Isamu Matsunami

Non-invasive respiration monitoring sensor using UWB-IR

Ultra-wideband impulse-radio (UWB-IR) has lately attracted considerable attention as remote medical sensor, since the effective range is in the order of a few meters and it is not affected by clothes or blankets as well. It is therefore expected to detect the respiratory movement of human body such as patient, which is unique as compared with conventional sensors. It is also friendly to the environment including the human body due to the very low electromagnetic energy emission. However, high speed A/D device should be required to detect the small respiratory displacement using a ranging based approach. This paper suggests a remote respiration sensing scheme using the UWB-IR. It also makes possible to design the simultaneous sensing of multiple persons in hospital beds, for example. In this paper the measurements were conducted for various scenarios and the feasibility is discussed.

Human Body Detection using UWB-IR Indoor Channel

Delay profile of an indoor ultra-wideband impulse-radio (UWB-IR) channel should change for the movement of a human body. This paper suggests a human body sensor using the UWB-IR in order to protect a house, not a room, because the radio with high range resolution can penetrate into the walls and the reflected paths from human body and the like should be able to be discriminated in time domain. The usefulness is experimentally investigated under a scenario which a human intrudes into a typical house with four rooms and walks around. It is found from the results that the intruder should be recognized everywhere he stands in the house.

Performance Evaluation of Vehicular Ultra-Wideband Radio Channels

Ultra-wideband impulse-radio (UWB-IR) channel with omni-directional antenna was experimentally investigated inside a vehicle body with passengers where the interference power out-radiated from the vehicle is also discussed. From the result, the RMS delay spread and average delay, which are considerably degraded as compared with the use of directional antenna, are likely to decrease in proportion with the number of passengers in either channel of line-of-sight (LOS) and non-LOS. Also remarkable difference was not seen for the channel bandwidth. And the interference power is found to depend on the antenna height as well as antenna directivity. For example, the attenuations at 3 m away are approximately 80 dB and 60 dB for the antenna height of 0.8 m (below the window) and 1 m (above the window) respectively.

Rake Reception of UWB-IR Indoor Radio with Reflector

Ultra-wideband impulse-radio systems have the ability to resolve multiple paths of the transmit radio and to mitigate the fading. Rake reception is capable of combining these paths, thereby improving the signal-to-noise ratio. In LOS channel, however, the improvement may be comparatively small for the cost of increasing receiver system complexity. This is because the LOS path should be dominant for the total energy in all paths. In this paper the distribution of the energy captured by Rake receiver is first presented for 160 measured LOS channel cases and then discussed. Rake reception with reflector is next suggested in order to effectively increase the signal energy without increasing the complexity, that is, increased number of Rake fingers. The use of reflector is also suggested for non-LOS channel and experimentally discussed where the Rake gain is compared with conventional Rake without reflector. The measurement results show the usefulness.

RCS measurements for vehicles and pedestrian at 26 and 79GHz

The RCS of a radar target is an important factor related with the radar performance such as the detection, tracking and classification. When dealing with the design of radar system for 26/79GHz short/middle-range radars allocated for next generation perimeter surveillance radars, it is essential to know individual RCS of typical vehicles and pedestrian. However, there are few or no reports related to the RCS measurement at the band of 26GHz and 79GHz. In this paper, the RCS measurement of vehicles and pedestrian was performed in a large-scale anechoic chamber and the measured RCS characteristics are discussed comparing the 26GHz and 79GHz band.

Clutter suppression scheme for vehicle radar

Vehicle radar receives echoes from the natural environment such as road and building. These echoes are called clutter which can be much higher than vehicle echo. It is therefore expect to improve the detection performance by summing all the radar echoes available from the vehicle. However, heavy road clutter should not be suppressed less than the vehicle echo by conventional integration schemes such as pulse integration and CFAR (Constant False Alarm Rate). Also the radar echo should include multiple vehicle targets as well as the clutter. Therefore it is not easy to detect multiple vehicle targets from heavy road clutter. In this paper, multiple targets detection with new clutter suppression scheme is discussed and the usefulness is investigated by conducting the measurement. As a result, the suggested scheme is found to suppress the heavy clutter significantly.

Wireless motion sensor using ultra-wideband impulse-radio

Ultra-wideband impulse-radio (UWB-IR) has lately attracted considerable attention because of high range-resolution, penetration against blanket and clothes, low power spectral emission and so on. In medical care or geriatric health care facilities, therefore it is expected to detect the small movement of a resident such as breathing with a remote non-contact approach which is unique as compared with conventional sensors such as infra-red and narrow-band radio. This paper suggests a wireless motion sensor using UWB-IR, which detects various movements of a resident vacating a bedside, room or designated area. It can also monitor the residents respiration rate in bed. In this paper the measurement was conducted for several scenarios and the usefulness is investigated. As a result, it is found to be useful for ant-wandering and respiratory monitoring.

Empirical Study on Ultra-Wideband Vehicle Radar

High range-resolution radar using ultra wideband radio attracts considerable attention as a short range automotive radar. Radar echo from a target often contains unwanted echoes called as clutter, which make it difficult to detect the target. In order to suppress the clutter, therefore, it is important to investigate the clutter distribution and to develop the clutter model. In this paper, traffic road clutter is measured and characterized for various bandwidths from 10 MHz to 5 GHz. It is also quantitatively compared with the model of log-normal, Weibull and log-Weibull.

Power Delay Profile Matching for Vehicle Target Recognition

Radar echo contains unwanted echoes called as clutter, which make it difficult to detect vehicle or obstacle. Especially short-range/wide-angle vehicle radar at 24GHz suffers from heavy clutter unlike long-range radar at 77GHz. It is therefore expect to improve the detection performance by suppressing the clutter using a pulse integration and CFAR (Constant False Alarm Rate). However the radar echo should include multiple vehicle targets as well as the clutter, thereby it is not easy to improve the performance. In this paper the target discrimination technique, let say, power delay profile matching scheme is proposed and the usefulness is investigated by conducting the measurement at 24GHz where the clutter suppression scheme is also considered. As a result, a vehicle target is found to be recognized from multiple vehicles. We have also investigated the effect of bandwidth on the target discrimination capability.

Stepped-FM UWB sensor system for health-care support

Health-care support at home and care facilities is a very important issue in many developed countries because of the arrival of increasingly aging society. The increase in accidents and sudden illness such as heart attach involving the elderly person is a matter of great concern and the requirement for monitoring their vital signs is especially increasing. In this work, we have developed a stepped-FM UWB sensor system which can detect the breathing rate as well as movement of multiple persons in a room. It estimates some trajectories of moving persons within a room, then localizes and monitors multiple persons. While sleeping, therefore, it can also detect the breathing rate from very tiny motions. Measurements were conducted for two scenarios with multiple subjects. The results show that the sensor system offers the breath monitoring and movement of multiple persons.