DUAL DIFFERENTIAL DOPPLER MOTION DETECTION

摘要

A motion detector has an RF transceiver configured to transmit a first frequency RF signal and a second frequency RF signal into an area where motion is to be detected. A frequency difference between the first frequency signal and the second frequency signal is small and chosen to cause a calculated range dependent Doppler phase shift between the first frequency and the second frequency. The two resulting Doppler shift signals have a frequency dependent on the movement speed of an object in the area, and a difference in amplitude or signal strength between the Doppler shift signals remains relatively invariant as a function of range for a moving object in the area in comparison with an amplitude or signal strength of the Doppler shift signals. Signal level or signal power of a difference in amplitude between the Doppler shift signals is analyzed for the purpose of movement or range detection.

主权项

1. A motion detector comprising:
a Doppler RF transceiver configured to transmit a first frequency RF signal and a second frequency RF signal into an area where motion is to be detected, a frequency difference between the first frequency signal and the second frequency signal being small and chosen to cause a calculated range dependent Doppler phase shift between the first frequency and the second frequency; and said RF transceiver configured to detect the first frequency RF signal and the second frequency RF signal reflected from the area and to produce at least two Doppler shift signals having a frequency dependent on the movement speed of an object in said area contributing to the first frequency RF signal and the second frequency RF signal reflected from said area; wherein signal level or signal power of a difference in amplitude between the Doppler shift signals is analyzed for the purpose of movement or range detection.