Not only in the car, mobile phone or for banking transactions (exact time), and electricity and telecom providers, but also in rescue services or in the military (keyword infantryman of the future) satellite navigation is used. But not everywhere satellite navigation is possible. There are places where availability or accuracy is limited or low. In particular, Austria is affected by such areas due to its topographical location in the Alps. To mention here are mainly mountain valleys and gorges; but the list is not complete when talking about natural topography. Also urban canyons, narrow streets in cities complicate the reception of the signals of global satellite navigation systems (GNSS) or make them completely impossible, especially if you consider today’s equipment (Single frequency receiver GPS L1 only) of the action forces.

Surely, there's a way to overcome the problem, namely, to use a multi-GNSS receiver. However, this means new investments to a not inconsiderable degree. A precise multi-GNSS receiver with no special option costs of the order of at least 10 k€, plus a corresponding antenna, reference stations for DGNSS and Multi-GNSS software. With 100 users you already have a total of more than 1.5 M€! To what extent the multi-GNSS receivers are really guaranteeing a solution is an open question. Multipath effects and unfavorable geometry of the receiving satellite configuration may hinder it. In addition, the procurement cycles in the military are by far greater (> 15 years) than in the civilian world (around 3 years). Are there other solutions for navigating in narrow valleys or urban canyons when the user has only One-GNSS-receivers which are able to track only one global satellite navigation system (e.g. GPS or Galileo)? This feasibility study is devoted to find answers to this question.

For this purpose, three approaches are investigated: 1. GNSS Re-Radiator / Repeater 2. Local mobile pseudolite systems 3. GNSS reflectometry in valleys

Goal and result of this study should be a recommendation for the technical and cost-effective availability of GPS positioning and navigation in the Alps for the Austrian Armed Forces without the acquisition of new multi-GNSS receivers. This would mean a significant cost saving compared to a new purchase.