Challenges for high accuracy mobile phone positioning

Various geolocation positioning techniques for wireless systems have been recently devised and implemented using either cellular network-based, mobile-based, or hybrid approaches. However, most prominent positioning methods that have been approved for standadization within 3GPP are uncapable to provide high location accuracy in all type of signal environments, especially indoors. Eventhough, new wireless network elements have been introduced to obtain accurate time-transfer in GSM and UMTS netwoks, challenges remain in estimating unpredictable delays in network singalling layers and in estimating closely-spaced multipath components. A unified framework comparing several techniques for estimating the line-of-sight (LOS) component with hign accuracy in a closely-spaced multipath scenario to improve the positioning accuracy is provided.