The problem  of locating  objects and  people in  indoor environments  is lately
gaining high interest in research and industry. In this context, the geometrical
constellation  of  source  and  sensors  plays  an  important  role  and heavily
influences the  accuracy for  the position  estimate. This  paper uses  existing
optimal solutions  of the  problem of  three-dimensional TDOA  localization, and
relates them  to practical  application. The  extension is  necessary, since the
optimal solution is only  valid for one single  position and not for  a complete
area, where  a localization  capability is  desired. Therefore,  it is  shown by
simulations that the optimum is very useful for localization purposes in typical
indoor scenarios. Further  it is proven,  that the simulations  can be confirmed
with real-world measurements using an Ultra-Wideband (UWB) localization  system.
Finally, it can  be demonstrated, that  the optimal solution  can be adapted  to
typical  indoor   environments  and   still  yield   accurate  three-dimensional
positioning.