Real-time precise GPS for railroad mapping

Real-time GPS, now available to centimeter accuracy, provides a tool to rapidly collect co-ordinate information. The ability to obtain these co-ordinates in real-time creates many more possible applications. One such application of real-time precise GPS analysed here is mapping railroads. This paper describes an application where GPS equipment was mounted on a survey vehicle to enable centimetre accurate 3D co-ordinates to be collected in real-time to map railroads. The Leica System 300 with RT-SKI was deemed as a suitable system to fulfil the requirements of such an application. Each of the components of the system are analysed and the results from a survey are presented. The results shown highlight the suitability of real-time precise GPS to provide the required accuracy, and it is also shown that the GPS method is far more cost effective than traditional surveying techniques.