Location of third generation mobile devices: a comparison between terrestrial and satellite positioning systems

The mobile communication world is increasingly concentrating on the development of new functionality for third generation (3G) mobile devices. Locationing is considered one of the key features to enable a high number of interactive services and has been addressed within the 3GPP standardisation groups. This paper presents an analysis of the two techniques aimed to provide accurate location of mobile devices within IMT2000-DS (UTRA FDD) mode: the observed time difference of arrival (OTDOA) and the assisted global positioning system (AGPS). An overview of the technology is given along with results of OTDOA simulations and trials with experimental GPS hardware. Many factors influencing the choice for a positioning system are discussed: from accuracy to impact on the handset and the network, cost and ease of integration.