It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present...It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present a multi-ray propagation model for UWB signal,which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces,A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment.This model enables replication of time-varying multipath profiles due to the displacement of a human chest.Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate.The analytical framework can serve as a basis in the planning and evaluation of future rheasurement programs.We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture.展开更多
应用双偏振天气雷达探测天气信号的方法备受国内外气象科技领域人员的关注。目前,双偏振天气雷达的双通道同时收发体制是由功分器将发射通道的能量等分为水平和垂直两路发射通道,其结果会使每个通道发射能量减半,又由于接收机产生的噪...应用双偏振天气雷达探测天气信号的方法备受国内外气象科技领域人员的关注。目前,双偏振天气雷达的双通道同时收发体制是由功分器将发射通道的能量等分为水平和垂直两路发射通道,其结果会使每个通道发射能量减半,又由于接收机产生的噪音能量是不变的,必然引起回波信噪比减弱,减弱值约为3 d B。为了避免3 d B损失带来的不利影响,需改进双偏振雷达的探测性能。将双偏振雷达回波信号中的双通道信号间的互相关信息、单通道信号自身的信相关信息及每个信号自身的能量信息求和,再将结果与预先设置好的阈值进行比较。如果结果大于这个阈值,就认为这个信号是有效信号,否则就认为它是噪声并被滤除。文中利用X波段双偏振天气雷达数据,对比了引入互相关算法前后的探测效果,证明利用双通道信号互相关、单通道自相关及信号能量自身求和判断信号是否存在的效果较好;介绍了中值滤波技术,并利用中值滤波技术去除了天气回波中的点杂波,提高了双偏振天气雷达的探测性能。展开更多
文摘It has been shown that remote monitoring of pulmonary activity can be achieved using ultra-wideband (UWB) systems, which shows promise in home healthcare,rescue,and security applications.In this paper,we first present a multi-ray propagation model for UWB signal,which is traveling through the human thorax and is reflected on the air/dry-skin/fat/muscle interfaces,A geometry-based statistical channel model is then developed for simulating the reception of UWB signals in the indoor propagation environment.This model enables replication of time-varying multipath profiles due to the displacement of a human chest.Subsequently, a UWB distributed cognitive radar system (UWB-DCRS) is developed for the robust detection of chest cavity motion and the accurate estimation of respiration rate.The analytical framework can serve as a basis in the planning and evaluation of future rheasurement programs.We also provide a case study on how the antenna beamwidth affects the estimation of respiration rate based on the proposed propagation models and system architecture.
文摘应用双偏振天气雷达探测天气信号的方法备受国内外气象科技领域人员的关注。目前,双偏振天气雷达的双通道同时收发体制是由功分器将发射通道的能量等分为水平和垂直两路发射通道,其结果会使每个通道发射能量减半,又由于接收机产生的噪音能量是不变的,必然引起回波信噪比减弱,减弱值约为3 d B。为了避免3 d B损失带来的不利影响,需改进双偏振雷达的探测性能。将双偏振雷达回波信号中的双通道信号间的互相关信息、单通道信号自身的信相关信息及每个信号自身的能量信息求和,再将结果与预先设置好的阈值进行比较。如果结果大于这个阈值,就认为这个信号是有效信号,否则就认为它是噪声并被滤除。文中利用X波段双偏振天气雷达数据,对比了引入互相关算法前后的探测效果,证明利用双通道信号互相关、单通道自相关及信号能量自身求和判断信号是否存在的效果较好;介绍了中值滤波技术,并利用中值滤波技术去除了天气回波中的点杂波,提高了双偏振天气雷达的探测性能。
