卫星地球站天线系统测试

本文通过湖北卫星地球站9米天线系统的验收测试，介绍了卫星地球站天线系统测试的原理和方法，并给出测试结果。     

地球站天线对准卫星角度快速调整

本文根据实践，总结经验，介绍了快速调整地球站天线对准卫星角度的方法，对新建地球站和转星接收有一定应用价值。     

卫星接收天线的调整和常见问题的处理

接收天线是地球站的核心设备之一。天线的调整、故障排除和干扰应对,是地球站工作基本功。     

湖北卫星地球站9 m备份天线的建设与电路连接设计

叙述了湖北广播电视卫星地球站9 m备份天线的建设过程,对天线的基础建设、安装和入网过程以及电路连接设计都进行了详细的介绍,各项指标在实测中都达到了要求.     

地球站天线极化夹角的调整

本文闸明了地球站天线产生极化夹角的原理;导出了计算极化夹角的公式;给出了全国各地具有代表性的一些地球站极化夹角值,供有关研制人员和操作人员调整地球站天线消除极化夹角影响之参考。     

论地球站非自跟踪对空通信天线的极化和方向图

文章指出非自跟踪地球站对空通信天线的极化和方向图应与空间飞行体信标天线相配合统筹考虑，才能获得满意的通信效果。文中着重研究并指出：在飞行体用铅垂振子作为信标天线时，地面天线应采用θ极化山字形方向图。该新观点必将推动人们研究创造具有这种性能的新天线。     

几种新颖的旋转对称双反射镜天线

本文介绍四种旋转对称双反射镜天线构成的基本原理及设计计算公式.有两种天线具有碟形波束,适用于微波多址通信的中央站.由于在水平面上具有完全均匀的辐射特性而在铅垂面上呈极锐波束的辐射特性,可以使中央站发出的电磁信号得到极充分的利用,因而是颇有吸引力的新天线.有两种天线具有所谓铅笔形锐波束,适用于卫星通信地球站或其他点对点的微波通信站,其中环焦天线在小孔径天线中更有明显的优越性.     

移动卫星通信系统的地球终端站天线

本文首先介绍移动卫星通信的工作频段，并概述各个频段天线的特点，然后详述Ｖ－Ｕ频段的和Ｌ频段的间或其它频段的天线特点和主要形式，以及对天然的性能要求；最后对于各个频段的各种地球终端站天线现状作一概述，并对它的发展作一展望。     

卫星通信地球站与卫星相对参数计算方法

在卫星通信中,为了保证地球站信号的接收与发射,需要对地球站与卫星间的多普勒频移、信号传输延时以及地球站天线指向等参数进行计算。针对卫星通信地球站在通信过程中卫星轨道位置外推与相对参数的计算问题,在卫星的运动方程的基础上,采用单步积分与多步积分相结合的数值积分法,根据卫星星历计算卫星轨道的外推数据分别给出了地球站与卫星间多普勒频移、信号传输延时以及地球站天线指向等参数的计算方法。并对该方法的计算误差进行了仿真分析,仿真结果表明该计算方法切实可行,适用于工程应用。     

关于多波束抛物环面天线α角的确定

本文利用最小二乘法导出了抛物环面天线α角的求解方程,并给出了抛物环面天线的生成轴与地球站当地坐标系的关系。     

卫星地球站天线屏蔽方法研究

近年来,卫星地球站电磁环境日益恶化,必须加强卫星电磁干扰防护。天线作为卫星地球站最重要的设备之一,在完成正常收发任务的同时,也是电磁干扰耦合的主要途径。因此,对卫星地球站天线进行屏蔽是卫星地球站电磁干扰防护的一种行之有效的方式。根据刃峰绕射损耗模型,研究了地球站天线屏蔽体的设置方法,分析了屏蔽体设置距离与屏蔽体高度之间的关系。并根据理论分析结果,建议在地球站天线周围设置金属网。     

卫星通信地球站系统驱动电动机的选择

卫星通信地球站天线驱动电动机的选择需从机械、电子和伺服控制等方面综合考虑,其难度较大且至关重要。具体分析各类卫星通信地球站天线选择驱动电动机的依据,对卫星通信地球站天线驱动电动机的选择有一定参考价值。     

天线增益频带特性确定的一种简单方法

介绍了用卫星源法测量卫星通信地球站天线的特点。简述了利用3dB和10dB波束宽度确定地球站天线增益的原理和方法。提出了利用外推法确定天线增益频段特性的一种简单方法。对波束宽度法测量增益的误差进行了分析和估算,其均方根误差±0.387dB。最后给出了某工程应用的C波段15m地球站天线增益测量结果,增益测量结果与理论计算结果吻合很好。     

