Patent ID: 8159344
Filing Date: 2012-04-17
Classification: G01S

Abstract:
1. A method of detecting a target within a predefined protected region with a microwave motion detector, comprising the steps of: transmitting microwave frequency signals; receiving the microwave frequency signals reflected by a target; determining, from the received microwave frequency signals, a target distance; determining, from the received microwave frequency signals, a target angle; determining, from the target distance and the target angle, a target location; and setting an alarm condition if the target location is within the predefined protected region; wherein: the step of transmitting microwave frequency signals comprises transmitting a plurality of microwave frequency signals at different frequencies; and wherein the step of determining, from the received microwave frequency signals, a target distance comprises: generating from the received microwave signals intermediate frequency signal components, wherein each intermediate frequency signal component is representative of one of the received reflected microwave signals, sampling the intermediate frequency signal components, determining phase angles from the sampled intermediate frequency signal components, determining a phase difference between the phase angles, determining, from the phase difference, a corresponding target distance measurement.