plotsky.m

此功能包用于各种GPS坐标和时间的转换

function p_handle = plotsky(az,el,prn_pass,plot_title,spoke_label)

% p_handle = plotsky(az,el,prn,plot_title,spoke_label);
%
% Function to plot the trajectories on a polar sky (azimuth/elevation) plot
% for a single observer. Each arc generated by a satellite is colored and
% labeled with the prn number. This function will use the current figure
% if one is available. Otherwise, a figure will be created. Zoom 
% capability is added to the figure. See help on ZOOM for more information.
% Starting points are not labeled and end points are labeled 
% with 'x'. 
%
% Input:
%   az          - azimuth (-pi to 2*pi rad) (nx1)
%   el          - elevation (-pi/2 to pi/2 rad) (nx1)
%   prn_pass    - [satellite number, pass number], nx1 or nx2 (optional),
%                 pass numbers are computed by PASSDATA. 
%                 if not provided, a single line is drawn
%   plot_title  - title of plot (1xm string) (optional) default = 'Sky Plot'
%   spoke_label - labels for the North, East, South,and West spokes of the 
%                 plot. (4xn string) (optional).  
%                 default = str2mat('N','E','S','W')
% Output:
%   p_handle    - graphics handle to the figure
%
% See also PLOTPASS

% Written by: Jimmy LaMance 11/7/96
% Modified by: Maria Evans 5/5/98
% Copyright (c) 1998 by Constell, Inc.

% functions called: ERR_CHK, PLOTPOLR

%%%%% BEGIN VARIABLE CHECKING CODE %%%%%
% declare the global debug variable
global DEBUG_MODE

% Initialize the output variables
p_handle=[];

% Check the number of input arguments and issues a message if invalid
msg = nargchk(2,5,nargin);
if ~isempty(msg)
  fprintf('%s  See help on PLOTSKY for details.\n',msg);
  fprintf('Returning with empty outputs.\n\n');
  return
end

% check that the size of the prn_pass input is valid, if provided
if nargin < 3,
  prn_pass = zeros(size(plot_data,1),2);
end % if nargin < 3
% Check to make sure the title string is a valid size
if nargin < 4,
  plot_title = ['Sky Plot'];
end % if nargin == 4
if nargin < 5
  spoke_label = str2mat('N','E','S','W');
end % if nargin >= 5

% Get the current Matlab version
matlab_version = version;
matlab_version = str2num(matlab_version(1));

% If the Matlab version is 5.x and the DEBUG_MODE flag is not set
% then set up the error checking structure and call the error routine.
if matlab_version >= 5.0                        
  estruct.func_name = 'PLOTSKY';

  % Develop the error checking structure with required dimension, matching
  % dimension flags, and input dimensions.
  estruct.variable(1).name = 'az';
  estruct.variable(1).req_dim = [901 1];
  estruct.variable(1).var = az;
  estruct.variable(1).type = 'ANGLE_RAD';
  
  estruct.variable(2).name = 'el';
  estruct.variable(2).req_dim = [901 1];
  estruct.variable(2).var = el;
  estruct.variable(2).type = 'ELEVATION_RAD';
  
  estruct.variable(3).name = 'prn_pass';
  estruct.variable(3).req_dim = [901 1; 901 2;];
  estruct.variable(3).var = prn_pass;
  
  % Call the error checking function
  stop_flag = err_chk(estruct);
  
  if stop_flag == 1           
    fprintf('Invalid inputs to %s.  Returning with empty outputs.\n\n', ...
             estruct.func_name);
    return
  end % if stop_flag == 1
end % if matlab_version >= 5.0 & isempty(DEBUG_MODE) 

%%%%% END VARIABLE CHECKING CODE %%%%%

%%%%% BEGIN ALGORITHM CODE %%%%%

% Determine how many satellites are involved and plot them 1 at a time
active_sats = [];     % starting value for the active satellites matrix

prn = prn_pass(:,1);
if size(prn_pass,2)==2,,
  pass = prn_pass(:,2);
else,
  pass = ones(size(prn));
end;

prn_nums = unique(prn);
num_prns = length(prn_nums);

for i = 1:num_prns           % loop over possible prn numnbers
  I = find(prn == prn_nums(i));                      % find the matches
  if ~isempty(I)                                % if there is a match, 
    active_sats = [active_sats prn(I(1))]; % add that prn to the active list
  end % if any(I)
end % for

avail_colors = ['gmycrb'];
num_colors = length(avail_colors);

for i = 1:size(active_sats,2)                % loop over the active satellites
  J = find(prn == active_sats(i));     % all satellites with the same prn number 

