卫星通信实验报告1

南京信息工程大学卫星通信实验报告学院电子与信息工程学院专业通信工程年级2011级班级1班学号姓名实验一 卫星与轨道2一、实验原理2二、实验器材2三、实验内容2四、实验过程2实验二 QPSK 调制解调13一、实验原理13二、实验器材13三、实验内容13四、实验过程13五、总结14实验三GMSK调制15一、实验原理15二、实验器材 15三、实验内容 15四、实验过程 15五、总结 1 7实验一 卫星与轨道一、实验原理1、卫星只要获得这一水平方向的速度后，不需要再加动力就可以环绕地球1飞行。这时卫 星的飞行轨迹叫卫星轨道。卫星轨道参数是用来描述在太空中卫星运行的位置、形状和取向 的各种参数。同义词： 卫星轨道根数。(1)轨道平面的倾角i:赤道平面与卫星轨道平面间的夹角，具体计算是在卫星轨道升段时由(3) 轨道的偏心率e：焦距与轨道半长轴之比。(4) 升节点位置Q指从春分点到地心的连线与从升节点到地心的连线之间的夹角。(5) 近地点幅角« :指从升节点到地心的连线与从卫星近地点到地心的连线之间的夹角。从 升节点顺轨道运行方向度量，00 <« < 900。(6) 卫星初始时刻的位置W + V :是卫星在初始时刻到到地心的连线与升节点到地心的连线之 间的张角。其中v是初始时刻卫星在轨道内的幅角，从升节点位置开始计算。2、利用MATLAB可以把卫星的轨道参数直观的表现出来二、实验器材电脑、 MATLAB 软件等。三、实验内容用 MATLAB 仿真卫星轨道四、实验过程1 、 代码:function = orbits(action);% This function plots an Earth orbit based on% the following orbtial elements:% perigee = altitude at perigee (miles)% apogee = altitude at apogee (miles)% i = inclination of orbital plane to equatorial plane (degrees)% Omega = argument of ascending node (degrees)% omega = argument of periapsis (degrees)% Written with Matlab 5.3 by:% Michael Hanchak (mhanchak AT yahoo DOT com)% Dayton, Ohio% August 9, 2001% Reference Text:% Fundamentals of Astrodynamics% Published by Dover Press, 1971% Users of this function assume all risk in using the calculations% contained within. This function is not to be distributed without % the author's full consent.% For best results, requires "coast.mat" and "topo.mat"% standard switchyard programming logicif nargin = 0;action = 'build'end% Earth radius (miles)rad = 6378136/1000/1.6;colors = .6 .7 .8; colors2 = 'k'switch action% build GUIcase 'build'strings = 'w','W','i','Apogee','Perigee'tags = 'o','O','i','alt_a','alt_p' values = '45','45','30','345','115'strings2 = 'Plot Orbit','Clear Orbits','Center Earth',.'Zoom All','Flyby','Help','Toggle Earth','Quit' callbacks = 'orbits(''plot'')','orbits(''clear'')',.'camva(15);view(120,30);camlookat(findobj(''tag'',''earth'');' ,. 'camva(15);camlookat','orbits(''flyby'')','help orbits',. 'orbits(''earth'')','close(gcf)'if isempty(findobj('tag','orbits')www = figure'tag','orbits');elsewww = findobj'tag','orbits');figure(www);clfendset(www 'position',25 75 600 500'color',colors2);for kk = 1:length(strings),ppp = uicontrol'Units','pixels','Position',2 (20*(kk-1)+16) 50 20,.'String',stringskk,'style','text','backgroundcolor',colors2,.'foregroundcolor','w','fontsize',9); uicontrol'Units','pixels','Position',55 (20*(kk-1)+16) 5020,.'tag',tagskk,'style','edit','string',valueskk,'backgroundcolor', 1 1 1);if kk <=2 set(ppp'fontname','symbol','fontsize',12);endendfor