Implementation of a nationwide wide-area multilateration system for Austrian Airspace

Primary challenges are site selection and installation as well as optimization; Well-defined scoring system for siting is an aid and allows use of automated siting algorithms to select from a large number of potential sites; Visiting of potential sites and feed back of any line-of-sight or power issues into siting is critical; Optimization requires clear definition of the coverage and the performance of the system; Preliminary results suggests that all performance requirements are met, with a larger coverage volume than required; According our current cost-benefit analysis, a reduction of the surveillance life-cycle costs will be reached.