Estimation of the Number of Persons in a Reverberant Environment Using Bistatic Radar

The theory of room electromagnetics provides a simple characterization of indoor microwave propagation. By considering the indoor environment as a lossy cavity, the exponential decay rate of the power-delay profile is related to the total absorption inside the room. In this paper, we explore the possibility of estimating the number of people inside a below-deck ship compartment using only the decay time constant, also known as reverberation time. First, we verify the reverberating nature of the room. Then, we find the relation between reverberation time and the number of people inside the room. We show that it is possible to estimate the number of people with a good accuracy, depending on the number of antennas used. With a success rate of 88%, the estimation error is only 1 person when 16 spatially averaged antennas are used.