“动中通”卫星通信设备软件设计

介绍了"动中通"高精确度卫星跟踪技术和天线的控制技术,为了保证系统在移动平台上完成卫星通信,采用了开环跟踪与双闭环校正的控制算法。通过监控处理完成跟踪算法任务处理,软件系统采用vxWorks实时操作系统为平台,保证了跟踪的高实时性;显控处理软件采用图形图标控件(NI控件)技术,实时显示系统的状态和故障信息;伺服处理软件完成天线角度的控制,保证实时响应。实现了"动中通"卫星通信设备在运动平台上的高可靠通信,满足"动中通"卫星通信设备跟踪锁定和通信的要求。     

基于局域预测的动载天线伺服控制策略研究

针对中小涌浪的扰动,研究了一种基于少量数据的局域预测方法,应用于海面小型漂浮式动载天线跟踪卫星的方位和俯仰伺服控制中.以天线系统的少量位置数据为基础,采用局域预测算法预测天线的位置,计算天线指向将偏离卫星的偏差值,进行天线指向偏离卫星的补偿控制;基于天线位置间相关性,研究了局域预测算法并进行仿真验证;根据天线系统的组成设计了天线方位伺服控制器,并通过matlab仿真和半实物仿真验证了局域预测伺服控制策略的可行性、可靠性和鲁棒性.     

一种卫星动中通阴影和波束指向偏差估计方法

当目标卫星被遮挡,或天线波束指向偏差较大时,卫星通信质量会变差,甚至导致卫星通信中断。针对卫星动中通阴影和天线波束指向偏差的问题,建立了一种综合考虑地理环境和波束指向偏差的接收信号功率模型,提出了一种基于接收信号强度特征参数的阴影判断和天线波束指向偏差估计方法,方法充分利用了卫星动中通信道特性,适用于接收信号的快变化和慢变化两种情况。当出现个别较大指向偏差值时,模型能够有效降低误差影响。最后给出了实验仿真结果,验证了该方法的有效性。     

天宇通信让动中通"隐形"

6月27日,天宇通信在上海正式推出了其采用美国Stealth Ray隐形天线子系统的隐形"动中通"应急卫星通信系统。据了解,这种天线在国内的使用尚属首创,而天宇通信作为该天线技术的中国惟一经销商,也是最早推出隐形"动中通"应急卫星通信系统的厂商。有业内专家认为,这种隐形天线技术在卫星通信领域可谓是一种革命性的技术,是隐形"动中通"应急卫星通信系统的核心技术。     

动中通多子阵天线自适应PID滑模稳定控制

动中通在载体运动中进行卫星通信时,天线受到各类扰动的影响而不能准确对准卫星,降低了通信质量。为了解决此问题,设计了一种自适应滑模天线姿态稳定控制器。首先建立了动中通天线系统的动力学模型;基于此模型,采用PID滑模面设计了天线的滑模姿态控制器;通过对扰动的自适应估计,在扰动上界未知情况下获得了平滑的滑模控制输入;将PID方法引入控制器设计,提高了系统的动态响应速度。仿真结果表明,所设计控制器具有良好的动态响应特性和控制精度,且控制电压输出无抖振。     

动中通地面站卫星天线伺服控制系统

实现动中通卫星通信的天伺系统有多种,常用的有抛物面天伺系统和相控阵天伺系统两种型式。重点讨论采用具有零值自跟踪和以捷联惯导作数字引导跟踪的抛物面天线的动中通卫星通信设备的工作原理,并对该型式的动中通卫星通信设备的伺服跟踪系统的电气性能和价格进行了比较。还对动中通卫星通信设备的各种功能也进行了详细论述。这些都可作为用户选用动中通设备的一个参考。     

一种高性价比船载卫星通信天线系统的设计与应用

根据目前移动卫星通信站应用的实际情况,结合市场上主要相关移动卫星通信站产品的设计原理及技术原理,探讨船载"动中通"卫星通信天线的设计原理及相关技术应用,给出多种设计方案,并进行系统性比较,旨在寻找一种最优性价比的船载"动中通"卫星通信天线系统的设计方法,提供低成本"动中通"卫星通信天线系统的构建思路,使移动卫星站的建设和应用范围更广阔,更适合于民用及低成本应用领域,解决广阔海域范围内的多媒体通信问题,有效延伸飞速发展的信息高速公路。     

