A GPS real-time system for instantaneous ambiguity resolution: development and experiences

The system described deals with real-time applications where the symbiosis of hardware and software plays a dominating role. Based on the algorithms developed at the Institute of Physical Geodesy allowing instantaneous ambiguity resolution for rapid-static and kinematic positioning, the paper shows the realization-process of an all-purpose real-time DGPS system. Besides the adaptation of the software to the real-time requirements (ambiguity resolution, multitasking, time-minimization, interrupt control, graphical user interface) the selection and arrangement of the required hardware is shown. Only the commercially available hardware is used like TRIMBLE 4000SSi receivers, radio-data modems and penpad computers. First experiences and results of an extensive test campaign are presented. They show the suitability of the system for conventional surveying as well as for navigational tasks and the integration with other sensors