kk =1:length(strings2), uicontrol'Units','pixels','Position',10 (25*(kk-1)+150) 70 22,.'string',strings2kk,'callback',callbackskk,'backgroundcolor',colo rs);end uicontrol('Units','pixels','Position',10 370 100 80,.'string','Left click and drag Earth for dynamic viewing.' ,.' Right click for zooming. Double-Click to center. ',.'style','text','backgroundcolor',colors2,'fontsize',8,. 'HorizontalAlignment','left','foregroundcolor','w');axes 'position',.2 .05 .75 .9,'units','normalized')axis equalaxis offaxis vis3dhold on% Plot reference frame axesh1 = plot(0 rad+500,0 0,'r-');h2 = plot(0 0,0 rad+500,'g-');h3 = plot3(0 0,0 0,0 rad+500,'color',0 0 .8);set(h1 h2 h3,'linewidth',4);view(120,30); camva(15);rot3d; data.simple = 1; data.handles = ;data.earthhandle = ;set(gcf 'userdata',data);orbits('earth') % call routine to draw earth camlookat(findobj('tag','earth');case 'earth'% determine level of graphicsdata = get(gcf,'userdata');simple = data.simple; delete(data.earthhandle); data.earthhandle = ;% Plot the earth (texture map or simple)if simple = 0 & isempty(which('topo.mat')X,Y,Z = sphere(50);loadtopo topo = topo(:,181:360) topo(:,1:180);mat.dull.AmbientStrength = 0.4; mat.dull.DiffuseStrength = .6; mat.dull.SpecularColorReflectance = .5; mat.dull.backfacelighting = 'reverselit' mat.dull.SpecularExponent = 20; mat.dull.SpecularStrength = .8;data.earthhandle(1) = surface(rad*X,rad*Y,rad*Z, . mat.dull,.'FaceColor','texturemap',. 'EdgeColor','none',.'FaceLighting','phong',. 'Cdata',topo,'tag','earth');colormap(topomap1) data.earthhandle(2) = light 'position',rad*10 10 10);%light('position',rad*-10 -10 -10, 'color', .6 .2 .2); %set(gcf,'renderer','opengl');data.simple = 1;else.9,'edge0X,Y,Z = sphere(24); data.earthhandle(1) = mesh(rad*X,rad*Y,rad*Z);%set(data.earthhandle,'tag','earth','facecolor',.6 .7 color',1 1 1);set(data.earthhandle(1)'tag','earth','facecolor',0 1,'edgecolor',.3 .3 1);if isempty(which('coast.mat')loadcoastncst = ncst *pi/180;all =zeros(length(ncst),3);for j = 1:length(ncst)theta = ncst(j,1);phi = ncst(j,2);all(j,:) = cos(theta)*cos(phi .sin(theta)*cos(ph .-sin(phi);enddata.earthhandle(2) = plot3(rad*all(:,1),rad*all(:,2),-rad*all(:,3);set(data.earthhandle(2)'color',0 .9 0);end data.simple = 0;endset(gcf 'userdata',data);% plot orbitscase 'plot' deg2rad = pi/180;data = get(gcf,'userdata'); handles = data.handles;% get orbital elements from GUI alt_p = str2num(get(findobj('tag','alt_p'),'string'); alt_a = str2num(get(findobj('tag','alt_a'),'string'); inc = str2num(get(findobj('tag','i'),'string');Omega = str2num(get(findobj('tag','O'),'string'); omega = str2num(get(findobj('tag','o'),'string');% check for correctness of input data if alt_p > alt_aerror1 = errordlg'Perigee must be smaller than apogee' ); waitfor(error1);else% Orbital elementsa = (alt_p + alt_a + 2*rad)/2;c = a - alt_p - rad;e = c/a;p = a*(1- e八2);th = linspace(0,2*pi,200);r = p./(1 + e*cos(th);xx = r.*cos(th);yy = r.*sin(th);Omega = Omega*deg2rad;inc = inc*deg2rad;omega = omega*deg2rad;% Coordinate TransformationsZZ = cos(Omega) -sin(Omega) 0; sin(Omega) cos(Omega) 0;0 0 1;XX = 1 0 0;0 cos(inc) -sin(inc);0 sin(inc) cos(inc);ZZ2 = cos(omega) -sin(omega) 0; sin(omega) cos(omega) 0;0 0 1;% actual plotvec = ZZ*XX*ZZ2*xx;yy;zeros(1,length(xx); h1 = plot3(vec(1,:),vec(2,:),vec(3,:); set(h1'linewidth',1,'color',1 1 1);% line of ascending nodevec1 = ZZ*rad+600;0;0;h2 = plot(0 vec1(1),0 vec1(2)'r-');% line of periapsisvec2 = ZZ*XX*ZZ2*rad+600;0;0;h3 = plot3(0 vec2(1),0 vec2(2),0 vec2(3)'color',.1 1 0);% line of inclinationvec3 = ZZ*XX*0;0;rad+600;h4 = plot3(0 vec3(1),0 vec3(2),0 vec3(3) . 'color',0 0 .8);set(h2 h3 h4'linewidth',2);data.handles = data.handles h1 h2 h3 h4; set(gcf'userdata',data);%camlookat;endcase 'clear'data = get(gcf,'userdata'); handles = data.handles;for rr = 1:length(handles)if ishandle(handles(rr) delete(handles(rr);endend data.handles = ; set(gcf 'userdata',data);case 'flyby'camlookat(findobj('tag','earth'); camva(15);camup(0 0 1);for x = -300000:1000:60000 campos(x,30000,30000) drawnowaxesend% here are the recursive callbacks for the rotation of the case 'rot'rot3d 'rot');case 'down'rot3d 'down');case 'up'rot3d 'up');case 'zoom'rot3d 'zoom');end% this function below allows for dynamics "click and drag"% rotation of the plot.function rot3d(huh)if nargin<1set(gcf 'WindowButtonDownFcn','orbits(''down'')'); set(gcf'WindowButtonUpFcn','orbits(''up'')');set(gcf 'WindowButtonMotionFcn','');elseswitch huhcase 'down'if strcmp(get(gcf,'SelectionType'),'normal') set(gcf'WindowButtonMotionFcn','orbits(''rot'')');elseif strcmp(get(gcf,'SelectionType'),'alt') set(gcf'WindowButtonMotionFcn','orbits(''zoom'')');elseif strcmp(get(gcf,'SelectionType'),'open') %center point temp1 = get(gca'currentpoint');temp1 = (temp1(1,:) + temp1(2,:)/2;% average points %newvec = temp1 - campos%oldvec = camtarget-campos%dir = cross(oldvec,newvec)%ang = atan2(norm(dir),dot(oldvec,newvec)+2 %campan(-ang,0,'data',dir);camtarget(temp1);endrdata.oldpt = get(0'PointerLocation'); set(gca'userdata',rdata);case 'up' set(gcf'WindowButtonMotionFcn','');case 'rot'rdata = get(gca'userdata');oldpt = rdata.oldpt;newpt = get(0'PointerLocation');dx = (newpt(1) - oldpt(1)*.5;dy = (newpt(2) - oldpt(2)*.5;%direction = 0 0 1;%coordsys = 'camera'%pos = get(gca,'cameraposition' );%targ = get(gca,'cameratarget' );%dar = get(gca,'dataaspectratio');%up = get(gca,'cameraupvector' );%newPos newUp =camrotate(pos,targ,dar,up,-dx,-dy,coordsys,direction);%set(gca,'cameraposition', newPos, 'cameraupvector', newUp); camorbit(gca,-dx,-dy'camera');rdata.oldpt = newpt;set(gca'userdata',rdata);case 'zoom'rdata = get(gca'userdata');oldpt = rdata.oldpt;newpt = get(0'PointerLocation');dy = (newpt(2) - oldpt(2)/abs(oldpt(2); camzoom(gca,1+dy)rdata.oldpt = newpt;set(gca'userdata',rdata)endendLeft click and drag Earth ford/namic viewing. Right click for ZDDming. Double-Click to nftntfl-rPerigeeApogeeQuit-oggle EarthHelpFlybyZoom AllCenter EarthClear OrbitsPlot Orbit3GFigure 1di回anFile Edit View n sert Tools Desktop Window 旦 edp2、 结果图：Perigee近地点Apogee远地点i轨道平面的倾角。升节点位置®近地点幅角 改变i、O的值可以得到不同的卫星轨道Center EarthClear OrbitsPlot OrbitPerigeeLeft click and drag Earth for dynamic viewing. Right click for ZDDming.Dnuble-Click to rftntftrToggle EarthZoom AllApogee五、总结卫星轨道参数是用来描述在太空中卫星运行的位置、形状和取向的各种参数，可以在 MATLAB图中形象的表示出来。实验二 QPSK 调制解调一、实验原理四相相移键控信号简称“QPSK”它分为绝对相移和相对相移两种。由于绝对相移方式存在 相位模糊问题，所以在实际中主要采用相对移相方式DQPSK。它具有一系列独特的优点， 目前已经广泛应用于无线通信中，成为现代通信中一种十分重要的调制解调方式。在数字信号的调制方式中QPSK四相移键控是目前最常用的一种卫星数字信号调制方式。QPSK信号6炮任通抽樺雄敬1实验图：Conversion binaire/decimale et integration de I'information dans la phase une porteuse cosinusoidale电脑、MATLAB三、实验内容fin.Clock二、实验器材用MATLAB仿真四、实验过程ti'2(-Ifceilfu)YDataFcn2+Generation desbits en serieXY GraphlDiagramme de phaseS1O6 sFS9kamal.koubaa结果图：载波频率 50/(2*pi)五、总结在数字信号的调制方式中 QPSK 四相移键控是最常用的一种卫星数字信号调制方式,它具有 较高的频谱利用率、较强的抗干扰性、在电路上实现也较为简单。偏移四相相移键控信号简 称“O-QPSK”。全称为offset QPSK,也就是相对移相方式OQPSK。它具有一系列独特的优 点，已经广泛应用于无线通信中，成为现代通信中一种十分重要的调制解调方式。实验三GMSK调制一、实验原理高斯滤波最小频移键控（GaussianFilteredMinimumShiftKeying）,这是GSM系统采用的调制 方式。数字调制解调技术是数字蜂窝移动通信系统空中接口的重要组成部分。GMSK调制 是在MSK （最小频移键控）调制器之前插入高斯低通预调制滤波器这样一种调制方式。 GMSK提高了数字移动通信的频谱利用率和通信质量。翹* 耳啊淋用IUmsk图1 GMSK调制双极性码元通过高斯滤波器产生拖尾现象，所以相邻脉冲之间有重叠。对应某一码元,GMSK 信号的频偏不仅和该码元有关，而且和相邻码元有关。也就是说在不同的码流图案下，相同 码元（比如同为“+1”或“-1”）的频偏是不同的。相邻码元之间的相互影响程度和高斯滤波器的参数有关，也就是说和高斯滤波器的 3dB 带 宽B有关。BT值越小，GMSK信号功率频谱密度的高额分量衰减越快。主瓣越小，信号所 占用的频带越窄，带外能量的辐射越小，邻道干扰也越小。调制原理图：解调原理图：2iT(2i+2)TJ*数拥(2j I 1) 7；二、 实验器材I砒相卩解调原理图电脑、MATLAB软件等三、实验内容用MATLAB仿真GMSK四、实验过程实验图：lmk_kml结果图：S2Time offset: 0