix inverses or linear programming.
In addition a way of automating the established
simulation method of network design by removing
observations using a criteria based on the relative error
between stations, whilst considering the reliability of
the network, is examined.
The identification of the requirements of the user and
their presentation in a form which is convenient for
inclusion in mathematical models is also discussed.
It is concluded that the particular methods of finding
the optimal design via a solution to the second order
design problem, which were investigated, are unsuitable.
The automated simulation technique is, however, found to
be succesful when applied to both small and large level
networks and allows a great deal of flexibility with
respect to different optimal criteria.
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