System for determining a physical metric such as position

Abstract

A system is disclosed for determining a physical metric such as position. The system comprises a local signal generator () configured to provide a local signal and a receiver () configured to receive a signal having properties corresponding to those in a signal transmitted by a trusted remote source. An inertial measurement unit () is configured to provide a measured or assumed movement of the receiver. A correlator () is configured to provide a correlation signal by correlating the local signal with the received signal. A motion compensation unit () is configured to provide motion compensation of at least one of the local signal, the received signal, and the correlation signal based on the measured or assumed movement. A signal analysis unit () is configured to determine whether the received signal includes a component received in a direction that is different to a line-of-sight direction between the receiver and the trusted remote source, wherein the determination is based on the correlation signal. Finally, a metric determination unit or positioning unit () is configured to determine a physical metric associated with the receiver, such as its position, based on the determination made by the signal analysis unit ().