Laser scanner has become widely used nowadays for several applications in civil engineering. An advantage of laser scanner as compared to other geodetic instruments is its capability of collecting hundreds or even thousands of point per second. Terrestrial laser scanner allows acquiring easy and fast complex geometric data from building, machines, objects, etc. Several experimental and field tests are required to investigate the quality and accuracy of scanner points cloud and the 3D geometric models derived from laser scanner. So this paper investigates the precision of creation three dimensional structural model resulted from terrestrial laser scanner observations. The paper also presented the ability to create 3D model by structural faces depending on the plane equation for each face resulted from coordinates of several observed points cover this face using reflector less total station observations. Precision comparison for the quality of 3D models created from laser scanner observations and structure faces is also presented.The results of the practical measurements, calculations and analysis of results are presented.

The modernization of GNSS provides promising improvements to satellite navigation users across the world, it is important to determine the reliability of using free online processing software for the Global Navigation Satellite System post-processing. The study aims at assessing the accuracy of two free online processing software, GAPS, and CSRS-PPP and Open-source software, PPPH MATLAB based software, and GNSS solutions. Field observations were carried out on data from three stations using GNSS observation from IGS with an observation period of 30 seconds the acquired data were post-processed using both online and opensource software. The coordinates generated from each software were then compared with the ones obtained from station to determine their relative discrepancies and accuracies. for GAPS and CSRS-PPP both in X, Y, and Z direction in ITRF14 reference. Online GNSS processing services are easy to use, do not require the knowledge of GNSS data processing and can be adopted for engineering and geodetic applications. Initial time must be checked for better resolution.

One of the primary geodetic mapping tasks in the post-processing of GNSS data is precise point positioning (PPP). Research institutions and universities have established software packages and online PPP services in prior years. Still, it is problematic to satisfy the high-rate update criterion of PPP due to the quick growth of GNSS constellations. In PPP GNSS data processing, Square Root Information Filter SRIF is not frequently handled. In this research, we used the MANS-PPP software package to execute the processing method and generate the PPP GNSS solution. The new program has been demonstrated how can effectively enhance initial time and positioning error for multi-GNSS satellites. Processing observation data with the Kalman filter and SRIF was performed using PPP in static mode for the 16 stations, and the influence of errors has been analyzed from the filtering method. The Kalman filter was unable to maintain a stable convergence curve during the PPP filtering procedure, but SRIF was successful in doing so. Based on these findings, SRIF had better numerical stability and was well-suited for settings with PPP demanding precision computing environments.

Ambiguity resolution (AR) is essential for quick and accurate Global Navigation Satellite System GNSS location and navigation. In addition to location parameters, there are various additional GNSS characteristics that are relevant for a wide range of applications such as instrumental calibrations, atmospheric sounding, and time transfer. We offer differential code bias and satellite geometry for the GNSS estimable parameters using MANS-PPP software backage. In this research, we used the MANS-PPP software package to execute the processing method and generate the PPP GNSS solution. We demonstrated how differential code bias and satellite geometry can effectively enhance initial time and positioning error for multi-GNSS satellites. PPP Processing observation data in static mode was used by the different DCB files the Chinese Academy of Sciences (CAS), the German Aerospace Centre (DLR), and the Centre for Orbit Determination in Europe (CODE), for the 12 stations from IGS, and we analyzed the impact of errors from the satellite geometry. The results illustration that the correction of DCB significantly improves the PPP ambiguity resolution success rate and quality, which have higher DCB values. The satellite geometry also has a substantial influence on the PPP ambiguity resolution, with a better geometry leading to a higher success rate and quality. Furthermore, the use of multiple GNSS constellations and the optimization of the satellite selection and weighting algorithms can further improve the PPP ambiguity resolution and the resulting positioning accuracy.

In order to properly post-process data from the Global Navigation Satellite System, it is crucial to evaluate the dependability by means of online free processing tools because the development of GNSS offers satellite navigation consumers around the globe promising benefits. The purpose of the study is to assess the precision of several online processing tools, including GSIPOST, AUSPOS, IBGE, Magic GNSS, CSRS-PPP, and open-source software. Three stations' worth of RINEX 2 data were subjected to field observations utilising GNSS observations from IGS, with an observation time of 30 seconds. After that, both online and open-source software was used to analyze the collected data, using GPS and GPS and GLONASS. The relative differences and accuracy of the coordinates generated by each software were then assessed by comparison with those acquired from reference stations. coordinates in the ITRF14 standard for the X, Y, and Z directions. Online GNSS processing services don't require GNSS data processing skills and are easy to use, and provide more accurate results for engineering and geodetic uses. RINEX 3 data must be checked for better resolution.