No abstract

The location requirements for emergency callers outside urban areas can hardly be fulfilled without global navigation satellite systems (GNSS). Consequently, interest in positioning techniques based on use of a GNSS such as GPS or on the cellular network infrastructure itself is growing rapidly in the mobile-telephone community. Moreover, the increasing demand for commercial location-based services (LBS) has driven cellularphone and network manufacturers to focus on positioning solutions which are even more accurate than the regulatory mandates for positioning of emergency callers. One example of these upcoming LBS is our PARAMOUNT project, which aims at improving user-friendly info-mobility services for hikers and mountaineers by combining wireless communications (GMTS), satellite navigation (GNSS) and geographic information systems (GIS), based on a mobile client/server architecture. The availability of mobile phones or PDAs with combined GNSS and cellular network-based wireless communication on a high integration level is one primary demand of such LBS applications. Based on this, we will give some initial answers to the question of whether mobile handset architecture synergies exist for the combination of GNSS with wireless location in CDMA cellular wireless networks. In order to identify synergies, we will outline similarities and differences between wireless communication and satellite navigation. In this respect, we pay particular attention to the so-called RAKE receiver architecture employed in mobile CDMA cellular handsets. Our initial investigations will show that the RAKE receiver architecture, on which mobile CDMA cellular handsets are based, will most likely be the one most suitable for achieving synergies between the two positioning techniques within the same mobile handset architecture. Consequently, several receiver components could be used to handle both types of signals (navigation and communications), resulting in a reduction of manufacturing costs and in a decrease in energy consumption.

Under the leadership of IFEN GmbH, the Galileo Test and Development Environment GATE is being built up in southern Germany by a consortium of several German companies and institutes on behalf of the German Aerospace Center (DLR) with funding by the German Federal Ministry of Education and Research. The performance tests regarding the user positioning performance will cover various test scenarios for static and dynamic cases. The tests will be performed in all available GATE operation modes with GATE signals only and in combination with GPS. Preliminary test during system testing phase showed already impressive positioning performance with dedicated signals and services. The paper gives an overview on the variant test scenarios and setups and illustrates the detailed hardware setup. An introduction in the GATE Backend Receiver Software, which computes the position solution, is presented. It describes the test procedures and shows the test results. Finally an evaluation on the different GATE services with respect to the positioning performance is presented.