easy10.m

非常全的GPS（全球定位系统）的Matlab源代码。

% EASY10 plots ionospheric delay from phase observations.
%        The present code does not handle
%   	 1. cycle slips, and
%	     2. outliers.

%Kai Borre 27-07-2002
%Copyright (c) by Kai Borre
%$Revision: 1.0 $  $Date: 2002/07/27  $

% Initial computations of constants
v_light = 299792458;	     % vacuum speed of light m/s
f1 = 154*10.23E6;		     % L1 frequency Hz
f2 = 120*10.23E6;			 % L2 frequency Hz
lambda1 = v_light/f1;	     % wavelength on L1:  .19029367  m
lambda2 = v_light/f2;	     % wavelength on L2:  .244210213 m

% We identify the observation file and open it
ofile = 'kofi1.01o'; 
fid = fopen(ofile,'rt');
[Obs_types, ant_delta, ifound_types, eof1] = anheader(ofile);
NoObs_types = size(Obs_types,2)/2;
obsstr(1,1:2) = 'P1'; % P1
obsstr(2,1:2) = 'P2'; % P2
obsstr(3,1:2) = 'L1'; % Phi1
obsstr(4,1:2) = 'L2'; % Phi2
match = zeros(1,4);
for t = 1:4
    for ii = 1:NoObs_types
        mat = strmatch(obsstr(t,1:2),Obs_types(1,2*ii-1:2*ii),'exact');
        if isempty(mat) == 0, match(1,t) = ii; end
    end
end
Oc = match; 
qend = 300;
phase_diff = zeros(32,qend)*inf;
disp(' ')
disp('Please wait for creation of plot!')
for q = 1:qend
    [time, dt, sats, eof] = fepoch_0(fid);
    NoSv = size(sats,1);
    obsm = grabdata(fid, NoSv, NoObs_types);
    obs = obsm(:,Oc); % P1 P2 Phi1 Phi2
    for t = 1:NoSv
        Phi1 = obs(t,3)*lambda1; 
        Phi2 = obs(t,4)*lambda2; 
        sat = sats(t);
        phase_diff(sat,q) = Phi1-Phi2;
    end
end; 
pd = phase_diff-phase_diff(:,1)*ones(1,qend);
prn = find(~isnan(pd(:,1)));
% We must delete rows with NaN's in order to cycle correctly through the colours
pd(isnan(pd(:,1:qend))) = []; 
pd = reshape(pd,length(prn),qend);
pd = pd/(1-(f1/f2)^2);

[m,n] = size(pd);
figure(1);
plot_handles = plot(1:n,1000*pd(1,:)','-',...
                    1:n,1000*pd(2,:)','--',...
                    1:n,1000*pd(3,:)','-.',...
                    1:n,1000*pd(4,:)',':',...
                    1:n,1000*pd(5,:)','.',...
                    1:n,1000*pd(6,:)','o',...
                    1:n,1000*pd(7,:)','*');
set(gca,'fontsize',16)
set(plot_handles,'linewidth',1,'markersize',1)
legend(eval('num2str(prn)'),2)
title('Ionospheric Delay From {\itL}_1 and {\itL}_2 Phases')
ylabel('Delay [mm]')
xlabel('Epochs [1 s interval]')
legend

print -deps easy10
%%%%%%%%%%%%%%%%%%%%%% end easy10.m  %%%%%%%%%%%%%%%%%%%