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could become a protocol of management of all the 
quarries in the Lombardia Region (about one hundred). 
1. The Survey 
The survey is divided in two phases: in the first it has 
been organized and realized a network to move from the 
local system to the Italian Geodetic Datum, in the second 
it has been realized the survey of the detail. 
1.1 The realization of the network to support the 
survey of the different quarries 
The choice to adopt the GPS instrumentation is justified 
by the advantages respect to the traditional methodology 
which consists in the use of the total station to connect 
the vertices materialized inside the quarry surface to the 
vertices belonging to the Italian Geodetic Datum. GPS 
system allows a standardization of the procedures of 
datum, which are independent from the typology of the 
quarry and, in part, from the disposition in the territory of 
the vertices of the reference network. 
The procedures and methodologies here tested in the 
different case-studio can be generalized to the all cases 
of quarry survey. 
It has been defined an approach to carry out an agile 
survey system: this approach can be easy realized and 
verified with the instruments and software of data 
processing today available in sale. 
To guaranty the precision requested in the GPS network 
it must be used a static approach with the analysis of the 
differences of phases of the carrier wave. 
The characteristics of the instrumentation and the 
modality of use are described as follows. 
GPS receiver. 
It must be used the double frequencies, L1/L2, receivers 
with registration of the “C/A” code on the carrier L1. The 
double frequencies receivers allow to minimize the 
influence of the ionospheric component: the course of the 
electromagnetic wave between the satellites and the 
receivers isn’t the same. 
To obtain the contemporary evaluation of three 
independent baselines were implied 4 receivers with 
double frequencies antennas. 
The receivers have to be programmed with a cut-off angle 
of 15 degree and with a sampling rate of 15 sec. 
It is also necessary that at least 4 satellites must to be 
always contemporary viewable with GDOP (Global 
Diluition of Precision) ^ 5. 
The Session of measuring (the time interval in which the 
receiver are contemporary working) depends on the 
distance length of the baseline, and, on the hypothesis of 
5 satellites, the time acquisition is 15 sec. 
Particularly for each receiver 5 difference of phases 
relative to the 5 satellite are measured: from these 
differences of phases are determined the differences 
between the two receivers and the different satellites, and 
trough these are obtained the five double differences; of 
these observations only four can be considered as 
independent. For this reason in one minute 16 
observations must be considered . 
To assure a good local redundancy, in order to allow in 
the adjustment the localisation of the observations 
affected by eventual rough errors, the number of 
baselines which converge to each vertices must be ^3. 
Generally the scheme of the survey will be composed by 
a four side polygon of which are measured 6 baselines to 
each point (the common side between the two four side 
polygon is determined two times). 
To maintain an equal time of observation among the 
different sessions, the polygon was built with an almost 
regular length of baselines. 
The contemporary use of four GPS allows to survey, for 
each session of measure, 3 independent baselines; the 
determination of each polygon is made with 2 sessions of 
measure that requires the repositioning of the antennas 
on the vertices. The high of the antenna must be acquired 
measuring in three different positions the slope distance 
between the vertices and the three position of the ground 
plane. 
Once completed the survey of each four side polygon the 
two queues receivers must move forward while the others 
have to remain fixed. The other vertices of the network 
(and the secondary GPS vertices) can be surveyed 
through independent session of measure and connected 
to each one on the 3 vertices of a four side polygon. 
This schema requires 3 fixed receivers on three vertices 
of the 4 side polygon and a third mobile receiver. On 
these points it is possible to make two session 
consequently, repositioning the GPS antenna as 
explained. 
The vertices of the network must be materialized in the 
way to remain in good conditions in the time. A good 
quality of monographs, containing pictures and the point 
co-ordinates have to be made. 
1.1.1 The survey of the fist order vertices 
The co-ordinate system to which refer the vertices of the 
network is the Gauss-Boaga system (Italian National 
Datum): Cartesian co-ordinate Est-North and for the 
height respect to the medium sea-level. It is possible to 
determine the last one applying the corrections to the 
ellipsoid height coming from the satellite measures with 
the data, locally estimated, of the undulation of the Geoid 
or using the corrections estimated using the benchmark 
of the IGM (Istituto Geografico Militare) network or the 
Verano Brianza