Patent ID: 8454528

Claim:
A method of sensing motion using a motion sensor, the method comprising: generating electromagnetic radiation from a source of radiation, wherein the frequency of the electromagnetic radiation is in the radio frequency range; transmitting the electromagnetic radiation towards a subject using one or more transmitters; receiving a radiation scattered at least by the subject using one or more receivers; extracting a Doppler shifted signal from the scattered radiation; transforming the Doppler shifted signal to a digitized motion signal, said digitized motion signal comprising one or more frames, wherein the one or more frames comprise time sampled quadrature values of the digitized motion signal; demodulating said one or more frames using a demodulation algorithm executed by a processor to isolate a signal corresponding to a physiological movement of the subject or a part of the subject; analyzing the signal to obtain information corresponding to a non-cardiopulmonary motion or other signal interference; processing the signal to obtain information corresponding to the physiological movement of the subject or a part of the subject, substantially separate from said non-cardiopulmonary motion or other signal interference; and communicating the information to an output system that is configured to perform an output action, wherein demodulating said one or more frames comprises: computing in the processor a first set of covariance matrices of a first subset of frames selected from said one or more frames and a second set of covariance matrices of a second subset of frames selected from said one or more frames; determining a first A-matrix, wherein the first A-matrix comprises a weighted sum of the first set of covariance matrices; determining a first parameter vector corresponding to a first primary value of the first A matrix; storing the first parameter vector in a memory device which is in communication with the processor determining a second A-matrix, wherein the second A-matrix comprises a weighted sum of the second set of covariance matrices; determining a second parameter vector corresponding to a second primary value of the second A-matrix; calculating an inner product of the first parameter vector and the second parameter vector; multiplying the second parameter vector by the sign of the inner product and projecting the values of the second frame on the second parameter vector to obtain the demodulated signal.