卫星链路计算软件Satmaster帮助.docx

1、卫星链路计算软件Satmaster帮助上下行部分Site Name / LocationEnter the literal name of the site where the earth station is located up to a maximum of 40 characters (18 for country data files)Example input for country data files (18 characters maximum)LiverpoolExample input for all other forms (40 characters maximum)

2、Liverpool, Merseyside, England.基站名称输入基站所处位置的名称，最多40个字母。国家数据文件名举例（最多18个字母）：liverpool其他格式输入举例：Liverpool, Merseyside, England.Site LatitudeEnter the latitude of the site where the earth station is located. This must be entered in decimal degrees with the suffix N for north and S for South. No spaces ar

3、e allowed. Examples 53.33N or 27.89S Important Note:When entering data into country data files latitudes are required in degrees and minutes format as obtained from maps and atlases. In this case the fractional part represents the number of minutes and cannot exceed 59. In all other cases input in d

4、ecimal degrees are assumed. A conversion facility is provided under the calculate menu.基站纬度输入地面站的纬度。必须以小数后跟N或S表示。不能输入空格。比如53.33N或27.89S 注意事项当输入国家数据文件时纬度需要以地图上的度和分为单位。这种情况下，小数部分为分的表示，不能超过59。在其他情况下，都是以度来表示的。Caculate菜单中有一个转换工具。Site LongitudeEnter the longitude of the site where the earth station is loc

5、ated. This must be entered in decimal degrees with the suffix W for west and E for East. No spaces are allowed. Examples 3.00W or 29.79E Important Note:When entering data into country data files longitudes are required in degrees and minutes format as obtained from maps and atlases. In this case the

6、 fractional part represents the number of minutes and cannot exceed 59. In all other cases input in decimal degrees are assumed. A conversion facility is provided under the calculate menu.基站经度输入基站的经度。必须以小数后跟E或W表示。不能输入空格。比如3.00W 或29.79E 注意事项当输入国家数据文件时纬度需要以地图上的度和分为单位。这种情况下，小数部分为分的表示，不能超过59。在其他情况下，都是以度

7、来表示的。Caculate菜单中有一个转换工具。Altitude of SiteEnter the altitude of the earth station above sea level. This is primarily used in the calculation of rain attenuation and atmospheric absorption. The units are kilometres.5.0 km is the maximum altitude allowed. Enter zero if you will prefer a slightly pessimi

8、stic worst case link budget calculation.基站海拔输入基站的海拔。这主要是用来计算雨衰和大气吸收值，单位是千米。最大允许输入的海拔为5km。如果需要比较悲观链路预算可以输入0。Frequency频率Enter the centre frequency of the carrier in GHz. For the uplink, typical values are around 6GHz and 14GHz for C and Ku band respectively. For the downlink, values of 4GHz and 12GHz

9、are typical. The accepted range is 1GHz to 50GHz输入上行载波的中心频率，以Ghz为单位。典型C波段和Ku波段的值为6GHz和14GHz。下行的典型频率为4Ghz和12GHz。可输入的范围为1Ghz到50GHz。PolarizationThis is simply the polarization system adopted by the wanted satellite transponder and is either linear (ie vertical & horizontal) or circular. Enter the lette

10、r V for vertical polarization, H for horizontal polarization or C for circular polarization.极化这就是所需卫星转发器的极化方式，可以选线性（垂直和水平）或圆极化。输入“V”为垂直极化，“H”为水平极化，“C”为圆极化。Signal AvailabilityDepending on your system design requirements a choice of signal availability should be specified. For typical domestic satelli

11、te TV systems, a figure of 99.5% availability is normally sufficient. In fact most packaged fixed dish systems are designed around this figure. For SMATV you may require a higher figure of 99.9% and cable head even higher. The upper limit provided is 99.999% but this level of performance is rarely n

12、ecessary or even achievable. The parameter is used in calculating an appropriate fade margin based on the rain-rate statistics for the site. If you like to work with worst month statistics a conversion to average year signal availability is provided under the Calculate menu.With link budgets using u

