In the present work, a direction of arrival estimator, under spread spectrum reference of signal-assisted radio operating in a Rayleigh fading channel, is proposed. The analysis, which is applied to general receiver a...In the present work, a direction of arrival estimator, under spread spectrum reference of signal-assisted radio operating in a Rayleigh fading channel, is proposed. The analysis, which is applied to general receiver antenna array configurations, demonstrates the high performance of the estimator which is due to the double dispreading (code word and reference signal). The probability distribution function of the estimator is extracted and the system’s robustness in regard to large number of interferers is demonstrated.展开更多
In wireless communication environment, the time-varying channel and angular spreads caused by multipath fading and the mobility of Mobile Stations (MS) degrade the performance of the conventional Direction-Of-Arrival ...In wireless communication environment, the time-varying channel and angular spreads caused by multipath fading and the mobility of Mobile Stations (MS) degrade the performance of the conventional Direction-Of-Arrival (DOA) tracking algorithms. On the other hand, although the DOA estimation methods based on the Maximum Likelihood (ML) principle have higher resolution than the beamforming and the subspace based methods, prohibitively heavy computation limits their practical applications. This letter first proposes a new suboptimal DOA estimation algorithm that combines the advantages of the lower complexity of subspace algorithm and the high accuracy of ML based algo- rithms, and then proposes a Kalman filtering based tracking algorithm to model the dynamic property of directional changes for mobile terminals in such a way that the association between the estimates made at different time points is maintained. At each stage during tracking process, the current suboptimal estimates of DOA are treated as measurements, predicted and updated via a Kalman state equation, hence adaptive tracking of moving MS can be carried out without the need to perform unduly heavy computations. Computer simulation results show that this proposed algorithm has better per- formance of DOA estimation and tracking of MS than the conventional ML or subspace based algo- rithms in terms of accuracy and robustness.展开更多
智能天线的一项核心技术是波达方向(Direction of Arrival,DOA)的估计,它在无线定位的应用领域中有着十分重要的意义.为了对信号的DOA作出精确的估计,提出一种基于空间平滑技术的改进型MUSIC(Multiple Signal Classification)算法.仿真...智能天线的一项核心技术是波达方向(Direction of Arrival,DOA)的估计,它在无线定位的应用领域中有着十分重要的意义.为了对信号的DOA作出精确的估计,提出一种基于空间平滑技术的改进型MUSIC(Multiple Signal Classification)算法.仿真结果表明经典的MUSIC算法只能对非相干信号的DOA作出精确的估计,而改进型MUSIC算法对相干信号的DOA也能作出精确的估计.展开更多
受多径传输环境的影响,在智能天线测向研究中,必须考虑相干信源的存在。针对相干信源的波达方向(Direction of Arrival,DoA)估计问题,提出了一种基于虚拟阵列平移的改进MUSIC算法。仿真结果表明:在相干信源入射角度差异很小(约5°)...受多径传输环境的影响,在智能天线测向研究中,必须考虑相干信源的存在。针对相干信源的波达方向(Direction of Arrival,DoA)估计问题,提出了一种基于虚拟阵列平移的改进MUSIC算法。仿真结果表明:在相干信源入射角度差异很小(约5°)的情况下,该算法依然能准确地估计;同时,该算法不损失阵列孔径,最多可估计出M-1(M为阵元数)个相干信源;此外,该算法具有同时适用于相干信源和非相干信源目标方位估计的优点。展开更多
In order to determine an appropriate attitude of three-axis stabilized communication satellites, this paper describes a novel attitude determination method using direction of arrival （DOA） estimation of a ground sig...In order to determine an appropriate attitude of three-axis stabilized communication satellites, this paper describes a novel attitude determination method using direction of arrival （DOA） estimation of a ground signal source. It differs from optical measurement, magnetic field measurement, inertial measurement, and global positioning system （GPS） attitude determination. The proposed method is characterized by taking the ground signal source as the attitude reference and acquiring attitude information from DOA estimation. Firstly, an attitude measurement equation with DOA estimation is derived in detail. Then, the error of the measurement equation is analyzed. Finally, an attitude determination algorithm is presented using a dynamic model, the attitude measurement equation, and measurement errors. A developing low Earth orbit （LEO） satellite which tests mobile communication technology with smart antennas can be stabilized in three axes by corporately using a magnetometer, reaction wheels, and three-axis magnetorquer rods. Based on the communication satellite, simulation results demonstrate the effectiveness of the method. The method could be a backup of attitude determination to prevent a system failure on the satellite. Its precision depends on the number of snapshots and the input signal-to-noise ratio （SNR） with DOA estimation.展开更多
提出了一种针对空间非相关窄带信号源的中心频率、方位角和俯仰角三维参数的同时估计方法。该方法通过对均匀双平行线阵时域采样构造虚拟阵元,然后结合空域采样数据构造时空DOA 矩阵,对 DOA 矩阵进行特征分解,利用分解得到的特征值和特...提出了一种针对空间非相关窄带信号源的中心频率、方位角和俯仰角三维参数的同时估计方法。该方法通过对均匀双平行线阵时域采样构造虚拟阵元,然后结合空域采样数据构造时空DOA 矩阵,对 DOA 矩阵进行特征分解,利用分解得到的特征值和特征向量估计出信号源的三维参数。该方法不需要进行谱峰搜索,运算量小,能实现频率、方位角和俯仰角的同时估计与自动配对,具有较高的分辨率,且能估计出比阵元数多的信号源的参数,给出的计算机仿真结果证明了该方法的有效性。展开更多
文摘In the present work, a direction of arrival estimator, under spread spectrum reference of signal-assisted radio operating in a Rayleigh fading channel, is proposed. The analysis, which is applied to general receiver antenna array configurations, demonstrates the high performance of the estimator which is due to the double dispreading (code word and reference signal). The probability distribution function of the estimator is extracted and the system’s robustness in regard to large number of interferers is demonstrated.
