This paper proposes a unified clutter model incorporating the effects of range walk and array rotation for space-time adaptive processing（STAP） in airborne multi-channel early-warning radar.Based on this clutter mod...This paper proposes a unified clutter model incorporating the effects of range walk and array rotation for space-time adaptive processing（STAP） in airborne multi-channel early-warning radar.Based on this clutter model,STAP performance is then analyzed from the perspective of covariance matrix tapering（CMT）.For STAP performance degradation due to array rotation,a determinate compensation method is proposed based on the CMT method.Numerical examples are provided to verify the analysis and the proposed compensation method.展开更多
In non-homogeneous environment, traditional space-time adaptive processing doesn＇t effectively suppress interference and detect target, because the secondary data don＇ t exactly reflect the statistical characteristi...In non-homogeneous environment, traditional space-time adaptive processing doesn＇t effectively suppress interference and detect target, because the secondary data don＇ t exactly reflect the statistical characteristic of the range cell under test. A ravel methodology utilizing the direct data domain approach to space-time adaptive processing （ STAP ） in airbome radar non-homogeneous environments is presented. The deterministic least squares adaptive signal processing technique operates on a ＂snapshot-by-snapshot＂ basis to dethrone the adaptive adaptive weights for nulling interferences and estimating signal of interest （SOI）. Furthermore, this approach eliminates the requirement for estimating the covariance through the data of neighboring range cell, which eliminates calculating the inverse of covariance, and can be implemented to operate in real-time. Simulation results illustrate the efficiency of interference suppression in non-homogeneous environment.展开更多
Adaptive broadband beamforraing is a key issue in array applications. The adaptive broadband beamformer with tapped delay line （TDL） structure for nonuniform linear array （NLA） is designed according to the rule of...Adaptive broadband beamforraing is a key issue in array applications. The adaptive broadband beamformer with tapped delay line （TDL） structure for nonuniform linear array （NLA） is designed according to the rule of minimizing the beamformer＇s output power while keeping the distortionless response （DR） in the direction of desired signal and keeping the constant beamwidth （CB） with the prescribed sidelobe level over the whole operating band. This kind of beamforming problem can be solved with the interior-point method after being converted to the form of standard second order cone programming （SOCP）. The computer simulations are presented which illustrate the effectiveness of our beamformer.展开更多
Adaptive antenna arrays have been used to mitigate the interference on global navigation satellite system（GNSS） receivers. The performance of interference mitigation depends on the beamforming algorithms adopted by ...Adaptive antenna arrays have been used to mitigate the interference on global navigation satellite system（GNSS） receivers. The performance of interference mitigation depends on the beamforming algorithms adopted by the antenna array. However,the adaptive beamforming will change the array pattern in realtime, which has the potential to introduce phase center biases into the antenna array. For precise applications, these phase biases must be mitigated or compensated because they will bring errors in code phase and carrier phase measurements. A novel adaptive beamforming algorithm is proposed firstly, then the phase bias induced by the proposed algorithm is estimated, and finally a compensation strategy is addressed. Simulations demonstrate that the proposed beamforming algorithm suppresses effectively the strong interference and improves significantly the capturing performance of GNSS signals. Simultaneously, the bias compensation method avoids the loss of the carrier phase lock and reduces the phase measurement errors for GNSS receivers.展开更多
提出了一种基于信道估计与级数展开的均衡器阶数确定算法(equalizer order algorithm based on channel estimation andseries expansion,CESE-EOA)。自适应均衡器是相干水声通信系统的重要组成部分,其阶数参数的确定会对系统性能产生...提出了一种基于信道估计与级数展开的均衡器阶数确定算法(equalizer order algorithm based on channel estimation andseries expansion,CESE-EOA)。自适应均衡器是相干水声通信系统的重要组成部分,其阶数参数的确定会对系统性能产生重大影响。传统的均衡器阶数确定方法有适应性较差、对训练序列的长度要求较高等缺点。从多重线性回归模型的角度讨论了自适应均衡器阶数选择的依据,并以此为基础给出了一种最优的阶数计算方法,减小了均衡器的自噪声。理论分析与仿真、试验结果证明了该算法的正确性。该算法可用于计算线性自适应均衡器、盲均衡器或判决反馈均衡器中前馈滤波器的最优阶数,对均衡器设计有重要借鉴意义。展开更多