13、plink power control systems a higher availability is often specified for the uplink than the downlink.信号可用度（年平均）根据你的系统设计需求，信号可用度应该是确定的。典型的国内TV系统，这个数到99.5%为宜。实际上大多集成的碟形天线系统按照这个数字设计。SMATV（卫星公共接收电视）需要高到99.9%的可用度，电视终端机则更高。最高可以设为99.999%但是这种程度的可用度不常用也不可行。这个数值经常用来计算合适的雨衰。如果你愿意通过“worstmonth最糟糕的一个月”数值转换为年平均信

14、号可用度，可以通过Calculatec菜单下的工具进行换算。如果链路使用上行功率控制系统，经常要设置一个较高的系统可用度。Antenna ApertureAntenna aperture is normally taken as the overall diameter of a parabolic dish, the major dimension if an offset focus antenna. Units are always metric (in metres) to conform to international engineering practice. The lower

15、 limit handled is 0.2 metres and the highest 50 metres.天线口径通常是抛物线天线的直径，偏馈天线的主要直径。单位都是米。最少为0.2米，最大为50米。Antenna EfficiencyAntenna efficiency is the amount of incident signal actually collected by the dish and feed, expressed as a percentage. Quality of construction, signal blockage by head units, and

16、method of feed affects this parameter. Most antennas have efficiencies of between 60% and 70%. If you do not know the efficiency of the antenna then enter 60% as a worst case value.With link budget and dual feed forms, the value entered may be prefixed with a + character so the value will be interpr

17、eted as a gain, in dBi, rather than efficiency.天线效率天线效率就是入射信号呗反射面和馈源收集到得数量，表示为一个百分比。建设施工质量，前馈部分的遮挡还有馈源材料会影响这项参数。多数天线的效率在60-70%之间。如果你不知道则输入60%作为最悲观估计在链路预算和双馈形式中，这个值必须加一个“+”前缀以便程序将其解读为增益，以dBi为单位，而不是天线效率。Coupling lossThis parameter is the total loss due to the insertion of waveguide components and pola

18、rizers. Values are expected in dB and are typically in the order of 0.3dB. You should add all the insertion losses of waveguide components, such as OMTs and polarizers, that you intend to use.耦合衰减这个数值是波导原件、偏振器引起的一切衰减。单位是dB，典型值为0.3dB。你应该输入整体的波导元器件的衰减，如OMT和偏振器。Antenna misspointing lossThis parameter a

19、llows for the pointing loss between the ground station antenna and the satellite antenna. It is unlikely in practice that the antenna will be targeted exactly due to initial installation errors, factors such as the stability due to wind and the station keeping accuracy of the satellite. A large ante

20、nna, having a narrow beamwidth and being relatively unstable in wind inherit a disadvantage over a small one.A typical allowance for mispointing is 0.3 dB. This may need to be increased to 0.5dB for very large antennas particularly in windy areas.天线偏离损耗这个数值是对星不准引起的地面站和卫星间的损耗。实际中因为初始安装误差，很难将天线完全对准卫星，

21、如风稳和地面保持精度等因素。大型天线发射窄波束时会相对于小天线更加不稳定。典型值为0.3dB。大型天线处于多风地带的话可能需要加到0.5dB.LNB Noise Figure (LNB Noise Temperature)The default interpretation of this input parameter is Noise Figure. However, if you prefix the input value with a + character it will be automatically interpreted as a Noise Temperature ins

22、tead.It is conventional to quote the noise figure of an LNB in dB for Ku and Ka bands and the equivalent noise temperature in Kelvin for S and C bands. It is usually more difficult and expensive to achieve low noise figures the higher the frequency. For Ku-band low cost LNBs are in the range 0.8dB t

