Indoor granular presence sensing and control messaging with an ultrasonic circular array sensor

Abstract

Providing automated granular control of lighting, along with user-driven control, results in an energy-efficient smart lighting system design while catering to personal occupant preferences. Two functional ingredients in such a system are: 1) sensing that provides granular information on occupant location and 2) a communication system to transmit control messages from a user. In this paper, we consider an ultrasonic circular array sensor that provides the dual functionality of granular occupant sensing and a communication receiver for user control transmissions. A ceiling-mounted sensor configuration with a colocated ultrasonic transmitter and array receiver is considered. To perform presence sensing, this transmitter sends periodic bursts of sinusoidal pulses that, upon reflection from the environment, are received at the array sensor. The echoes are processed to obtain estimates of range, azimuth, and elevation angles corresponding to possible occupant movements. A Kalman filter based on a near constant velocity model is used for target tracking. The resulting occupant location is used for energy-efficient lighting control. A user may in addition control lamps in its vicinity by sending messages at ultrasonic frequency, which are processed by the receiver array, and used to further adapt requested parameters of the lighting system. The proposed sensing and messaging solution is tested in an indoor office space with an eight-element receiver array sensor prototype.