GNSS positioning has become popular in the past decade as an efficient method of precise and real-time positioning. It is relatively low cost and ease-of-use. Up to now, several parameters were defined to characterize the performance of real-time positioning: availability, precision, accuracy. This research evaluates the performance of signal linear combinations for real-time positioning, both for static as well as the kinematic positioning. This thesis starts with the investigation of linear combinations (LC) rising from the carrier frequencies of the GPS and Galileo system. Some Linear Combination shows potential benefits in carrier phase integer ambiguity resolution, particularly utilizing the E5 Galileo signal phase carrier. For each system, a set of combinations was studied, analyzed, and then selected during the development of a GPS/Galileo positioning method utilizing the Least-squares Ambiguity Decorrelation Adjustment (LAMBDA). Special signal selection can affect the estimated position and its standard deviation. To further analyze, the results obtained from data processing are compared with respect to baselines and signals. The ambiguity fixing rate is correlated with the baseline length and the method as well as the signals that were used. The analysis of the measurement noise level was first conducted to set a baseline for the real-time GNSS positioning application. According to the test results with real and simulated data, the combined GPS/Galileo approach always performs the best, albeit dominated by GPS. Moreover, a combined Galileo linear combination shows the best insusceptibility in the presence of any errors using simulated and real data. Further efforts were spent for the last step. Tests, analysis and comparison of the algorithms were made in simulated scenarios of the two systems under error conditions of typical multipath, troposphere, and ionosphere. Baselines of a length between 1 km to 70 km using real and simulated data were evaluated, followed by final conclusions and suggestions for future work. As the conclusion, Galileo signals have potencies to provide best performances for static and kinematic positioning, particularly when utilizing the E5 Galileo signal. Since the performance was tested using only a limited amount of real and simulated data, further investigations how to fulfill technical and user requirements are recommended.