This paper addresses the probability of atmospheric refractivity estimation by using field measurements at an array of radio receivers in terms of angle-of-arrival spectrum. Angle-of-arrival spectrum information is si...This paper addresses the probability of atmospheric refractivity estimation by using field measurements at an array of radio receivers in terms of angle-of-arrival spectrum. Angle-of-arrival spectrum information is simulated by the ray optics model and refractivity is expressed in the presence of an ideal tri-linear profile. The estimation of the refractivity is organized as an optimization problem and a genetic Mgorithm is used to search for the optimal solution from various trial refractivity profiles. Theoretical analysis demonstrates the feasibility of this method to retrieve the refractivity parameters. Simulation results indicate that this approach has a fair anti-noise ability and its accuracy performance is mainly dependent on the antenna aperture size and its positions.展开更多
This paper presents a dual-band planar antenna array for ISM band applications (2.4 GHz and 2.45 GHz). This antenna is proposed for indoor applications and enables adaptive beamforming and angle of arrival (AOA) estim...This paper presents a dual-band planar antenna array for ISM band applications (2.4 GHz and 2.45 GHz). This antenna is proposed for indoor applications and enables adaptive beamforming and angle of arrival (AOA) estimation. An adaptive beamforming algorithm is applied for a planar antenna array, which is able to steer its main beam and nulls in azimuth and elevation planes over a wide frequency band. Planar antenna array operates as a spatial filter in 3D space, processing the received signals with weighting schemes. A planar antenna array is designed for AOA estimation in azimuth and elevation planes by using MUltiple SIgnal Classification (MUSIC) based on subspace algorithm. The Base Station (BS) equipped with this planar antenna is preferred to be at the center position on the room ceiling to cover all sectors of the room. It is designed to use four directional triangular elements arranged to form a square planar antenna array. Planar antenna with four elliptical slotted triangular elements (PAFESTE) is used to obtain optimal directivity in four directions in azimuth plane with specific orientation of 30? in elevation plane. It is characterized by half power beamwidth in elevation plane of about 60? and half power beamwidth in azimuth plane of about 90?.展开更多
The increasingly widespread use of sensor and actuator networks and in general of the Internet of Things (IoT) in several areas of precision, imposes upon localization systems that can often equip them with a robust a...The increasingly widespread use of sensor and actuator networks and in general of the Internet of Things (IoT) in several areas of precision, imposes upon localization systems that can often equip them with a robust and more precise localization. It is in this sense that UWB technology has proved to be one of the most powerful communication technologies for these localization systems;thanks, in particular to the bandwidth occupied instantaneously by the signal allowing a very fine temporal resolution. Constructors have set up localization kits based on various technologies. These kits facilitate in a way the work of localization of users. In this paper, we present results on the performance study of the Decawave PDoA Kit. This Kit uses the PDoA (Phase Difference of Arrival) to determine the Angle of Arrival (AoA) parameter with UWB technology. This study is in context of localization by AoA for an application to protect agricultural crops against grain-eating birds. The results of the study show overall AoA measurement errors around 10 degrees in an ideal environment.展开更多
