UMTS - Competing Navigation System and Supplemental Communication System to GNSS
O. Balbach · 2000
The requirement in USA of providing an accuracy of 125 m for E-911 calls has driven the positioning function of mobile phones. This requirement can hardly be fulfilled without GPS. Usually, with GSM the position is determined with time difference techniques in base stations. The additional drawback is that the user has no direct access to his position (if at all). The new mobile communication standard UMTS foresees WCDMA as multiple access scheme. Therefore, similar position determination techniques as with satellite navigation systems can be applied and the mobile phone can locate itself. The first-glance conclusion is, that due to less disturbing environmental influences (ionosphere, troposphere) but eventually higher multipath delays similar accuracies can be achieved; at least by far enough to fulfill the E-911-requirement.