  % Determine how many passes for this PRN
  pass_sort = sort(pass(J));
  pass_change = find(diff(pass_sort) ~= 0);
  % create a matrix that has sorted and reduced pass numbers [1 2 4 5 6 8 ... 28]
  pass_nums = [pass_sort(pass_change); pass_sort(length(pass_sort))];
  num_passes = length(pass_nums);

  % verify that some satellites were found
  if any(J)
    label_color = avail_colors(rem(i,num_colors) + 1);  % cycle through colors
    for k = 1:num_passes,
      I = find(prn == active_sats(i) & pass == pass_nums(k));   

      % plot the az/el pairs for this satellite
      p_handle = ...
         plotpolr(az(I),el(I),'-',num2str(active_sats(i)),label_color,spoke_label);
    
      % clear out the I variable
      clear I
    
      % make sure that the hold state is on
      if ishold == 0
        hold on
      end % if ishold == 0
    end;
    
  end % if any(I)

end % for
title(plot_title);
zoom on       

% set the plot label to be Satellite Sky Plot if it is not already named
if isempty(get(gcf,'Name'))==1,
  set(gcf,'Name','Satellite Sky Plot')
end;

hold off

%%%%% END ALGORITHM CODE %%%%%

% end PLOTSKY

function hpol = plotpolr(az,el,line_style,prn_label,label_color,spoke_label)

% hpol = plotpolr(az,el,line_style,prn_label,label_color,spoke_label);
%
% Azimuth-Elevation polar coordinate plot. Plots a line based on azimuth and 
% elevation data with optional inputs for labeling and coloring of the line.
%
% Inputs:
%   az           - azimuth vector (rad) (nx1)
%                   valid values are -2*pi -> 2*pi
%   el           - elevation vector (rad) (nx1)
%                   valid values are -pi/2 -> pi/2
%   line_style   - line style to use for this line (string) (optional). 
%                   These are the Matlab character designations for line styles 
%                   [. o x + - * : -. --], default is the Matlab 'auto'
%   prn_label    - label to identify the az/el line (string) (optional)
%                   default is no label
%   label_color  - color for the line and label (string) (optional).  
%                   These are the Matlab letter designations for colors 
%                   [y m c r g b w k], default is the Matlab 'auto'
%   spoke_label  - labels for the North, East, South,and West spokes of the 
%                   plot. (4xn string) (optional).  
%                   default = str2mat('N','E','S','W')
%                  
% Outputs:
%   hpol         - handle to the plot created
%
% See also PLOTSKY, NED2AZEL, ECEF2NED

% Written by: Jimmy LaMance 11/7/96 
% Copyright (c) 1998 by Constell, Inc.

% functions called: none

%%%%% BEGIN VARIABLE CHECKING CODE %%%%%
% declare the global debug variable
global DEBUG_MODE

% Initialize the output variables
p_handle=[];

% Check the number of input arguments and issues a message if invalid
msg = nargchk(2,6,nargin);
if ~isempty(msg)
  fprintf('%s  See help on PLOTPOLR for details.\n',msg);
  fprintf('Returning with empty outputs.\n\n');
  return
end

% check if the line style is provided, if not use the default of auto
if nargin < 3            % no line style variable is provided
  line_style = 'auto';   % set to auto mode (default)
end % if nargin < 3
  
% check if the prn label is provided, if not use the default of '' (no label)
if nargin < 4            % no prn label variable is provided
  prn_label = '';        % set to '' (default)
end % if nargin < 4

% check if the label color is provided, if not use the default of auto
if nargin < 5            % no line style variable is provided
  label_color = '';      % set to auto mode (default)
end % if nargin < 5 

% check that the input spoke labels are correct dimension or set to the 
% default values
if nargin < 6
  spoke_label = str2mat('N','E','S','W');
end % if nargin >= 6          

% Get the current Matlab version
matlab_version = version;
matlab_version = str2num(matlab_version(1));

% If the Matlab version is 5.x and the DEBUG_MODE flag is not set
% then set up the error checking structure and call the error routine.
if matlab_version >= 5.0                        
  estruct.func_name = 'PLOTPOLR';

  % Develop the error checking structure with required dimension, matching
  % dimension flags, and input dimensions.
  estruct.variable(1).name = 'az';
  estruct.variable(1).req_dim = [901 1];
  estruct.variable(1).var = az;
  estruct.variable(1).type = 'ANGLE_RAD';
  
  estruct.variable(2).name = 'el';
  estruct.variable(2).req_dim = [901 1];
  estruct.variable(2).var = el;
  estruct.variable(2).type = 'ELEVATION_RAD';