Global Positioning System Reference
In-Depth Information
8.2 GIS receivers
As in the previous section, an “average” GIS receiver was considered, and the same
processing methods were adopted. However, it was a priori decided to increase the static
processing length session, splitting the raw data in 10 or 20 minutes long files. This is the
average time that an operator could wait to achieve a sub-decimeter positioning accuracy
using a low-cost receiver.
The Fig. 17 shows the post-processing results of raw data files, obtained using the nearest
reference station.
Fig. 17. Positioning quality of a GIS receiver after the post-processing with the nearest
reference station. CDF of the planimetric (left) and altimetric (right) error using static time
sessions of 10 (top) and 20 (bottom) minutes
A low deterioration both in planimetric and in altimetric accuracy can be observed, when
the master is farther than 30 kms from the rover. This deterioration is not due to the low
quality of raw data, but, instead, because GIS receivers are not able to track the L2
frequency. This frequency, in fact, allows to linearly combine measurements to reduce some
of the biases (e.g. iono-free combination).
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