Degraded GPS Signal Measurements With A Stand-Alone High Sensitivity Receiver

Abstract

The use of GPS for personal location using cellular telephones or other devices requires signal measurements under both outdoor and indoor situations. The outdoor environment may range from clear to shaded/blocked signal measurements. The indoor environment may range for single floor wooden constructions to high-rise buildings and underground facilities. In this paper, a high sensitivity receiver that operates in unaided stand-alone mode is tested under a range of shaded signal environments, ranging from residential outdoor areas to urban canyons to residential houses. The measurement analysis is performed in both the observation and position domains. The results show that the receiver tested can yield measurements with C/N0 degradations in excess of 20dB-Hz, as compared to lineof-sight measurements. Position results are a function of the geometry of the remaining satellites, which in turn is a function of the environment.