基于C8051F130的动中通天线控制系统

结合实际研究项目介绍了一种基于SoC思想新型单片机C8051F130的动中通卫星通信天线控制系统,采用先进的闭环反馈控制策略加圆锥扫描自动跟踪机制,提高了系统跟踪精度,能够使天线快速稳定地对准卫星,实现运动中稳定地通信。同时给出了天线控制系统软件的功能模块、流程图以及实验结果。测试结果表明基于C8051F130的动中通天线控制系统结构简单、性能达到了设计指标,且具有成本低的特点。     

动中通卫星通信系统中的天线问题

本文简述了动中通卫星通信系统的应用场合,使用特点,说明了动中通卫星通信天线需要满足的一些规定,列举了三种不同类型的典型动中通天线,并分别介绍了它们的主要性能,区别和优缺点。     

动中通卫星通信天线

为实现动中通卫星通信 ,采用反射式宽带 TE2 1模跟踪器、双通道旋转关节及极化程序跟踪技术 ,研制出适用于动中通的高性能卫星通信天线 ,填补了国内空白。     

舰载测量雷达船摇稳定回路设计

速率陀螺敏感于天线空间运动角速率,故可将陀螺感受的角速率信息作为反馈信息构成负反馈回路,通过加入船摇扰动前馈补偿环节,实现稳定回路的复合控制。再通过误差校正后将船摇补偿输出到功放,驱动天线方位及俯仰运动,达到隔离船摇扰动对天线指向影响的目的。设计已成功应用于舰载测量雷达的研制中,经对雷达性能测试,船摇隔离度达到50 dB。     

两轴稳定方式中牵联运动的补偿

扰动是三维的，稳定是两轴的，在速率陀螺稳定方式中，垂直于方位轴和俯仰轴的扰动速率分量，稳定回路无法直接稳定，而要靠直接或间接测出扰动速率分量加入到稳定回路进行补偿。本文仔细分析了牵联运动对跟踪的影响，推导出了直接或间接扰动速率补偿方程。     

Antenna control systems: from PI to H∞

This paper discusses the compensation of antenna-pointing errors following the analysis and retrofit of the NASA Deep Space Network antenna control systems. The desired high-frequency communications with spacecraft (at Ka-band) require improved pointing precision over lower-frequency communications (at X-band). The quality of the antenna drives (hardware), the control algorithm (software), and the physical structure of the antenna (in terms of thermal deformations, gravity distortions, encoder mounting, and wind gusts) all influence pointing precision, and create the challenging task of remaining within the required pointing-error budget. Three control algorithms-PI (proportional-and-integral), LQG (linear-quadratic-Gaussian), and H_∞-are discussed, and their basic properties, tracking precision, and limitations as applied to antenna tracking are addressed. The paper shows that the PI algorithm is simple and reliable, but its performance is limited. It also explains how significant improvements in tracking precision are achieved when implementing the LQG control algorithm or the H_∞ control algorithm. Still, pointing precision attributable to software modification is limited. It is pointed out that an additional increase of tracking precision requires concurrent improvements in the antenna drives     

深空站大天线抗风扰LQG最优控制器设计

针对深空大天线阵风扰动引起天线指向不准、接收信号抖动等问题,提出了基于最优控制策略的天线抗风扰LQG控制器设计方案。从控制对象建模、线性二次型最优控制和卡尔曼最优估计等方面详尽阐述了LQG最优控制器设计。借鉴国外DSN(深空网)相关工程经验与MATLAB工具对LQG控制器性能做了仿真分析。对LQG工程设计值得注意的问题进行了简要说明,目的旨在分析与解决相关工程技术问题,提高天线指向控制精度。     

高精度窄波束二次雷达指向精度补偿

相控阵天线的指向精度对雷达系统的精度有非常重要的影响。影响天线指向精度的因素很多,包括移相器量化单位误差、TR 单元间的物理结构、安装位置误差等。为了确保二次雷达的量测精度,天线的指向精度必须高于雷达系统的测向精度。本文制定出一种高效的指向误差补偿方案。该方案不仅可以大幅度减小指向误差,而且可以节约修正指向误差时间和人员的投入。     

Disturbance rejection control method for permanent magnet synchronous motor speed-regulation system

