Achievable Positioning Accuracies in a Network of GNSS Reference Stations - Global Navigation Satellite Systems: Signal,Theory and Applications - page 204

7.1.3 FKP positioning
The FKP positioning, as seen in previous sections, consists of broadcasting to the rover the
bias flat model parameters estimated by the GNSS network software. The hypothesis that
spatial delay variations can be arranged along a plane is certainly reliable for small
networks, but become trivial when the inter-station distances become too high. In that case,
in fact, local atmospheric phenomena, which can cause considerable disturbances in the
GNSS observations, are not taken into account. The positioning results obtained by the use
of a geodetic receiver corrected by a FKP model are shown in the Fig. 10.
Fig. 10. Positioning quality of a geodetic receiver when a FKP correction is used: CDF of the
planimetric error (top left) and of the elevation error (top right), cumulative moving average
of the planimetric error (bottom left) and of the three-dimensional positioning error (bottom
right)
As it is possible to see in the previous figures, a flat interpolation model allows to achieve a
positioning error equal to or slightly greater than 10 cms (95% of reliability) only when small
networks (e.g. the “red” one) are used. When medium-sized and large-sized networks (the
“green” and “blue” ones, respectively) are used, the planimetric average error exceeds 20
cms. A very similar trend is found also for the elevation error, which increases from 15 cms
(“red” network) to over 30 cms (“green” and “blue” networks). There are, in this case, no
significant differences between the two wider networks.