Satellite based positioning has existed for over 50 years, but this service wasn’t always as precise as it is today. Regardless, satellite based positioning services are still not perfectly precise. Considering that just about every modern smartphone can provide it’s user with real-time satellite position, this master’s thesis was created to analyse the precision of static and dynamic gps positioning using smartphones. Precision and correction of positions is thoroughly compared between each device in comparison with referent point and track. In current time, most smartphones have the ability to provide satellite based positioning and a significant amount of people use those services as their primary mean of navigation unaware that it might not be correct. Rijeka Bay was chosen to test these services. Considering that GPS is prevalent in amount of satellites in GNSS, only that system will be used in comparisons for smartphones. Using referent point and track, GPS position measurement was created with four smartphones and one multifrequency GNSS receiver. All deviations are shown both graphically, as well as numerically, and their outputs are explained. Measurements were divided to static and dynamic measurements to try and recreate typical real life conditions. Testing grounds for these measurements was Rijeka, Kostrena shore and Bakar Bay due to a favourable contrast between an open and constrained nearby geographical relief. Dynamic measurement was divided into three categories containing stabilized sailing in open areas, manoeuvring in sky constrained areas, and manoeuvring in once again open areas. Large deviations were noted between devices, including very large fluctuations; however, overall coverage with GPS satellites was found to be good and position precision on average was not considerably affected by changing environment. For a better insight in smartphones’ GPS positioning capabilities in Rijeka Bay, further research in varying weather conditions is recommended.