Sharing and cooperation in geo-information technology

Aziz, T. Lukman

Bibliographic data

Monograph

Persistent identifier:: 856479470

Author:: Aziz, T. Lukman

Title:: Sharing and cooperation in geo-information technology

Sub title:: ISPRS Commission VI Symposium, April 15 - 17, 1999, Bandung, Indonesia

Scope:: 1 Online-Ressource (130 Seiten)

Year of publication:: 1999

Place of publication:: London

Publisher of the original:: RICS Books

Identifier (digital):: 856479470

Illustration:: Illustrationen, Diagramme

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Monograph

Collection:: Earth sciences

Chapter

Title:: WG VI/3: INTERNATIONAL COOPERATION AND TECHNOLOGY TRANSFER

Write comment:: Der Aufsatz "Promotion Of The General Understanding And Improvement Of Public Relations, [...] ist im Original nicht enthalten.

Document type:: Monograph

Structure type:: Chapter

Chapter

Title:: GIS TECHNOLOGY TO SUPPORT SURVEY DATA AND MANAGEMENT OF DIFFERENT QUARRY TYPOLOGIES. Carlo MONTI

Document type:: Monograph

Structure type:: Chapter

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 LI. 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 comiected 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 local cartography of the municipality near the quarry: in this case they have to be propagated using the traditional topographic methodology, that’s to say the geometric levelling or the trigonometric one. To test the results of the Est-North co-ordinates of the vertices of the quarry with the GPS approach, these co-ordinates are

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