Dai Sasakawa

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.

Cooperative MIMO radar using multiple receiving stations for human localization

This paper proposes a cooperative Multiple-Input Multiple-Output (MIMO) radar for human localization and clarifies the improvement effect of human localization accuracy by the experiment in an indoor environment. In this method, the MUltiple Signal Classification (MUSIC) spectrums observed at all stations are multiplied to enjoy the accuracy and range enhancement due to the multiple stations. The 50-percentile distance error of experimental results show that the human localization accuracy was 0.22 m with use of the phantom and 0.32 m with use of human subjects when the number of stations of the antenna was 4 stations.

Evaluation of fast human localization and tracking using MIMO radar in multi-path environment

This paper demonstrates the measurement results showing the effectiveness of a fast human localization and tracking method suitable for multi-path environment. In this method, a time-differential channel is calculated by taking difference among the observed channels corresponding to biological activity. The human locations are estimated by two-dimensional MUSIC (MUltiple SIgnal Classification) correlation matrix calculated from the time-differential channels. The experiments were carried out in an indoor environment, and the results show that the target locations and trajectories can be estimated by the temporal-subtracting technique. The averaged tracking error is 0.29 m in this experiment.

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.