ORIGINAL PAPER Assessment of NRCAN PPP online service in determination of crustal velocity: case study Northern Egypt GNSS Network Nadia AbouAly 1 & Mahmoud Elhussien 2 & Mostafa Rabah 3 & Zaki Zidan 2 Received: 15 February 2020 /Accepted: 13 January 2021 # Saudi Society for Geosciences 2021 Abstract Precise point positioning (PPP) has the ability to give precise positioning with high accuracy. That may be an alternative to precise Deferential GNSS (DGNSS), in addition to being a low-cost alternative among all processing strategies of Global Navigation Satellite System (GNSS), especially when online services are used. To see the assessment study of PPP in the determination of crustal velocity, 66 days of GNSS data distributed in the period 2013–2015 were used. Composing a network of eight stations called the Northern Egyptian Permanent GNSS Network (N-EPGN) with nine IGS stations was processed. Scientific software GAMIT/GLOBK and Bernese used to calculate the final precise coordinate and the associated velocity of each station in the International Terrestrial Reference Frame (ITRF 2008). Each campaign consists of 3 days. These data were processed by PPP approach. The final precise coordinate and the associated velocity of each EPGN station estimated. The final results compare to those different methods of analysis and programs refer to high level of agreement between the coordinates and velocity which confirm that PPP approach can be applied for the investigation of crustal deformation. Keywords Scientific software . Precise point positioning . GNSS Introduction The crustal velocities play an important role in understanding the crustal deformities of any region, in addition to the asso- ciated causes such as tectonic activities, volcanos activities, landslide, and the underground mining (e.g., gas and ground water) and also their consequences in infrastructure, econom- ic, social activities and change of the existing environment. To determine the crustal velocity values of any station, that re- quires a large amount of continuous or discontinued observa- tions at large intervals of time. It can be done by using con- ventional survey (e.g., precise leveling, tiltmeter) or advanced space techniques such as GNSS. With the development of satellite surveying methods, their availability and high degree of accuracy were modified. Each country began to establish its national geodetic control network and assigned it to an ITRF for using as a three-dimensional geocentric reference system for the country and monitoring all crustal deformation that may occur in the territory. To achieve this goal, normally scientific GNSS profession- al software, like GAMIT, Bernese, and GIPSY, is utilized. The handling of one of these scientific software is subjected to high cost and the need of a very special professionalism. Finally, PPP is known as the most cost-effective alternative to differential GNSS. So, PPP was used to estimate the crustal velocity to clarify the full picture of crustal deformities that occur. Eight stations (Seven from EPGN and AlEX) were processed by Bernese software Ver.5.2 and GAMIT Ver. 10.61 for 66 days of discontinuous data with nine IGS sur- rounding stations. Each campaign consists of 3 or more days data processed by PPP of CSRSPPP software. The current research is emphasized on the possibility of obtaining the sta- tion coordinates and velocity by PPP approach with accuracy suitable for crustal deformation where several millimeter ac- curacies are applicable. For further reading about PPP, there Responsible Editor: Longjun Dong * Nadia AbouAly dr.nadia_aboaly_2010@yahoo.com 1 National Research Institute of Astronomy and Geophysics, El-Marsed Street, Helwan, Cairo, Egypt 2 Public Works Department, Faculty of Engineering, Mansoura University, Mansoura, Egypt 3 Civil Engineering Department, Faculty of Engineering, Benha University, Benha, Egypt Arabian Journal of Geosciences (2021) 14:188 https://doi.org/10.1007/s12517-021-06530-8