LocataNet: Intelligent time-synchronised pseudolite transceivers for cm-level stand-alone positioning

The use of GPS for indoor positioning poses difficult challenges due to very weak signal levels, and accuracies are typically of the order of tens to hundreds of metres at best. To overcome this severe limitation, Locata Corporation has invented a new positioning technology called Locata, for precision positioning both indoors and outside. Part of the “Locata technology” consists of a time-synchronised pseudolite transceiver called a LocataLite. A network of LocataLites forms a LocataNet, which transmits GPS-like signals that allow single-point positioning using carrier-phase measurements for a mobile device (a Locata). The SNAP group at UNSW has assisted in the development of a Locata and testing of the new technology. In this paper, the prototype “Locata technology” is described, and the results of indoor positioning performance test experiments are presented. Test experiments demonstrate proof-of-concept for the “Locata technology” and show that carrier-phase point positioning (without radio modem data-links) is possible with sub-centimetre precision.