The speed-regulation problem for permanent magnet synchronous motor (PMSM) system is studied in this paper. To guarantee the disturbance rejection ability of the closed loop system, most of the existing advanced control methods develop disturbance rejection control laws only for speed loop. To further improve the disturbance rejection ability, a control scheme which employs disturbance rejection control laws for not only speed loop but also the q-axis current loop, is developed here. Considering the dynamics of q-axis current, the coupling between rotor speed and d-axis current as well as the back electromotive force are regarded as lumped disturbances for the q-axis current loop, which are estimated by introducing an extended state observer (ESO). Thus a composite control law consisting of proportional feedback and disturbance feedforward compensation is developed to control the q-axis current. Simulation and experiment comparisons are presented to verify the effectiveness of the proposed method.     

低频补偿TEM喇叭天线的仿真与测试

以超宽带窄脉冲辐射为应用背景,通过添加补偿回路并调整回路的大小,设计了一种具有低频补偿的超宽带TEM喇叭天线.利用FDTD方法对天线结构进行了仿真,分析了不同补偿回路大小时TEM喇叭天线的S11参数、相位特性、辐射带宽及前后向辐射场等参数,得到了在大于400 MHz频带范围内S11参数低于-10 dB的天线结构.制作天线原型,并进行了实际测试,频域S11参数测试结果与仿真结果基本吻合.通过对时域波形的分析可知,该天线具有较高的波形保真度.     

Control systems of the large millimeter telescope

This paper presents the analysis results (in terms of settling time, bandwidth, and servo error in wind disturbances) of four control systems designed for the Large Millimeter Telescope (LMT). The first system, called PP, consists of the proportional and integral (PI) controllers in the rate and position loops, and is widely used in the antenna and radio telescope industry. The analysis shows that the PP control system's performance is remarkably good when compared to similar control systems applied to typical antennas. This performance is achieved because the LMT structure is exceptionally rigid; however, it does not meet the stringent LMT pointing requirements. The second system, called PL, consists of the PI controller in the rate loop, and the linear-quadratic-Gaussian (LQG) controller in the position loop. This type of controller is implemented in the NASA Deep Space Network antennas, where pointing accuracy is twice that of the PP control system. The third system, called LP, consists of the LQG controller in the rate loop, and the proportional-integral-derivative (PID) controller in the position loop. This type of loop has not been yet implemented at known antennas or radio telescopes, but the analysis shows that its pointing accuracy is the ten times better than the PP control system. The fourth system, called LL, consists of the LQG controller in both the rate loop and the position loop. It is the best of the four, with accuracy 250 times better than the PP system. It is thus worth further investigation to identify implementation challenges for telescopes with high pointing requirements.     

基于Simulink的火炮伺服系统自抗扰控制仿真

为了解决火炮伺服系统存在负载变化大、冲击扰动力矩强等问题,将自抗扰控制技术应用到火炮伺服系统位置控制器中。该控制算法通过实时估计与补偿来弥补传统控制方法的不足。通过在Simulink软件平台搭建了ADRC的火炮伺服系统三环模型,仿真结果对比传统PID控制。对比结果表明,基于ADRC的系统超调小、响应速度较快、具有较强的鲁棒性。     

Closer spacing of geostationary satellites through adaptive nulling at the ground terminal

The results of a preliminary study suggest that interference to the downlink of one geostationary satellite from that of another satellite in the adjacent orbital slot can be substantially reduced by the addition of a simple adaptive nulling system to the ground terminal antenna. Alternatively, the nulling system allows the satellites to be spaced significantly closer together with no increase in interference. Significant improvement is obtained with simple open-loop antenna pointing. The improvement is greater, however, if the adaptive antenna automatically tracks the direction of the desired source. For a dish antenna with a single receiving feed horn, the extra hardware required to provide the adaptive capability consists of two more receiving feed horns, a variable weighting device for each of the feed lines (now three in number) and the adaptive control electronics. An example shows that the minimum spacing between one satellite and an interfering satellite, consistent with certain assumed operating requirements, could be reduced from the2.25degneeded for a simple single beam antenna to1.35deg, for the adaptive antenna using open loop pointing, to as little as0.7deg, for the adaptive antenna using automatic pointing. The adaptive hulling also provides essentially the same protection against downlink interference from the two other satellites occupying the slots on both sides of the satellite serving the terminal. The three degrees of freedom of the postulated nulling system, however, cannot cope with three or more nearby interfering satellites.