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GLONASS Satellite Constellation

GLONASS is a radio-based satellite navigation system operated for the Russian government by the Russian Aerospace Defense Forces.

clc;
clear all;
fname = 'Glonass.txt';    % TLE file name
Earth3DPlot(1);
% Open the TLE file and read TLE elements
fid = fopen(fname, 'rb');
while ~feof(fid)
[ h, i, RAAN, e,omega,theta ] = TLE2OE( fid );
[Rv, alfa,delta ] = J2PropagR( h, i, RAAN, e,omega,theta) ;
scatter3(Rv(:,1),Rv(:,2),Rv(:,3),'.');
end
fclose(fid);
% Ground Track
EarthTopographicMap(2,820,420);
fid = fopen(fname, 'rb');
while ~feof(fid)
[ h, i, RAAN, e,omega,theta ] = TLE2OE( fid );
[Rv, alfa,delta ] = J2PropagR( h, i, RAAN, e,omega,theta) ;
scatter(alfa,delta,'.');
end
fclose(fid);
text(280,-80,'smallsats.org','Color',[1 1 1], 'VerticalAlignment','middle',...
'HorizontalAlignment','left','FontSize',14 );
 title('GLONASS Satellite Constellation');

Glonass Satellite Glonass_02

TLE Data Source. http://www.celestrak.com/ January 20, 2012

 

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GPS Satellite Constellation

The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites.

clc;
clear all;
fname = 'GPS.txt';    % TLE file name
Earth3DPlot(1);
% Open the TLE file and read TLE elements
fid = fopen(fname, 'rb');
while ~feof(fid)
[ h, i, RAAN, e,omega,theta ] = TLE2OE( fid );
[Rv, alfa,delta ] = J2PropagR( h, i, RAAN, e,omega,theta) ;
scatter3(Rv(:,1),Rv(:,2),Rv(:,3),'.');
end
fclose(fid);
% Ground Track
EarthTopographicMap(2,820,420);
fid = fopen(fname, 'rb');
while ~feof(fid)
[ h, i, RAAN, e,omega,theta ] = TLE2OE( fid );
[Rv, alfa,delta ] = J2PropagR( h, i, RAAN, e,omega,theta) ;
scatter(alfa,delta,'.');
end
fclose(fid);
text(280,-80,'smallsats.org','Color',[1 1 1], 'VerticalAlignment','middle',...
'HorizontalAlignment','left','FontSize',14 );
 title('GPS Satellite Constellation');

 