文摘In wireless communication environment, the time-varying channel and angular spreads caused by multipath fading and the mobility of Mobile Stations (MS) degrade the performance of the conventional Direction-Of-Arrival (DOA) tracking algorithms. On the other hand, although the DOA estimation methods based on the Maximum Likelihood (ML) principle have higher resolution than the beamforming and the subspace based methods, prohibitively heavy computation limits their practical applications. This letter first proposes a new suboptimal DOA estimation algorithm that combines the advantages of the lower complexity of subspace algorithm and the high accuracy of ML based algo- rithms, and then proposes a Kalman filtering based tracking algorithm to model the dynamic property of directional changes for mobile terminals in such a way that the association between the estimates made at different time points is maintained. At each stage during tracking process, the current suboptimal estimates of DOA are treated as measurements, predicted and updated via a Kalman state equation, hence adaptive tracking of moving MS can be carried out without the need to perform unduly heavy computations. Computer simulation results show that this proposed algorithm has better per- formance of DOA estimation and tracking of MS than the conventional ML or subspace based algo- rithms in terms of accuracy and robustness.
文摘智能天线的一项核心技术是波达方向(Direction of Arrival,DOA)的估计,它在无线定位的应用领域中有着十分重要的意义.为了对信号的DOA作出精确的估计,提出一种基于空间平滑技术的改进型MUSIC(Multiple Signal Classification)算法.仿真结果表明经典的MUSIC算法只能对非相干信号的DOA作出精确的估计,而改进型MUSIC算法对相干信号的DOA也能作出精确的估计.
文摘受多径传输环境的影响,在智能天线测向研究中,必须考虑相干信源的存在。针对相干信源的波达方向(Direction of Arrival,DoA)估计问题,提出了一种基于虚拟阵列平移的改进MUSIC算法。仿真结果表明:在相干信源入射角度差异很小(约5°)的情况下,该算法依然能准确地估计;同时,该算法不损失阵列孔径,最多可估计出M-1(M为阵元数)个相干信源;此外,该算法具有同时适用于相干信源和非相干信源目标方位估计的优点。
基金co-supported by the National Natural Science Foundation of China (No. 61073012)the Aeronautical Science Foundation of China (No. 20111951015)
文摘In order to determine an appropriate attitude of three-axis stabilized communication satellites, this paper describes a novel attitude determination method using direction of arrival （DOA） estimation of a ground signal source. It differs from optical measurement, magnetic field measurement, inertial measurement, and global positioning system （GPS） attitude determination. The proposed method is characterized by taking the ground signal source as the attitude reference and acquiring attitude information from DOA estimation. Firstly, an attitude measurement equation with DOA estimation is derived in detail. Then, the error of the measurement equation is analyzed. Finally, an attitude determination algorithm is presented using a dynamic model, the attitude measurement equation, and measurement errors. A developing low Earth orbit （LEO） satellite which tests mobile communication technology with smart antennas can be stabilized in three axes by corporately using a magnetometer, reaction wheels, and three-axis magnetorquer rods. Based on the communication satellite, simulation results demonstrate the effectiveness of the method. The method could be a backup of attitude determination to prevent a system failure on the satellite. Its precision depends on the number of snapshots and the input signal-to-noise ratio （SNR） with DOA estimation.
文摘提出了一种针对空间非相关窄带信号源的中心频率、方位角和俯仰角三维参数的同时估计方法。该方法通过对均匀双平行线阵时域采样构造虚拟阵元,然后结合空域采样数据构造时空DOA 矩阵,对 DOA 矩阵进行特征分解,利用分解得到的特征值和特征向量估计出信号源的三维参数。该方法不需要进行谱峰搜索,运算量小,能实现频率、方位角和俯仰角的同时估计与自动配对,具有较高的分辨率,且能估计出比阵元数多的信号源的参数,给出的计算机仿真结果证明了该方法的有效性。
