Activity recognition using array antenna

Nowadays, the population of elderly persons who live alone is increasing in Japan. Some systems are available to monitor those persons' activities, however, they have some limitations; physical burden and need to wear sensors. In our previous work, we have proposed a fall detection method using an array antenna. Array antenna is an antenna, which detects radio wave propagation by observing the direction of arrival (DOA) of the received signal. In the conventional method, it can only detect whether the activity is fall or not, so it is impossible to recognize which kind of non-fall activity the person does. In addition, the detection accuracy of the non-fall activity is not so high, because of the difficulty to detect the difference of fall and sit. In this paper, we propose an activity recognition system by using array antenna. We detect the person's activity (fall, walk, sit, and stand still). To improve the accuracy, we set thresholds for the continuous number of each activity, and correct the result which continues less than the threshold. Also, we use the state transition of the activity, and correct the impossible activity transition.