Study On The Technology Of Non-contact Extracting Vital Signs Based On Ultra Wide Band Bioradar

Basing on bioradar, the non-contact detecting technology uses electromagnetic waves transmitted by radar to detect vital signs. Using this technology, we could detect the vital signs at some distance and penetrating some media such as clothes, gauze, brick wall, and so on. It is a new-style non-contact detecting technology. This technology can be widely applied in the field such as military medicine, disaster medicine (searching the wounded under wasteland), and counterattacking urban terror (monitoring hostages and criminals through wall). In the practice, we care not only whether the human beings exit, but also their vital signs, such as respiration signal, heartbeat signal and so on. But vital signs detected by bioradar are always random signals, they are also unstable. And the interferences from the surroundings are stronger than the vital signs. It is difficult for us to extract vital signs under the circumstance that the interferences are stronger. And, using this system, we can real-time detect superficial jiggle of human beings bring about by respiration and heartbeat. It is useful in practice especially in military medicine.When we use bioradar to monitor vital signs without contacting, the vital signs are always interfered by surroundings. And the energy of respiration is larger than the heartbeat's. The vital signs detected by radar are affected both by respiration and heartbeat. The respiration signal and the heartbeat signal are overlapped in frequency spectrum. According to the characteristics of respiration signal and heartbeat signal, when we use the normal filter, we can't separate them effectively. And the least-mean-square adaptive filters also can not have a good effect in unstable environment. The recursive-least-square adaptive filters aim at minimize the sum of error squares, where the error is of the desire signal and the filters'output signal. Its parameters can adjust to the change of environment, so as to carry out the best result gradually. It will make an excellent effect on processing stochastic biomedical signals. When the eigenvalue of the signal's correlation matrix spread is large, the convergence of the RLS filter may be fast, that is important to process signals in real-tine way.The main results are as follows:1. Established the system of non-contact vital signs detection based on ultra-wide-band radar, and programmed the software of non-contact detecting vital signs. We also proposed a calculation of the vital signs'frequency. Furthermore, we carried out real time monitoring the superficial jiggle caused by respiration and heartbeat, not only in disengagement space, but also penetrating a 30 centimeters thick brick wall.2. Established the system of synchronous signal collection, obtained electrocardiosignal, and compared with the non-contact detected heartbeat signal. And discussed the result of heartbeat signal extracted in non-contact way.3. Studied on adaptive filter theory, did many experiments. Under different circumstance, we used the RLS adaptive filter to extract the heartbeat signal without contact, and compared with the LMS adaptive filter.The thesis obtained some results as follows:1. Established the system of non-contact vital signs detection based on ultra-wide-band radar. The system can fulfill the function of real time monitoring the superficial jiggle caused by respiration and heartbeat, not only in disengagement space, but also penetrating a 30 centimeters thick brick wall.2. Used the recursive-least-square adaptive algorithm to separate respiration signal and heartbeat signal, which were detected by ultra-wide-band radar in non-contact way, and found out a useful method to separate respiration signal and heartbeat signal.