圆口径地面站天线近区功率密度的计算

简述了圆口径地面站天线发射近区功率密度的计算方法。推导了圆口径均匀分布、锥削分布和高斯分布的圆口径天线近区功率密度的简化计算公式,并根据地面站天线旁瓣增益包络的要求,提出了一种快速估算地面站天线偏轴近区功率密度的简单方法。     

卫星通信地球站微波干扰计算与分析

总结了微波接力通信站对卫星通信地球站的同频干扰的计算步骤和方法.首先计算地球站的工作方位和仰角,分析地球站和微波站的相对位置关系；然后,在得到卫星站和微波站相互间的干扰鉴别角的基础上,分别计算两站在干扰方向的天线增益；最后,计算卫星站接收机输入端的干扰信号允许电平和实际的干扰信号电平,通过对比两者的关系,可以判断预选站...     

Offset Cassegrain Earth Station Antenna for the Japanese Domestic Satellite Communication System

Offset reflector antennas have advantages for communication systems because they are not severely subject to blocking. Difficulties mainly arising from structual asymmetries have inhibited the realization of an offset reflector antenna with a large aperture for commercial use. This paper describes the design of an offset Cassegrain earth station antenna for the Japanese domestic satellite communication system. Antenna measurements showed 76 and 69 percent aperture efficiencies at 20 and 30 GHz, respectively, less than -20 dBi wide angle directivity and an 18 K noise temperature in operating conditions. Performances are far superior to conventional axisymmetrical earth station antennas. The antenna was reassembled on a telephone office building after the measurements. The antenna gain was reconfirmed there, using the sun as a radio frequency source. Experiments show that the earth station antenna and a terrestrial antenna can be placed on the same building without serious interference.     

地球站最大EIRP的测量及误差分析

介绍了地球站系统测量中等效全向辐射功率的基本概念,阐述了利用场地法对地球站系统最大等效全向辐射功率测量的原理和方法,推导并给出了场地法测量地球站系统最大等效全向辐射功率的计算公式。给出了工程测量实例(L波段16 m地球站天线最大等效全向辐射功率值的测量),并对地球站等效全向辐射功率的测量误差进行了分析。实验结果表明,其均方根误差±0.30 dB。     

Degradation Analysis of User Terminal EIRP and G/T due to Station‐Keeping Variation of Stratospheric Platform

Wireless communication systems using airship have been proposed in worldwide. The airship will be located at the stratosphere about 20 ~ 23 km above the sea level. The position of airship will vary within the station keeping range with time due to the drag of the wind in the stratosphere. When the earth station antenna has a high gain without the tracking function, the antenna performance may be degraded by a small variation of the airship. This means that variation of airship location could result in serious degradation of the system performance. In this paper, degradation in earth station's Equivalent Isotropic Radiated Power (EIRP) and Gain to noise Temperature ratio (G/T) due to the stratospheric platform movements has been derived by calculating the deviation angle of the main beam directions between the earth station and the platform antenna. In this case, the antenna of the earth station has been assumed circular and/or patch array antennas.     

Satellite system measurements

This paper describes the measurement techniques employed to test the elements of a communications satellite system. Techniques for measuring the gain-to-noise-temperature ratio (G/T) of an earth station antenna are presented. The measurement of earth station polarization characteristics is discussed extensively in terms of the new requirement for frequency reuse on orthogonal polarizations. Methods for in-orbit measurement of spacecraft performance including antenna characteristics are included, as well as some typical experimental results.     

A probabilistic model to describe the interference produced by VSAT MF‐TDMA networks

This paper develops a mathematical model to describe the statistical behavior of the interference produced by VSAT/MF‐TDMA networks. The model is used to assess the interference produced by the uplinks of a VSAT/MF‐TDMA network into links of a network that uses a neighboring satellite. In the proposed model, analytical expressions were developed to account for the effects of variations in transmitting powers, antenna sizes, and transmitting antenna pointing errors. The earth station locations are modeled by a 2‐dimensional Poisson point process. The model is general enough to accommodate other types of point processes and can be applied to situations involving service areas containing multiple types of earth station geographical distribution. Numerical results obtained with the proposed model are compared with those based on the actual parameter values (eg, earth station locations, antenna sizes, and transmitting powers), which were provided by a Brazilian satellite operator.