Since the advent of Geographic Information Systems (GIS) people specialised in this area or connected with GIS at an administrative or user level have been looking for economical and productive means to accomplish data acquisition tasks. Because the data acquisition constitutes a major part of any GIS, the scientific community, especially geodetic surveyors, have come up with the real time kinematic (RTK) GPS solution. This paper investigates the performance (internal and external accuracy) of RTK GPS. For this purpose, two separate tests are conducted. In the first test, three cases are taken in consideration for internal accuracy, namely, identical satellite configuration, different satellite configuration and different reference station. In the second test, two cases are examined in which RTK GPS results are compared with the static GPS and conventional terrestrial methods. The results from all the tests have proved that this modern technique is very suitable for data acquisition of GISs as well as efficient and economical.