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ESTABLISHMENT AND EVALUATION ASPECTS OF CYPRUS GPS 
PERMANENT NETWORK FOR MAPPING APPLICATIONS 
S.Spatalas b , E.Stylianidis 3 , C. Pikridas b , P. Patias b 
a Geoimaging Ltd, 6 Georgios Seferis Str., 1075 Nicosia, Cyprus - stratos@geoimaging.com.cy 
b Faculty of Rural & Surveying Engineering, Aristotle University of Thessaloniki, Univ.Box. 434, 54124, 
Greece-(sspatala, cpik, patias)@topo.auth.gr 
Commission VI, WG VI/4 
KEY WORDS: Navigation, GPS/INS, Spatial Infrastructures, Urban, Value-added, System, Mobile Mapping 
ABSTRACT: 
The study describes the design, installation, testing and use of a pilot permanent GPS stations network in Cyprus, for mapping 
purposes. In addition, it evaluates its operation in order to produce the infrastructure mainly for mobile mapping applications but 
also any other type of relevant applications. The Continuously Reference Station Network is designed and established according to 
various quality criteria, which are discussed. Several applications using all the available information in static, kinematic in post 
process and RTK using virtual reference station technique and autonomous navigation mode are carried out. Three main groups of 
applications for mobile mapping are identified and investigated: the first group concerns applications requiring low accuracies (up to 
10m), the second group concerns applications requiring medium accuracies (up to lm), and the final group concerns applications 
requiring high accuracies (up to few cm). A detail report about the experimental results, aspects and conclusions is presented. 
Emphasis is also put on a digital aerial acquisition project, using GPS/INS measurements. Furthermore, in order to test the 
effectiveness of using C/A code-data for low cost DGPS applications in real time, appropriate software using the VRS technique is 
developed. For that reason measurements of three permanent GPS stations are analyzed for a determination of a kinematic chain 
which took place in the broader area of Pafos, Cyprus. The positional accuracy of the path is finally assessed by comparing the 
results with post processed trajectory. The results showed that using the VRS station concept with our developed software named 
“3VRS”, similar accuracies can be achieved in distances of up to 20km from the nearest reference station as for short baselines in the 
single station concept. 
1. INTRODUCTION 
The paper presents the results of a research project which 
targets on the design, establishment and evaluation of the 
operation of a GPS permanent network in Cyprus which was 
named Positioning System Improvement (PSI). 
According to the design specifications, the PSI network consists 
of nine dual frequency GPS receivers which are established at 
the territory of the island which is under the control of the 
Republic of Cyprus and illustrated in Figure 1. The purpose of 
the establishment of each station is to provide single and dual 
frequency data for relative positioning and also to transmit 
DGPS and RTK data for real time users (Weber G., 2001). 
The PSI network may have a wide regional coverage where 
ever cellular phone service is available. As a result the GPS 
measurements could be used in airborne mapping operations 
such as aerial photography, LIDAR, remote sensing, 
bathymetric, boundary and cadastre surveys, topographic 
surveys, emergency and accident response systems, 
construction surveys, tracking asset inventory, utility location 
and recovery, mobile mapping-imaging, pavement inventory, 
precise timing, as well as, deformation studies, atmospheric 
modelling and seismic monitoring. Several case studies using 
phase and code GPS data, especially on kinematic mode, are 
carried out and the evaluation of the results is discussed. 
Figure 1. The designed Cyprus permanent GPS network 
2. NETWORK DESIGN AND INSTALLATION 
Firstly, the optimum operation of the GPS reference station 
network has to be ensured. For this reason, the key factors 
which are taken into account in selecting a site for our 
permanent stations are introduced below (Leica, 2001). 
GPS Sky Visibility 
Electromagnetic interferences