time   calls  line
                  1 function d = apparentAzEl(d)
                  2 
                  3 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
                  4 %
                  5 %  function d = apparentAzEl(d)
                  6 %
                  7 %  functions that retracts the pointing model and refraction corrections to
                  8 %  go from encoder az/el to sky az/el.
                  9 %
                 10 %  d - data structure
                 11 %  
                 12 %  creates new subfield:
                 13 %    d.antenna0.servo.apparent, which is [Nby4], where each column
                 14 %    corresponds to :
                 15 %    [apparentAzimuth, apparentElevation, error in fit for Az, error in fit
                 16 %    for El];
                 17 %
                 18 %
                 19 %aza is the apparent azimuth
                 20 %ela is the apparent elevation
                 21 %erraz is the error between the antenna coordinate recorder in the data and
                 22 %what we get when we use the apparent position to start with for refraction
                 23 %and pointing calcualtions
                 24 %similarly for erralt
                 25 %
                 26 %  CJC
                 27 %
                 28 %%%%%%%%%%%%%%%%%%%%%%%%%%%%
                 29 % ogk edit 1:
                 30 % Changed the condition in the while loop to
                 31 % Azimuth Error > threshold -> mod(Azimuth Error,360)>threshold
                 32 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
                 33 
                 34 %get the antenna coordinates that we start with
             1   35 azprime=d.antenna0.servo.az; 
             1   36 elprime = d.antenna0.servo.el; 
             1   37 maxitr=20; 
                 38 
                 39 %lets just see what sort of correction we get at this antenna angle (AZ')- 
                 40 %if we assume the difference between AZ (apparent) and AZ'(antenna) is
                 41 %small then we can use this number as a start approximation- here we have 3
                 42 %coordinates Az (apparent AZ) Az' (antenna Az) AZ'' (meaningless azimuth   
                 43 %position calculated by applying a pointing and refraction correction to ...
                 44 %    Az') and we
                 45 %make the assumptio that Az-Az' is approximately Az'-Az''
  1.62       1   46 [azdoubleprime,eldoubleprime]=calcAzEl2(azprime,elprime,d); 
                 47 
                 48 %now we calculate what sort of offset we have, daz and del-note that this
                 49 %offset is between AZ' and AZ''- ie daz=AZ'-AZ''- therefore to go back to
                 50 %AZ we use the equation daz~=AZ-AZ' (using approximation) and therefore ...
                 51 %    AZ=AZ'+daz
                 52 
             1   53 daz=azprime-azdoubleprime; 
  0.01       1   54 del=elprime-eldoubleprime; 
                 55 
                 56 %Now we assume that the difference between the apparent and antenna
                 57 %coordinates is small i.e that the same sort of correction would have been
                 58 %found if we'd done the calculation on the apparent coordinates- defining  
                 59 %apparent coordinates as AZ and antenna coordinates as AZ' we have
                 60 %daz = AZ-AZ' (not the difference and similarity (!!!) with the calculation
                 61 %above                                                          
                 62 % AZ=AZ'+daz
                 63 
             1   64 azapp = azprime+daz; 
  0.01       1   65 elapp = elprime+del; 
                 66 
                 67 %So these are our first guesses for the apparent azimuth and elevation
                 68 %values- they should be ok but lets just check by going from these values
                 69 %back to the antenna values and comparing
                 70 
  1.52       1   71 [azprime2,elprime2]=calcAzEl2(azapp,elapp,d); 
                 72 
             1   73 errazprime = (azprime-azprime2); 
  0.01       1   74 errelprime = (elprime-elprime2); 
                 75 
  0.02       1   76 maxazerr=max(abs(errazprime)); 
  0.01       1   77 maxelerr=max(abs(errelprime)); 
             1   78 vecazerr=[]; 
             1   79 vecelerr=[]; 
  0.01       1   80 a=isnan(daz); 
             1   81 daz(a)=0; 
             1   82 a=isnan(del); 
             1   83 del(a)=0; 
                 84 %Now we iteratively adjust the Az (apparent coordinate) until it produces
                 85 %the 'correct' AZ
                 86 
             1   87 alen=length(daz); 
  0.01       1   88 i=0; 
                 89 %while(((maxazerr >0.0001) || (maxelerr>0.0001)) && (i<maxitr))
                 90  % i=i+1;
                 91   %disp(['Iteration (max): ', num2str(i),'(',num2str(maxitr),')']);
                 92 
                 93 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
                 94 % ogk edit 1: change while loop conditional statement to
                 95 % mod(maxazerr,360)<...
                 96 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
             1   97 while(((mod(maxazerr,360) >0.0001) || (maxelerr>0.0001)) && (i<maxitr)) 
             3   98   i=i+1; 
             3   99   disp(['Iteration (max): ', num2str(i),'(',num2str(maxitr),')']);   
  4.61       3  100   [azprime2,elprime2]=calcAzEl2(azapp,elapp,d); 
  0.11       3  101   errazprime = wrap180(azprime - azprime2); 
  0.07       3  102   errelprime = wrap180(elprime - elprime2); 
  0.02       3  103   a=isnan(errazprime); 
             3  104   errazprime(a)=0; 
             3  105   a=isnan(errelprime); 
  0.01       3  106   errelprime(a)=0; 
                107   
  0.04       3  108   maxazerr=max(abs(errazprime)); 
  0.04       3  109   maxelerr=max(abs(errelprime)); 
             3  110   daz = daz + errazprime; 
             3  111   del = del + errelprime; 
  0.13       3  112   azapp= wrap360(azprime+daz); 
  0.12       3  113   elapp = wrap360(elprime+del); 
             3  114   vecazerr=[vecazerr maxazerr]; 
             3  115   vecelerr=[vecelerr maxelerr]; 
                116 %end
             3  117 end 
                118 
             1  119 if i>=maxitr 
                120 	%Error handling in case the removal of the pointing correction isn't
                121 	% working
                122 	error('Apparent Az/El not converging')
                123 end
                124 %might need some error checking here but otherwise
                125 
             1  126 erraz=errazprime; 
             1  127 errel=errelprime; 
             1  128 aza=azapp; 
             1  129 ela=elapp; 
                130 
  0.01       1  131 d.antenna0.servo.apparent = [aza ela erraz errel]; 
                132 
             1  133 return;