K20s
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and consistency. General speaking, the amount of baselines has such limit as follows:
The advantage of circle net is the small workload, good self-checking and consistency. But the
main disadvantage is that the accuracy of indirect-observed border is lower than that of
direct-observed border, and the baseline accuracy of neighbor points distributes unevenly. In
field surveying, we usually use annexed traverse as special example according to practical
situation and the net usage. This requirement for this traverse is the high accuracy for the known
vectors between two point ends. Furthermore, the amount of annexed traverses cannot exceed
the limits.
Star shape net
Star net has simple geometry graph, but the baselines of it mostly don‟t compose a closed graph,
so it has a bad checking ability and consistency.
The advantage of this net is that it only needs two receivers, the work is very simple, so it is
mostly used in the quick surveying as quick static orientation and kinematical orientation. This
working mode is widely used in project layout, border surveying and GIS surveying, etc.
§6.1.5 Antenna Height Measurement
After fixed the instrument, user should measure antenna height at the beginning and the end of
every period of time to ensure the accuracy “mm” level. We usually measure from the center
point on the ground to the center waterproof loop of antenna. That is an inclined height. Please
refer to the following figure.
