Patent ID: 6856281
Filing Date: 2005-02-15
Classification: G01S

Abstract:
1. A method for obtaining a distance to a target by use of a sensing system comprising a signal source, an antenna, and at least a pair of detectors, comprising the steps of: (a) transmitting a plurality of transmit signals for transmission via the antenna and a plurality of corresponding reference signals for distribution to the at least pair of detectors in response to sweeping in selected frequency increments a frequency band of the signal source; (b) receiving a plurality of received signals via the antenna, each received signal representing a reflection of one of the transmit signals off of the target; (c) identifying a rate of change of phase between the reference signals and the received signals as detected by the at least pair of detectors; and (d) calculating the distance to the target based on the rate of change of phase as a function of frequency between the reference signals; wherein a propagation medium connects the signal source to the antenna, the frequency band comprises the stopband of the antenna, the target comprises the antenna, and the distance to the target comprises the length of the propagation medium and the received signals.