TLE Data Source. http://www.celestrak.com/ January 20, 2012

GPS BIIA-10 (PRN 32)    
1 20959U 90103A   13018.84945698  .00000048  00000-0  10000-3 0  8427
2 20959  54.4303 229.9128 0117665 335.2539  24.2342  2.00550891162214
GPS BIIA-14 (PRN 26)    
1 22014U 92039A   13019.14607454 -.00000071  00000-0  10000-3 0  6346
2 22014  56.1801 290.1218 0208290  69.5584 292.7075  2.00565875143955
GPS BIIA-15 (PRN 27)    
1 22108U 92058A   13018.75434799 -.00000089  00000-0  10000-3 0  5581
2 22108  56.2534 343.0502 0222435 303.9410  53.9615  2.00569608149127
GPS BIIA-21 (PRN 09)    
1 22700U 93042A   13018.74470584 -.00000088  00000-0  00000+0 0  8817
2 22700  56.4056 344.6226 0167916  93.9179 268.0033  2.00662093143282
GPS BIIA-22 (PRN 30)    
1 22779U 93054A   13018.51983509 -.00000069  00000-0  10000-3 0  5571
2 22779  55.1533  39.1818 0106140  92.6721 268.5873  2.00571221142039
GPS BIIA-23 (PRN 04)    
1 22877U 93068A   13018.41796082  .00000048  00000-0  10000-3 0  2373
2 22877  53.7295 164.7980 0102485  54.0859 306.8291  2.00556733140921
GPS BIIA-24 (PRN 06)    
1 23027U 94016A   13018.12046811 -.00000048  00000-0  10000-3 0  1955
2 23027  53.8565 101.4536 0076290 335.9203  23.7554  2.00561802138223
GPS BIIA-25 (PRN 03)    
1 23833U 96019A   13019.13913939 -.00000060  00000-0  10000-3 0  3935
2 23833  53.4736  96.9153 0157826  72.6851 289.0689  2.00564035123227
GPS BIIA-26 (PRN 10)    
1 23953U 96041A   13018.50101030  .00000050  00000-0  10000-3 0  8803
2 23953  54.1034 225.9914 0120793  44.6889 316.3194  2.00554012121004
GPS BIIR-2  (PRN 13)    
1 24876U 97035A   13019.00325574 -.00000072  00000-0  10000-3 0  3517
2 24876  56.3255 290.5219 0046517 120.2494 240.2582  2.00575732113546
GPS BIIA-28 (PRN 08)    
1 25030U 97067A   13019.63536166 -.00000082  00000-0  10000-3 0  2975
2 25030  57.1991 351.0337 0128256 195.9414 163.6595  2.00570836111451
GPS BIIR-3  (PRN 11)    
1 25933U 99055A   13019.25617045  .00000010  00000-0  10000-3 0  7874
2 25933  50.9146 148.4260 0136447  65.1740 296.2085  2.00561387 97361
GPS BIIR-4  (PRN 20)    
1 26360U 00025A   13016.87981762  .00000037  00000-0  10000-3 0  8761
2 26360  53.2134 222.1388 0052448  73.0764 287.5347  2.00576559 93011
GPS BIIR-5  (PRN 28)    
1 26407U 00040A   13019.21994987 -.00000062  00000-0  10000-3 0  8291
2 26407  56.2531  48.0068 0187923 257.4922 100.4450  2.00568287 91732
GPS BIIR-6  (PRN 14)    
1 26605U 00071A   13018.81568033 -.00000070  00000-0  10000-3 0  8445
2 26605  55.9113 288.9048 0069360 245.5421 113.7790  2.00561684 89323
GPS BIIR-7  (PRN 18)    
1 26690U 01004A   13018.69048158  .00000051  00000-0  10000-3 0  7237
2 26690  53.1752 225.1291 0138193 238.6253 120.0544  2.00553471 87732
GPS BIIR-8  (PRN 16)    
1 27663U 03005A   13019.05927186 -.00000062  00000-0  10000-3 0  1540
2 27663  56.3455  47.6478 0068033 359.8082   0.2361  2.00576901 73096
GPS BIIR-9  (PRN 21)    
1 27704U 03010A   13018.60667007  .00000047  00000-0  10000-3 0   377
2 27704  53.3697 165.0440 0198594 235.2103 122.8804  2.00553928 71879
GPS BIIR-10 (PRN 22)    
1 28129U 03058A   13018.73549856  .00000051  00000-0  10000-3 0  6108
2 28129  53.0451 225.2919 0063340 244.9211 114.4621  2.00564098 66589
GPS BIIR-11 (PRN 19)    
1 28190U 04009A   13019.17516771 -.00000046  00000-0  10000-3 0  6040
2 28190  55.1066 110.1249 0086959  14.6182 345.6476  2.00565996 64762
GPS BIIR-12 (PRN 23)    
1 28361U 04023A   13018.96324076 -.00000066  00000-0  10000-3 0  4238
2 28361  54.8505 285.6669 0081990 194.9306 164.8791  2.00552385 62846
GPS BIIR-13 (PRN 02)    
1 28474U 04045A   13018.96367060  .00000044  00000-0  10000-3 0  3107
2 28474  53.7850 163.8242 0119722 206.9062 152.4399  2.00573321 60202
GPS BIIRM-1 (PRN 17)    
1 28874U 05038A   13018.32217387 -.00000042  00000-0  10000-3 0  5695
2 28874  55.2624 107.1585 0081479 231.4916 127.7975  2.00551100 53614
GPS BIIRM-2 (PRN 31)    
1 29486U 06042A   13018.93123473 -.00000087  00000-0  10000-3 0  9604
2 29486  56.1978 346.2221 0082935 312.3064  46.9875  2.00549243 46326
GPS BIIRM-3 (PRN 12)    
1 29601U 06052A   13019.37101994 -.00000060  00000-0  10000-3 0  9912
2 29601  56.3013  46.5841 0041062   4.7967 355.2950  2.00567097 45242
GPS BIIRM-4 (PRN 15)    
1 32260U 07047A   13018.68384066 -.00000063  00000-0  00000+0 0  6980
2 32260  54.0003 283.4336 0051688   4.0264 356.0623  2.00561108 38627
GPS BIIRM-5 (PRN 29)    
1 32384U 07062A   13018.50083400 -.00000043  00000-0  10000-3 0  7369
2 32384  55.2952 107.6507 0020298 293.2614  66.5488  2.00557842 37341
GPS BIIRM-6 (PRN 07)    
1 32711U 08012A   13019.09384597 -.00000088  00000-0  10000-3 0  4945
2 32711  55.9093 345.9893 0061210 195.1431 164.6734  2.00559437 35567
GPS BIIRM-8 (PRN 05)    
1 35752U 09043A   13018.56516204  .00000053  00000-0  10000-3 0  2489
2 35752  54.3995 224.8319 0030098  13.9303 346.1949  2.00578808 25132
GPS BIIF-1  (PRN 25)    
1 36585U 10022A   13018.91284136 -.00000065  00000-0  10000-3 0   648
2 36585  55.6614  44.4964 0018446  28.7965 331.3534  2.00571492 19380
GPS BIIF-2  (PRN 01)    
1 37753U 11036A   13019.28928872  .00000046  00000-0  00000+0 0  5261
2 37753  55.0147 164.8917 0014277  20.5806 339.4484  2.00559276 11077
GPS BIIF-3  (PRN 24)    
1 38833U 12053A   13018.77758384 -.00000091  00000-0  00000+0 0   731
2 38833  54.9671 344.4909 0005362 333.1108  26.8609  2.00559339  2129

