Keita Konno

Experimental Evaluation of Estimating Living-Body Direction Using Array Antenna for Multipath Environment

In this letter, we introduce a method that uses the radar system to observe the waves reflected from the target with the single-input-multiple-output (SIMO) array configuration to estimate living-body directions in a multipath environment for applications such as elderly monitoring. Directions of living body are estimated by the MUltiple SIgnal Classification (MUSIC) method, where the Fourier transformed channel matrix is used. Our use of the 2.4-GHz band allows greater miniaturization of the antenna than is possible with the low-frequency band used by conventional systems. Also, this method can be used in multipath-rich environments such as indoors. The experiments are carried out in a specific indoor environment as a demonstration, and the SIMO channel is measured with various subject numbers and positions. The results indicate that the proposed method can estimate living-body directions with high accuracy even in multipath environments.

Fast estimation algorithm for living body radar

The authors have proposed a direction estimation method of the living-body using array antenna in multi-path environment. However, this method has a problem that takes time as several tens of seconds. In this paper, we present a fast algorithm for estimating living-body direction. The experiment showed that the proposed method works well in estimating living-body direction with high accuracy in multi-path environment even when the observation time is less than conventional method.

Antenna Array Calibration for Living-Body Radar

This letter introduces an antenna array calibration method that uses the channel response with known subject direction so as to accurately estimate living-body directions in multipath environments for elderly monitoring. Said calibration is extracted from the known living-body direction information using the Fourier transformed channel matrix. An experiment shows that the proposed method offers successful antenna array calibration even in indoor environments. Living-body directions are successfully estimated within acceptable error proving that the proposed method is effective in calibrating living-body radars.

Detection performance evaluation of MIMO sensor for outdoor surveillance application

We investigated the antenna arrangement suitable for outdoor MIMO (Multiple-Input Multiple-Output) sensor which is used for intruder surveillance application. Detection rate characteristics are evaluated as functions of the height of antenna array in several environments. A channel correlation that compares the MIMO channels with and without a person is used in the intrusion detection algorithm. The experimental results indicated the intruder detection performance is improved by lowering the height of antenna than the height of targets in outdoor environment.