Mobile location using angle of arrival （AOA） measurements has received considerable attention. This paper presents an approximation of maximum likelihood estimator （MLE） for localizing a source based on AOA measur...Mobile location using angle of arrival （AOA） measurements has received considerable attention. This paper presents an approximation of maximum likelihood estimator （MLE） for localizing a source based on AOA measurements. By introducing an intermediate variable, the nonlinear equations relating AOA estimates can be transformed into a set of equations which are linear in the unknown parameters. It is an approximate realization of the MLE. Simulations show that the proposed algorithm outperforms the previous contribution.展开更多
As one of the major methods for location positioning, angle-of-arrival (AOA) estimation is a significant technology in radar, sonar, radio astronomy, and mobile communications. AOA measurements can be exploited to loc...As one of the major methods for location positioning, angle-of-arrival (AOA) estimation is a significant technology in radar, sonar, radio astronomy, and mobile communications. AOA measurements can be exploited to locate mobile units, enhance communication efficiency and network capacity, and support location-aided routing, dynamic network management, and many location-based services. In this paper, we propose an algorithm for AOA estimation in colored noise fields and harsh application scenarios. By modeling the unknown noise covariance as a linear combination of known weighting matrices, a maximum likelihood (ML) criterion is established, and a particle swarm optimization (PSO) paradigm is designed to optimize the cost function. Simulation results demonstrate that the paired estimator PSO-ML significantly outperforms other popular techniques and produces superior AOA estimates.展开更多
为了解决传统室内定位技术成本较高、稳定性差以及难于部署等问题,提出一种将到达时间(time of arrival,TOA)与到达角(angle of arrival,AOA)相结合的室内定位系统.该系统由定位基站与被控定位单元组成,其特征在于使用对射式布置的超声...为了解决传统室内定位技术成本较高、稳定性差以及难于部署等问题,提出一种将到达时间(time of arrival,TOA)与到达角(angle of arrival,AOA)相结合的室内定位系统.该系统由定位基站与被控定位单元组成,其特征在于使用对射式布置的超声波传感器获取定位基站与被控定位单元之间的距离特征,利用角度传感器获取被控定位单元相对于定位基站的角度特征,以单基站就实现了精确的室内定位过程.分析了该系统基本结构与原理,建立定位与控制模型,在一定范围内对其定点定位精度与跟随定位精度进行了实验验证.实验结果表明:该系统结构简单,易于安装布置,鲁棒性强,在测试范围内的最大定点定位误差不超过5 cm,跟随定位误差不超过15 cm.展开更多
提出一种基于超宽带(ultra wideband,UWB)信号到达时间估计(time of arrival,TOA)/到达角度估计(angle of arrival,AOA)联合估计的无线传感器网络(wireless sensor networks,WSNs)定位方案,只需要一个参考节点就可以实现对其他传感器节...提出一种基于超宽带(ultra wideband,UWB)信号到达时间估计(time of arrival,TOA)/到达角度估计(angle of arrival,AOA)联合估计的无线传感器网络(wireless sensor networks,WSNs)定位方案,只需要一个参考节点就可以实现对其他传感器节点的2D相对定位,并且不需要时钟同步,适合于传感器网络节点的低成本设计需求.利用往返时间(round trip time,RTT)进行TOA估计,给出了基于多径检测的TOA估计算法;利用到达时间差估计(time difference of arrival,TDOA)进行AOA估计,因而无需借助复杂的天线波束赋形技术.同时,分析了定位误差模型对定位性能的影响,并通过IEEE802.15.4a信道下的仿真实验进行了验证,结果表明了所提方案的有效性.展开更多
为了提高室内三维空间的定位精度,提出了一种基于联合到达时间差与到达角度(time difference of arrival/angle of arrival,TDOA/AOA)信息的混合定位算法。由于构建的目标函数具有非凸性,采用传统定位算法在目标函数求解过程中会出现局...为了提高室内三维空间的定位精度,提出了一种基于联合到达时间差与到达角度(time difference of arrival/angle of arrival,TDOA/AOA)信息的混合定位算法。由于构建的目标函数具有非凸性,采用传统定位算法在目标函数求解过程中会出现局部最优解的问题。因此,针对该问题,将目标函数转成二次约束二次规划问题,通过引入半定松弛(semi-definite relaxation,SDR)方法将目标函数转换为二阶锥规划(second order cone programming,SOCP)问题,寻找全局最优解。其次,针对SOCP无法对凸包外的目标进行有效定位的问题,在该算法的基础上引入了惩罚项,使松弛后的约束条件进一步逼近原始约束条件,解决了定位过程中的凸包问题。数值仿真结果表明:在10m×10m×3m的三维定位空间内,选取40×40个测试点,平均定位误差为1.39cm,可实现室内三维空间高精度定位。与传统的混合定位算法相比,均能够获得较高的定位精度。展开更多
针对某些特殊的微小区移动通信环境,比如空旷的广场或者大型购物商厦等,移动台(Mobile station,MS)周围散射体可能很少,甚至于为零,在已有模型基础上建立了一种新的3-D空间模型——空心半球体空间模型。散射体均匀分布在移动台附近空间...针对某些特殊的微小区移动通信环境,比如空旷的广场或者大型购物商厦等,移动台(Mobile station,MS)周围散射体可能很少,甚至于为零,在已有模型基础上建立了一种新的3-D空间模型——空心半球体空间模型。散射体均匀分布在移动台附近空间内,而基站(Base station,BS)的位置在离地面有一定的高度。在水平平面和垂直平面内分别推导出来波信号的到达角度(Angle of arrival,AOA)的概率密度函数表达式,另外也研究了信号到达时间(Time of arrival,TOA)的概率密度函数。估计结果与某些2-D和3-D模型对比,表明本模型的信道参数估计符合以往的理论,对空间统计信道模型的研究和应用提供了有效的支持与拓展。展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 40775023)
