Intelligent Transport System (ITS) applications have the requirements of accurate and reliable positioning. When stand-alone GPS positioning is used in urban areas, the position result dramatically degrades, because of signal outage and multipath. This paper proposes that outage and multipath measurement be detected and estimated using only the GPS, and shows urban car test results. The car test results reveal that the proposed navigation system provides more accurate and reliable output than stand-alone GPS positioning without the proposed method.

Keywords: urban vehicle, weak signal, stand-alone positioning, car test