Indoor granular presence sensing with an ultrasonic circular array sensor

Determining occupant presence in an indoor environment with fine spatial granularity is useful in a number of smart building control and analytics applications. We present an ultrasonic circular array sensing solution for granular presence sensing. A ceiling-mounted sensor configuration with a co-located transmitter and array receiver is considered. The 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 proposed array sensing solution is tested in an indoor office space with an 8-element receiver array sensor prototype.