文摘This paper addresses the probability of atmospheric refractivity estimation by using field measurements at an array of radio receivers in terms of angle-of-arrival spectrum. Angle-of-arrival spectrum information is simulated by the ray optics model and refractivity is expressed in the presence of an ideal tri-linear profile. The estimation of the refractivity is organized as an optimization problem and a genetic Mgorithm is used to search for the optimal solution from various trial refractivity profiles. Theoretical analysis demonstrates the feasibility of this method to retrieve the refractivity parameters. Simulation results indicate that this approach has a fair anti-noise ability and its accuracy performance is mainly dependent on the antenna aperture size and its positions.
文摘This paper presents a dual-band planar antenna array for ISM band applications (2.4 GHz and 2.45 GHz). This antenna is proposed for indoor applications and enables adaptive beamforming and angle of arrival (AOA) estimation. An adaptive beamforming algorithm is applied for a planar antenna array, which is able to steer its main beam and nulls in azimuth and elevation planes over a wide frequency band. Planar antenna array operates as a spatial filter in 3D space, processing the received signals with weighting schemes. A planar antenna array is designed for AOA estimation in azimuth and elevation planes by using MUltiple SIgnal Classification (MUSIC) based on subspace algorithm. The Base Station (BS) equipped with this planar antenna is preferred to be at the center position on the room ceiling to cover all sectors of the room. It is designed to use four directional triangular elements arranged to form a square planar antenna array. Planar antenna with four elliptical slotted triangular elements (PAFESTE) is used to obtain optimal directivity in four directions in azimuth plane with specific orientation of 30? in elevation plane. It is characterized by half power beamwidth in elevation plane of about 60? and half power beamwidth in azimuth plane of about 90?.
文摘The increasingly widespread use of sensor and actuator networks and in general of the Internet of Things (IoT) in several areas of precision, imposes upon localization systems that can often equip them with a robust and more precise localization. It is in this sense that UWB technology has proved to be one of the most powerful communication technologies for these localization systems;thanks, in particular to the bandwidth occupied instantaneously by the signal allowing a very fine temporal resolution. Constructors have set up localization kits based on various technologies. These kits facilitate in a way the work of localization of users. In this paper, we present results on the performance study of the Decawave PDoA Kit. This Kit uses the PDoA (Phase Difference of Arrival) to determine the Angle of Arrival (AoA) parameter with UWB technology. This study is in context of localization by AoA for an application to protect agricultural crops against grain-eating birds. The results of the study show overall AoA measurement errors around 10 degrees in an ideal environment.
文摘Mobile location using angle of arrival （AOA） measurements has received considerable attention. This paper presents an approximation of maximum likelihood estimator （MLE） for localizing a source based on AOA measurements. By introducing an intermediate variable, the nonlinear equations relating AOA estimates can be transformed into a set of equations which are linear in the unknown parameters. It is an approximate realization of the MLE. Simulations show that the proposed algorithm outperforms the previous contribution.
