Achieving the capacity of half-duplex degraded relay channels using polar coding

In this paper, a novel transmission protocol based on polar coding is proposed for the half-duplex degraded relay channel. In the proposed protocol, referred to as the partial message relaying, the relay only needs to forward a part of the decoded source message that the destination needs according to the exquisite nested structure of polar codes. Theoretically, it is proved that the scheme can achieve the capacity of the half-duplex relay channel under the decode-and-forward （DF） cooperation strategy while enjoying low encoding/decoding complexity. Practically, in order to minimize the global transmission power, the optimization of the power allocation is performed between the source and the relay by using information theoretic tools. Furthermore, a joint iterative soft parallel interference cancellation receiver structure is developed to suit to the proposed scheme. Simulation results show that the proposed scheme outperforms the conventional scheme designed by low-density parity-check （LDPC） codes.     

EBAA：An efficient broadcast authentication scheme for ADS-B communication based on IBS-MR

Automatic dependent surveillance-broadcast （ADS-B） systems can broadcast satellitebased aircraft position, identification, etc., periodically, and are now on track to replace radar to become the backbone of next-generation air traffic management （ATM） systems. However, ADS-B systems suffer severe cyber-security problems due to the broadcast-type data link and the lack of designed-in security measures. Especially, since ADS-B messages are unauthenticated, it is easy to insert fake aircraft into a system via spoofing or insertion of false messages. Unfortu- nately, the authentication for ADS-B messages has not yet been well studied. In this paper, based on identity-based signature with message recovery （IBS-MR）, an efficient broadcast authentication scheme for ADS-B messages is proposed. The security analysis demonstrates that the scheme can achieve authenticity and integrity of ADS-B broadcast messages, as well as adaptive evolution of broadcasters＇ private keys. The performance evaluation shows that the scheme is computationally efficient for typical avionics devices with limited resources. Furthermore, the scheme achieves low communication overhead since broadcast messages can be recovered from signatures, and thus it is suitable for low-bandwidth ADS-B data link.     

Multi-view space object recognition and pose estimation based on kernel regression

The application of high-performance imaging sensors in space-based space surveillance systems makes it possible to recognize space objects and estimate their poses using vision-based methods. In this paper, we proposed a kernel regression-based method for joint multi-view space object recognition and pose estimation. We built a new simulated satellite image dataset named BUAA-SID 1.5 to test our method using different image representations. We evaluated our method for recognition-only tasks, pose estimation-only tasks, and joint recognition and pose estimation tasks. Experimental results show that our method outperforms the state-of-the-arts in space object recognition, and can recognize space objects and estimate their poses effectively and robustly against noise and lighting conditions.     

Optimal guidance of extended trajectory shaping

To control missile＇s miss distance as well as terminal impact angle, by involving the timeto-go-nth power in the cost function, an extended optimal guidance law against a constant maneuvering target or a stationary target is proposed using the linear quadratic optimal control theory.An extended trajectory shaping guidance（ETSG） law is then proposed under the assumption that the missile-target relative velocity is constant and the line of sight angle is small. For a lag-free ETSG system, closed-form solutions for the missile＇s acceleration command are derived by the method of Schwartz inequality and linear simulations are performed to verify the closed-form results. Normalized adjoint systems for miss distance and terminal impact angle error are presented independently for stationary targets and constant maneuvering targets, respectively. Detailed discussions about the terminal misses and impact angle errors induced by terminal impact angle constraint, initial heading error, seeker zero position errors and target maneuvering, are performed.     

异地遥测对接可行性探究

针对现有飞行器测控系统遥测对接试验周期长、效率低的不足,提出一种异地遥测对接方法.通过构建异地遥测对接系统结构,得到异地遥测对接信号链路模型.基于系统时钟抖动的频率、相位和采样时间表达形式,对异地遥测对接链路中的信号进行了具体推导.在此基础上,从频率和相位2个方面,定量分析了系统时钟抖动对异地遥测对接信号相参性的影响.分析结果表明：对于Ka频段信号,当应答机端异地遥测对接系统的时钟短期频率稳定度优于1×10^-11时,异地遥测对接系统引入的频率抖动△f≤0.6 Hz,相位抖动△φ≤0.075 rad,可认为异地遥测对接信号的相参性不受影响,异地遥测对接可行.     

多输入多输出雷达的非均匀线性阵列配置(英文)

提出了利用非均匀线性阵列(Non-uniform linear array,NLA)对多输入多输出(Multiple-input multipleoutput,MIMO)雷达系统进行阵列配置优化的方法。在传统的相控阵雷达中,非均匀线性阵列配置被用来形成较窄的波束方向图,而在MIMO雷达中,利用非均匀线性阵列来获得更多的互不相同的虚拟阵元,以此来提高雷达的参数可辨识性能。文中所采用的一种非均匀线性阵列是最小冗余线性阵列,并给出了一种在物理阵元数量较大时最小冗余线性阵列的生成方法。实验结果表明:与均匀线性阵列(Uniform linear array,ULA)配置的MIMO雷达相比,非均匀线性阵列MIMO雷达能够利用较少的物理天线阵元获得相同的参数可辨识性能;而在两种配置的雷达系统的物理阵元个数相同的情况下,非均匀线性阵列MIMO雷达可以获得更大的阵列孔径长度和更低的克拉美.罗界。     

航行情报服务教学模式的研究

针对目前航行情报服务教学中遇到的一些问题,提出在教学过程中采用目标任务教学方法,理论与实践渗透式的教学模式,激发学生学习兴趣,培养学生理论与实践相结合的能力,进一步提高学生综合运用专业知识的能力,从而达到航行情报服务的预期教学目标。     

单站无源定位中角度变化率的测量方法研究

讨论了单站无源定位中角度变化率测量的问题.首先简要介绍了差分法、最小二乘拟合法和卡尔曼滤波法的测量原理,其次为了解决滤波模型非线性的影响,提出了一种并行分段处理的卡尔曼滤波方法,最后从数字滤波的角度,通过设计相应的低通滤波器对估计获得的角度变化率数据流进行处理,进一步提高了角度变化率的测量精度.仿真实验对比分析了所述几...     

反辐射导弹趋向多目标打击能力

美国的新型反辐射导弹AARGM已经具备了打击非辐射源目标的多目标打击能力,这种能力将给反辐射导弹作战领域带来革命性的变化。近年来,以多模导引头技术、多模战斗部技术为代表的多种相关技术发展迅速,反辐射导弹正在进入一个崭新的＂多目标＂发展时期。     

预警机作战使用初探

预警机具有巨大的战争价值，对预警机的种类和装备的国家进行了介绍，用战例对预警机的战略预警任务、战术使用和其它用途进行了分析，尤其是在几场局部战争中预警机的应用。最后对预警机的发展简单阐述了看法。