Satellite Ground Track, GPS BII-10

The Global Positioning System (GPS) is a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. In this example we implement algorithm to plot GPS ground track. Same algorithm could be used for any satellite.

clear all;
clc;
% Earth topographic map
figure(1);
xwidth = 820;
ywidth = 420;
hFig = figure(1);
 set(gcf,'PaperPositionMode','auto')
 set(hFig, 'Position', [100 100 xwidth ywidth])
hold on;
grid on;
axis([0 360 -90 90]);
load('topo.mat','topo','topomap1');
contour(0:359,-89:90,topo,[0 0],'b')
axis equal
box on
set(gca,'XLim',[0 360],'YLim',[-90 90], ...
    'XTick',[0 60 120 180 240 300 360], ...
    'Ytick',[-90 -60 -30 0 30 60 90]);
image([0 360],[-90 90],topo,'CDataMapping', 'scaled');
colormap(topomap1);
ylabel('Latitude [deg]');
xlabel('Longitude [deg]');
title('GPS BII-10 ground track');

R_e = 6378;        % Earth's radius
mu = 398600;       % Earth’s gravitational parameter [km^3/s^2]
J2 = 0.0010836;
we = 360*(1 + 1/365.25)/(3600*24);      % Earth's rotation [deg/s]
% GPS BII-10 Orbital Parametres
rp    =  19781  + R_e;       % [km] Perigee Radius
ra    =  20582  + R_e;       % [km] Apogee Radius
theta =  25;                 % [deg] True anomaly
RAAN  =  229.9128 ;          % [deg] Right ascension of the ascending node
i     =  54.4303 ;           % [deg] Inclination
omega =  335.2539  ;         % [deg] Argument of perigee

a = (ra+rp)/2;               % Semimajor axis
e = (ra -rp)/(ra+rp) ;       % Eccentricity
h = (mu*rp*(1 + e))^0.5;     % Angular momentum
T = 2*pi*a^1.5/mu^0.5;       % Period
dRAAN = -(1.5*mu^0.5*J2*R_e^2/((1-e^2)*a^3.5))*cosd(i)*180/pi;
domega = dRAAN*(2.5*sind(i)^2 - 2)/cosd(i);
% Initial state
[R0 V0] = Orbital2State( h, i, RAAN, e,omega,theta);
[ alfa0 ,delta0 ] = R2RA_Dec( R0 );
scatter(alfa0,delta0,'*k');

ind = 1;
eps = 1E-9;
dt = 20;        % time step [sec]
ti = 0;

while(ti <= 3*T);
    E = 2*atan(tand(theta/2)*((1-e)/(1+e))^0.5);
    M = E  - e*sin(E);
    t0 = M/(2*pi)*T;
    t = t0 + dt;
    M = 2*pi*t/T;
    E = keplerEq(M,e,eps);
    theta = 2*atan(tan(E/2)*((1+e)/(1-e))^0.5)*180/pi;
    RAAN  = RAAN  +  dRAAN*dt ;
    omega = omega + domega*dt;
    [R V] = Orbital2State( h, i, RAAN, e,omega,theta);
    % Considering Earth's rotation
    fi_earth = we*ti;
    Rot = [cosd(fi_earth), sind(fi_earth),0;...
        -sind(fi_earth),cosd(fi_earth),0;0,0,1];
    R = Rot*R;
    [ alfa(ind) ,delta(ind) ] = R2RA_Dec( R );
    ti = ti+dt;
    ind = ind + 1;
end
scatter(alfa,delta,'.r');
text(280,-80,'smallsats.org','Color',[1 1 1], 'VerticalAlignment','middle',...
	'HorizontalAlignment','left','FontSize',14 );

GPS Ground Track

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