TECHNOLOGY

The Eiger project focuses on the exploitation of the efficient joint use of Global Navigation Satellite Systems (GNSS) signals and Ultrawideband (UWB) positioning in order to allow permanent and reliable outdoor/indoor localization in order to design a hybrid and propagation environment-independent GNSS/UWB-based standalone Personal Navigation Device (PND) that is able to meet the today's most stringent Location Based Services (LBS) requirements in both outdoor and indoor situations. As the EIGER targeted PND virtually eliminates the problem of the handover when it moves from one environment to another, it becomes perfectly suited to situations where transitioning from indoor to outdoor are frequent and unavoidable. This will open the door to an immediate exploitation by the EIGER consortium SMEs of niche LBS related market segments (outdoor-indoor location aware services) such as LBS in: shopping mole, warehouses, ports, airports…



Since GNSS including the GPS and in the near future Galileo, become widely accessible, localization has found application in many different fields. In areas with good Line Of Sight (LOS) to GNSS satellites, this technique provides a good estimate, within a few meters, of the user's location on the earth. However, indoor localization has always been a more difficult problem for several reasons. Indeed, the GNSS signal is distorted by the existing multipath and the lack of LOS in the indoor environment. More importantly, GNSS typically becomes completely useless inside buildings. However the need for accurate geo-location is not constrained to open environments, both in civil and military applications. This constrains the usefulness of GNSS to open environments, and limits its performance in forests or in dense urban environments as retaining a lock on the GNSS signals becomes more difficult. In the commercial fields for example, the tracking of inventory in warehouses or cargo ships is an emerging need. In military applications the problem of "blue force tracking", i.e. knowing where friendly forces are, is of vital importance, especially in urban scenarios.
The limitations of use of GNSS signals for indoor localization can be overcame by their handover to positioning signals that are fitted to such indoor environment when moving from an outdoor propagation situation to an indoor one. As a first consideration, we can envisage the use of narrowband signals for the indoor localization but as such signals suffer more from multipath fading than UWB signals, their use for indoor localisation remains limited. Indeed, the duration of a narrowband signal is always longer than the delay variance of the channel. Conversely, the duration of a UWB signal is always less than the delay variance of the channel. In the case of the UWB system with a 2 nanosecond pulse duration, the pulse duration is clearly much less than the channel delay variation. Thus, signal components can be readily resolved and UWB signals are robust to multipath fading. This is one of the reasons for which UWB has been selected as an appropriate signal to perform indoor ranging and localization.