The processing of GPS observations in precise positioning is complex and requires professional surveyors since it must be carried out after each static measurement. In GPS network adjustment, the obtaining of the correct coordinates of the determined point is possible after determining the components of GPS vectors and aligning the networks of these vectors, while PPP requires the availability of precise products for the reference satellites orbits and clock. For that reason, surveyors can take advantage of free online GPS data processing. In this paper, the authors compare the results obtained from different sources of free online GPS data processing (AUSPOS, OPUS, CenterPoint RTX, APPS, MagicGNSS, CSRS-PPP, GAPS, and SCOUT) in terms of their accuracy, availability, and operation. This is then compared with free GPS processing software (gLAB and RTKLIB), and finally with commercial software (TBC Trimble Business Center). The results show that online processing services are more accurate than offline processing software, which indicates the strength of their algorithms and processes. The CSRS-PPP online service had the best results. The difference between the relative solution of AUSPOS and OPUS, and CSRS-PPP is insignificant.

Abstract. Geomatics has been an important tool in archaeology. The combination of Geomatics and archaeology adopters have been considered a perfect match, since archaeology often involves the study of the spatial dimension of human behavior over time, and all archaeology carries a spatial component. Since Iraqi archaeology becomes one of the main victims of destruction by negligence and terror attacks, makes our great heritages forgotten. Hence, it is necessary to build a secure database for all Iraqi archeological sites with their two main types (investigated and uninvestigated) and rely on digital system by creating digital maps for each Governorate with their archeological database system. Results of archaeological studies are rich in spatial information. GIS is adept at processing these large volumes of data especially those that are geographically referenced. It is effective, accurate and a fast tool. The tools made available through GIS help in data collection, its storage and retrieval, its ability for customization and, finally, the display of the data so that it is visually comprehensible by the user. The most important aspect of GIS in archaeology lies, however, not in its use as a pure map-making tool, but in its capability to merge and analyze

In the age of the satellite geodesy, the GNSS is widely used in development of geodetic networks and that give much application, for that reason the study is to estimate deflection of the vertical of a point in Baghdad City in Iraq, the estimated depends on the orthometric height, which computed through the levelling and the ellipsoidal height, which computed from the GPS observations. Due to the lack of survey data and the difficulty of taking terrestrial measurements as a result of the security situation the authors used only 5 points for the national network in Baghdad. The deflection of the vertical component component ξ in the north-south direction calculated as ξ=2.5”±0.001” and the prime vertical component η in the east-west direction calculated as η=5.23” ±1.5”. The results were obtained showing that it can calculate the deflection of the vertical at sufficient accuracy.

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