Door zone protection

摘要

An apparatus for detecting an object 20 in an area adjacent a doorway includes a plurality of transducers US1, US2 mounted proximate the doorway and a processor 40. At least one of the transducers US1 is positioned to repeatedly transmit signals T1 toward an area adjacent the doorway. At least two of the transducers US1, US2 are positioned to repeatedly receive R1, R2 return signals. The processor 40 is operably connected to the plurality of transducers for detecting, in the area adjacent the doorway, an object 20 by determining the object's: position based upon one or more determined distances d1, d2 derived from times between transmission of signals and reception of corresponding return signals; and/or movement based upon transmission of signals and Doppler shift in the reception of corresponding return signals.

主权项

1. Apparatus for detecting an object in an area adjacent a doorway, the apparatus comprising:
a plurality of transducers mounted proximate the doorway, wherein at least two of the transducers are positioned to repeatedly transmit signals toward an area adjacent the doorway, and wherein at least two of the transducers are positioned to repeatedly receive return signals from a transmitting transducer; and a processor operably connected to the plurality of transducers for detecting, in the area adjacent the doorway, an object by determining the object's position and the object's movement, wherein the processor is configured to measure times of flight between transmission of signals and reception of corresponding return signals and to calculate a corresponding determined distance from the corresponding transducer to the object based on a corresponding time of flight and to derive a corresponding spherical surface with a location of a corresponding transceiver as a center of the spherical surface and the corresponding determined distance as a radius of the spherical surface and to determine the object's position by determining coordinates of an intersection of at least two corresponding spherical surfaces; wherein the processor is configured to determine the object's movement based upon transmission of signals and Doppler shift in the reception of corresponding return signals.