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Very large phased array antennas, particularly in radar and adaptive receive applications as opposed to communications usages, require large amounts of digital data processing for beamsteering, null-formation, imaging, and signal correlation computations. Such processing requires a computational capability which is effectively proportional to the square of the antenna size, and can readily become one of the main design drivers. This processing bottleneck problem is addressed for large phased array antennas. An approach in terms of parallel processing in the optical domain is presented as a potential solution. The defining equations for a phased array antenna system are given, along with the transfer functions for an embedded optical spatial filter control element. Such a control element is shown to have the potential of rapidly reconfiguring a large phased array antenna without the speed penalties associated with conventional sequential addressing methods. A hypothetical phased array antenna, with optical spatial filter control elements, is simulated in a computer model and performance results are presented 相似文献
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无线Mesh网技术是一种新的无线网络技术,其核心是任何无线设备节点都可以同时作为接入点(AP)和路由器,网络中的每个节点都可以发送和接收信号,每个节点都可以与一个或者多个对等节点进行直接通信。无线Mesh网中需要考虑完成通信的多跳过程中产生的数据传输可靠性的保障问题。使用第三代合作伙伴计划(3GPP)的系统架构中提出的混合自动重传请求(HARQ)和自动重传请求(ARQ)功能,可以对多跳链路数据可靠传输进行保障。其中针对HARQ提出了逐跳和端到端两种方法,而对于ARQ功能除了逐跳和端到端两种方法外还增加了最后一跳的保障机制。从协议栈构架设计的角度,根据HARQ和OARQ机制提出了3种解决方法:分层机制、Relay ARQ机制、多剧SARQ机制。 相似文献
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A model for the theoretical error bounds for the radiometric calibration of SAR imagery is described. The model is then applied utilizing the radar system parameters that will be used in the project PHARUS (Phased Array Universal SAR), a Dutch polarimetric airborne C -band universal SAR, which is currently under construction. An error model for the phased array antenna pattern is presented. This model was applied to a 16×8 phased array antenna to determine the influence of errors in the T/R modules and angle variations of the beam direction. For a wide range of variances the model is in good agreement with the exact solution, but with far less computer effort. Other, more complicated, antennas can be analyzed in a straightforward way. The model can be used as a design tool for digital phased array radar 相似文献
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相控阵雷达向集成化、小型化、轻量化方向发展,相控阵雷达综合网络的电气互联也随之需要向少/ 无引线方式转变。相控阵雷达综合网络中的微波馈电网络和波束控制网络的集成已通过微波数字混合多层印制板方式实现,而大电流电源分配网络的集成设计和制造已成为实现无引线阵面的关键。文中介绍了相控阵雷达综合网络集成式汇流板的设计和制造过程, 着重叙述了该集成式汇流板制造的关键技术,采用复合定位技术、层压封装技术实现了大电流汇流板的一体化制造,为相控阵雷达由有引线阵面向无引线阵面提供了基础,推动了相控阵雷达集成化和可靠性提升的进程。 相似文献
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In a wireless sensor network (WSN), after gathering information, tiny sensor nodes need to transmit data to a sink. It is important to guarantee that each node can communicate with a sink. Due to the multi-hop communication of WSNs, an essential condition for reliable transmission is completely connectivity of a network. Adaptive or smart antenna (SA) techniques in WSNs have been a topic of active research in recent years. These techniques have been shown to be effective with respect to decreasing energy consuming via specified regions which are formed by the SA beams. In this paper, we propose a probabilistic technique to determine the network connectivity probability of the SA integrated WSN. We employ the geometric shape model to evaluate the network connectivity probability of the WSN using the SA beam specifications. The sensor node density to satisfy the desired network connectivity is determined in terms of the beam-width of the antenna array and node transmission range. The analytical results agree with the simulation results by less than 4.7 % error in the average. 相似文献
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根据某三坐标相控阵雷达工作的特点,本文设计了一种Tws算法。该算法针对相控阵雷达变扫描周期的特点进行了适应性处理,针对不同目标模型状态变量不一致的问题进行了统一化的处理,并且在交互多模型算法中根据模型匹配程度动态调整模型的噪声协方差以达到更好的跟踪效果。该算法在雷达的实际跟踪试验中,取得了预期的效果。 相似文献
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Q. Md. Alfred T. Chakravarty G. Singh S. K. Sanyal 《Journal of Infrared, Millimeter and Terahertz Waves》2007,28(10):881-887
In radar, planar phased array antenna plays vital role in electronic scanning in the azimuth and elevation direction to the horizon. In most operations using planar phased array both the coordinates of azimuth and elevation, are steered electronically. In this paper a conceptual schematic of a phased array antenna with programmable time delay units has been presented. It is shown that by suitably exploiting the time delay matrix one can have electronic beam rotation around the target axis as required in conical scan. Thus both the elevation and azimuth motors in conical scan system are replaced by electronic scanning. Heuristically, we have selected eight consecutive points for beam rotation in a polygon shape and can also be extended almost circular shape by increasing number of array elements and phase shifter (delays) in the delay matrix. The array requires dual control of phase gradient and individual phase values. The whole array is controlled by micro-controller. This presents exciting possibilities in radar operation. 相似文献
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从技术上探求了基于STK平台的相控阵雷达截获IKONOS卫星的方法。简要介绍了IKONOS卫星的基本信息及部分参数,并给出了基于STK的相控阵雷达空间目标监视模型,分析了基于STK的相控阵雷达空间目标监视模型搜索屏的仰角与截获IKONOS卫星次数的关系,为有效监视IKONOS卫星提供了重要依据。 相似文献
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本文介绍了一种利用组件化建模的思想的舰载相控阵雷达信号处理的仿真建模方法。 首先,按照功能对舰载相控阵雷达信号处理进行了功能组件划分,介绍了基于 C++语言的舰载相控阵信号处理仿真系统的构建方法,使其具备可复用性、可重构性与可扩展性。接着对舰载相控阵雷达的信号处理进行了信号级仿真,通过对仿真的结果进行精度分析与性能评估,验证了模型的准确性。建立的舰载相控阵雷达信号处理模型为舰载相控阵雷达的仿真与应用提供了良好的基础,在工程上具有一定的参考意义。 相似文献
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相控阵天线的布线设计,一直是相控阵天线的设计关键,布线方案的成功与否将直接影响雷达的可靠性指标及维修性指标。文中从一种相控阵天线的方案着手,在狭小的尺寸空间内进行布线,采取了多级导向盲插的方法改善相控阵天线的维修性,并详细介绍了设计过程及步骤。 相似文献
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概述了毫米波技术在雷达探测及通信领域中的应用优势、使用场景以及未来的技术发展趋势,并着重对其技术实现面临的难点进行分析。同时,针对应用需求和技术特征的不同,介绍了满足各类应用的毫米波相控阵技术发展的不同技术路线,对其中涉及的架构、天线单元、器件和封装集成等主要关键技术进行了阐述,力图从总体上对其技术体制、应用情况和发展趋势进行科学分析和归纳,为毫米波相控阵天线技术的发展提供借鉴。 相似文献
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介绍了色散光纤在X波段雷达信号的光控相控阵中的应用——光纤延迟线,建立了光控相控阵雷达通信系统的模型,采用外调制的方法把微波雷达信号调制到光信号上,运用光学软件Optiwave来建立光控相控阵雷达的仿真系统。其结果可以为色散光纤在X波段光控相控阵雷达技术中的应用提供参考。 相似文献