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Geoinformatics-8-2009
article standards inside the geodetic/surveying profession and bussines as well as in the relations with the wide user community of the relevant application fields. it is important to understand, that the adoption of geodata standards is closely connected with the software standards. location-aware technologies (lat), including the gnss and radiolocation methods, backed up by telecommunication systems of mobile networks, enable measurements of the basic entities and their relations in spatial and temporal resolutions, which were almost unimaginable some decades ago. the procedure of geolocation change registration in space requires a synthesis of usage of gnss in combination with other geodetic application technologies. among them are technologies like ins - inertial navigation systems, terrestrial geodesy, aerial and satellite photogrammetry, remote sensing imaging techniques like lidar - light detection and ranging, insar - interferometric synthetic aperture radar. lately, new technologies like wi-fi wireless lan positioning, uwb ultra wide band indoor positioning, rfid radio-frequency identification and other technologies are used in combination with geodetic application technologies. all these and other technologies supply data to a variety of geoinformation management, analysis and presentation systems, using digital and mobile communication techniques, like gsm - global system for mobile communication, gprs - general packet radio service, umts - universal mobile telecommunications system, tcp/ip - transmission control protocol/internet protocol, etc.. a concept of sensor web, measuring dynamic geospatial, spectral, and temporal characteristics using a new intelligent data collection system paradigm, is already evolving, especially in remote sensing applications supported by underlying communications fabric facilitating the exchange of sensor measurement data and results. figure 14. international terrestrial reference frame (itrf) consists of a set of instantaneous coordinates (and velocities) of reference points - mainly space geodetic stations and related markers - distributed on the topographic surface of the earth (credits: iers). edge in the field of geolocating to support scientific, environmental, economical and social activities of humankind. rapid development of electronics, computers and space technologies in the last half of the century provided geodesy new efficient tools with a great impact to the meaning, precision, reliability, amount and renewal cycle of spatial data. global geodetic community seized the opportunity to establish a global terrestrial reference system. to provide quality, precise and reliable use of the rapidly growing amount of global spatial data from various sources, geodesy has to use a dynamic and interdisciplinary approach now to empower it as a basis of precise spatial geoinformation infrastructure. 4 conclusion 3.5 combined geodetic methodology for determination, monitoring and registration of geolocation changes the geodetic methodology is applied. individual fields of geolocation applications are characterized by different levels of change dynamics, which demand from geodesy an adapted quality approach for every field in order to define geolocation as a function of time. geodetic methodology is defined with the necessary quality of individual demands of the application. for example, the range of necessary position precision is 0.1 mm in deformation monitoring of built environment or a few centimetres in registering land property borders to several metres or more in navigation and location based services (lbs). on the other hand, geolocation of objects or states as a function of time changes with different rates in individual relevant application fields. for example, in monitoring geodynamic phenomena the geolocation change rate is measured in mm/year, geolocation change rates in built environments can reach cm/month, while in lbs the geolocation change rate can reach several tens of metres/second. to the entire variety of relevant application fields geodesy has to provide appropriate geodetic space-time framework that is fulfilling the requirements of the standard quality model for spatial data regarding the overall quality elements of purpose, usage and source and quantitative quality elements of completeness, logical consistency, positional accuracy, temporal accuracy and thematic accuracy. in order to succeed in this enormous task, one of the most important issues for geodesy is a widespread adoption of international geolocation and timing are basic information. acquiring, maintaining, servicing and representing spatial data on geolocation as a function of time and with the different levels of quality, is the working field of geodetic science and profession with a vast area and variety of possibilities for modernization and improvement. every scientific effort to increase systematic development in this field is an important contribution to science. it will lead to a more optimal usage of the data, provided by geodetic science, profession and service in all those segments of society, where geolocation and timing information is relevant. with the analysis of geolocation significance as a function of time in describing the real and virtual world, geodesy and the geodetic methods of geolocating have to provide the bases for the the entire range of individual geospatial and timing applica- figure 15. the wgs 84 coordinate system definition (credits: nima). 40 december 2009
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