针对阵列信号波达角(direction of arrival,DOA)先验信息已知的情况,利用信号的恒模特性,在卡尔曼滤波(Kalman filter,KF)结构下,提出一种附加阵列导向矢量约束的自适应波束形成算法.对约束情况下的卡尔曼滤波目标函数运用拉格朗日乘子...针对阵列信号波达角(direction of arrival,DOA)先验信息已知的情况,利用信号的恒模特性,在卡尔曼滤波(Kalman filter,KF)结构下,提出一种附加阵列导向矢量约束的自适应波束形成算法.对约束情况下的卡尔曼滤波目标函数运用拉格朗日乘子法,求得约束条件下的最优估计表达式,并将其推广到无迹卡尔曼滤波(unscented Kalman filter,UKF)算法中,通过约束迭代算法对阵列估计信号的导向角施加约束,实现约束UKF自适应波束形成算法的最优权值分配.仿真过程中,用所提算法与约束恒模迭代最小二乘算法和约束最小方差迭代最小二乘算法作对比,表明表明,该算法在收敛速度、信噪比、稳健性、跟踪性能方面具有较好的性能.展开更多
基金supported by the National Natural Science Foundation of China(60901056)
文摘This paper proposes a unified clutter model incorporating the effects of range walk and array rotation for space-time adaptive processing（STAP） in airborne multi-channel early-warning radar.Based on this clutter model,STAP performance is then analyzed from the perspective of covariance matrix tapering（CMT）.For STAP performance degradation due to array rotation,a determinate compensation method is proposed based on the CMT method.Numerical examples are provided to verify the analysis and the proposed compensation method.
文摘In non-homogeneous environment, traditional space-time adaptive processing doesn＇t effectively suppress interference and detect target, because the secondary data don＇ t exactly reflect the statistical characteristic of the range cell under test. A ravel methodology utilizing the direct data domain approach to space-time adaptive processing （ STAP ） in airbome radar non-homogeneous environments is presented. The deterministic least squares adaptive signal processing technique operates on a ＂snapshot-by-snapshot＂ basis to dethrone the adaptive adaptive weights for nulling interferences and estimating signal of interest （SOI）. Furthermore, this approach eliminates the requirement for estimating the covariance through the data of neighboring range cell, which eliminates calculating the inverse of covariance, and can be implemented to operate in real-time. Simulation results illustrate the efficiency of interference suppression in non-homogeneous environment.
基金supported by the National Nature Science Foundation of China (60472101)President Award of ChineseAcademy of Sciences(O729031511).
文摘Adaptive broadband beamforraing is a key issue in array applications. The adaptive broadband beamformer with tapped delay line （TDL） structure for nonuniform linear array （NLA） is designed according to the rule of minimizing the beamformer＇s output power while keeping the distortionless response （DR） in the direction of desired signal and keeping the constant beamwidth （CB） with the prescribed sidelobe level over the whole operating band. This kind of beamforming problem can be solved with the interior-point method after being converted to the form of standard second order cone programming （SOCP）. The computer simulations are presented which illustrate the effectiveness of our beamformer.
基金supported by the National Natural Science Foundation of China(61301094)the Postdoctoral Science Foundation of China(2014M552490)
文摘Adaptive antenna arrays have been used to mitigate the interference on global navigation satellite system（GNSS） receivers. The performance of interference mitigation depends on the beamforming algorithms adopted by the antenna array. However,the adaptive beamforming will change the array pattern in realtime, which has the potential to introduce phase center biases into the antenna array. For precise applications, these phase biases must be mitigated or compensated because they will bring errors in code phase and carrier phase measurements. A novel adaptive beamforming algorithm is proposed firstly, then the phase bias induced by the proposed algorithm is estimated, and finally a compensation strategy is addressed. Simulations demonstrate that the proposed beamforming algorithm suppresses effectively the strong interference and improves significantly the capturing performance of GNSS signals. Simultaneously, the bias compensation method avoids the loss of the carrier phase lock and reduces the phase measurement errors for GNSS receivers.
文摘提出了一种基于信道估计与级数展开的均衡器阶数确定算法(equalizer order algorithm based on channel estimation andseries expansion,CESE-EOA)。自适应均衡器是相干水声通信系统的重要组成部分,其阶数参数的确定会对系统性能产生重大影响。传统的均衡器阶数确定方法有适应性较差、对训练序列的长度要求较高等缺点。从多重线性回归模型的角度讨论了自适应均衡器阶数选择的依据,并以此为基础给出了一种最优的阶数计算方法,减小了均衡器的自噪声。理论分析与仿真、试验结果证明了该算法的正确性。该算法可用于计算线性自适应均衡器、盲均衡器或判决反馈均衡器中前馈滤波器的最优阶数,对均衡器设计有重要借鉴意义。