文摘As one of the major methods for location positioning, angle-of-arrival (AOA) estimation is a significant technology in radar, sonar, radio astronomy, and mobile communications. AOA measurements can be exploited to locate mobile units, enhance communication efficiency and network capacity, and support location-aided routing, dynamic network management, and many location-based services. In this paper, we propose an algorithm for AOA estimation in colored noise fields and harsh application scenarios. By modeling the unknown noise covariance as a linear combination of known weighting matrices, a maximum likelihood (ML) criterion is established, and a particle swarm optimization (PSO) paradigm is designed to optimize the cost function. Simulation results demonstrate that the paired estimator PSO-ML significantly outperforms other popular techniques and produces superior AOA estimates.
文摘为了解决传统室内定位技术成本较高、稳定性差以及难于部署等问题,提出一种将到达时间(time of arrival,TOA)与到达角(angle of arrival,AOA)相结合的室内定位系统.该系统由定位基站与被控定位单元组成,其特征在于使用对射式布置的超声波传感器获取定位基站与被控定位单元之间的距离特征,利用角度传感器获取被控定位单元相对于定位基站的角度特征,以单基站就实现了精确的室内定位过程.分析了该系统基本结构与原理,建立定位与控制模型,在一定范围内对其定点定位精度与跟随定位精度进行了实验验证.实验结果表明:该系统结构简单,易于安装布置,鲁棒性强,在测试范围内的最大定点定位误差不超过5 cm,跟随定位误差不超过15 cm.
文摘提出一种基于超宽带(ultra wideband,UWB)信号到达时间估计(time of arrival,TOA)/到达角度估计(angle of arrival,AOA)联合估计的无线传感器网络(wireless sensor networks,WSNs)定位方案,只需要一个参考节点就可以实现对其他传感器节点的2D相对定位,并且不需要时钟同步,适合于传感器网络节点的低成本设计需求.利用往返时间(round trip time,RTT)进行TOA估计,给出了基于多径检测的TOA估计算法;利用到达时间差估计(time difference of arrival,TDOA)进行AOA估计,因而无需借助复杂的天线波束赋形技术.同时,分析了定位误差模型对定位性能的影响,并通过IEEE802.15.4a信道下的仿真实验进行了验证,结果表明了所提方案的有效性.
文摘为了提高室内三维空间的定位精度,提出了一种基于联合到达时间差与到达角度(time difference of arrival/angle of arrival,TDOA/AOA)信息的混合定位算法。由于构建的目标函数具有非凸性,采用传统定位算法在目标函数求解过程中会出现局部最优解的问题。因此,针对该问题,将目标函数转成二次约束二次规划问题,通过引入半定松弛(semi-definite relaxation,SDR)方法将目标函数转换为二阶锥规划(second order cone programming,SOCP)问题,寻找全局最优解。其次,针对SOCP无法对凸包外的目标进行有效定位的问题,在该算法的基础上引入了惩罚项,使松弛后的约束条件进一步逼近原始约束条件,解决了定位过程中的凸包问题。数值仿真结果表明:在10m×10m×3m的三维定位空间内,选取40×40个测试点,平均定位误差为1.39cm,可实现室内三维空间高精度定位。与传统的混合定位算法相比,均能够获得较高的定位精度。
文摘针对某些特殊的微小区移动通信环境,比如空旷的广场或者大型购物商厦等,移动台(Mobile station,MS)周围散射体可能很少,甚至于为零,在已有模型基础上建立了一种新的3-D空间模型——空心半球体空间模型。散射体均匀分布在移动台附近空间内,而基站(Base station,BS)的位置在离地面有一定的高度。在水平平面和垂直平面内分别推导出来波信号的到达角度(Angle of arrival,AOA)的概率密度函数表达式,另外也研究了信号到达时间(Time of arrival,TOA)的概率密度函数。估计结果与某些2-D和3-D模型对比,表明本模型的信道参数估计符合以往的理论,对空间统计信道模型的研究和应用提供了有效的支持与拓展。