23、o 1.0dB or 30K for C band.Note: We use the term LNB in the generic sense here, LNA, LNC etc is equally valid.LNB噪声默认的解读法是读为噪声因数，但如果在数值前加上“+”号则程序将其读为噪声温度。通常使用噪声因数表示Ku和Ka波段的LNB噪声，噪声温度表示。频率越高，通常来讲就越难以达到很低的噪声。比如Ku波段比较便宜的LNB噪声都是在0.8-1.0dB，C波段的通常为30K。Antenna noise temperatureA value for the antenna noise

24、temperature is often quoted in manufacturers specifications. The total noise temperature of the antenna depends mainly on the following factors:1) Sky Noise The total antenna noise, Tant = Tsky+Tgnd. The sky noise, Tsky, consists of two main components, absorption and the background big bang radiati

25、on (2.7K). Since the atmosphere is an absorbing medium it must be a noise source so sky noise increases with decreasing elevation due to the longer path through the atmosphere.2) Ground Noise The dominant contribution to antenna noise at low elevations is ground noise pick up through side lobes. Noi

26、se temperature increases as the elevation angle decreases since the antenna will pick up more ground noise due to side lobes intercepting the ground (diffraction effects at the antenna rim). This may be reduced by various methods of feed illumination and the dish design itself. A deep dish picks up

27、less ground noise at lower elevations than do shallow ones also prime focus mounted head units will add to noise since it is seen at the same temperature as the Earth. Estimating Antenna Noise TemperatureSince antenna noise temperature has so many variable factors, an estimate is perhaps the best we

28、 can hope for. In the absence of a specific manufacturer supplied figure, a reasonable estimate may be obtained by selecting Calculate|Estimate Antenna Noise Temperature from the menu.天线噪声温度天线的噪声温度通常标注在厂家的说明书中。天线的总噪声主要受以下几个方面影响：1） 天电噪声。天线的总噪声=天电噪声+地电噪声。天天电噪声，Tsky，包含两部分，空气吸收和大爆炸背景辐射。因为大气是一种（电磁波）吸收媒介所

29、以肯定会有噪声。所以海拔降低大气噪声就会增加，因为在电磁波在大气中传播的更远。2） 大地噪声。在低仰角的情况下对天线噪声影响最大的是旁瓣吸收的大地噪声。天线仰角降低，大地噪声就升高（天线的衍射效果）。它有可能通过馈源和反射面的特殊设计而减小。比较凹的天线反射面会减少大地噪声，而天线头部分也会增加噪声，因为它也可以看作和大地有一样的噪声。估算天线噪声温度因为天线噪声温度受很多因素影响，我们只好算出一个估计值。如果没有厂家提供的参数，使用Calculate-Estimate Antenna Noise Temperature进行计算。Adjacent Channel Interference C/

30、ACI相邻信道干扰Enter a value for the carrier to adjacent-carrier interference noise ratio C/ACI in dB. This parameter specifies the expected interference level with respect to the wanted carrier. A typical value to enter for either uplink or downlink is between 24 and 30dB. Some link programs do not use t

31、his parameter so if you wish to void it enter 60dB or more. Note that the higher this value is in dB, the lower the interference. 输入一个相邻信道干扰噪声C/ACI，以dB为单位。这个参数指定一个所需载波的干扰程度。上行和下行的典型值在24-30dB之间。很多工程不需要这些参数，如果不希望考虑它，输入60dB以上的值。注意这个值越高表示干扰越小。Adjacent Satellite Interference C/ASI相邻卫星干扰Enter a value for

32、the carrier to adjacent satellite interference noise ratio due to interfering signals to/from adjacent satellites in dB. This parameter specifies the expected interference noise with respect to the wanted carrier.A typical value to enter here for either uplink or downlink is between 18 and 30dB. Note that the higher this value is in dB, the lower the interference.输入一个相邻卫星干扰噪声C/ASI，以dB为单位。这个参数指定一个所需载波的干扰程度。上行和下行的典型值在18-30dB之间。注意这个值越高表示干扰越小。Cross Polarization Interference C/