www.pudn.com > final-GPS.rar > Error_Tropospheric_Hopfield.m, change:2008-04-06,size:1863b


%This Function approximate Troposspheric Group Delay Base on  
%application . edited by B. Parkinson,J. Spilker, P.Enge, AIAA,1996 
%CopyRight By Moein Mehrtash 
%************************************************************************** 
% Written by Moein Mehrtash, Concordia University, 3/21/2008              * 
% Email: moeinmehrtash@yahoo.com                                          * 
%************************************************************************** 
% Reference:"GPS Theory and application",edited by B.Parkinson,J.Spilker, * 
%**************************************************************************            
%Input 
%        T_amb:'C =>At reciever antenna location 
%        P_amb:hPa =>At reciever antenna location 
%        P_vap:hPa =>Water vapore pressure at reciever antenna location 
%        Pos_Rcv       : XYZ position of reciever               (Meter)  
%        Pos_SV        : XYZ matrix position of GPS satellites  (Meter)  
 
%Output:     
%        Delta_R_Trop: m =>Tropospheric Error Correction 
%**************************************************************************            
function Delta_R_Trop=Error_Tropospheric_Hopfield(T_amb,P_amb,P_vap,Pos_Rcv,Pos_SV) 
S=size(Pos_SV); 
m=S(1);n=S(2); 
for i=1:m 
  [E,A0]=Calc_Azimuth_Elevation(Pos_Rcv,Pos_SV(i,:)); 
  El(i)=E;                                                   %Elevation Rad 
  A(i)=A0;                                                    %Azimoth Rad 
end 
 
%Zenith Hydrostatic Delay 
Kd=1.55208*10^(-4)*P_amb*(40136+148.72*T_amb)/(T_amb+273.16); 
 
%Zenith Wet Delay 
Kw=-.282*P_vap/(T_amb+273.16)+8307.2*P_vap/(T_amb+273.16)^2; 
 
for i=1:m 
  Denom1(i)=sin(sqrt(El(i)^2+1.904*10^-3)); 
  Denom2(i)=sin(sqrt(El(i)^2+.6854*10^-3)); 
  %Troposhpheric Delay Correctoion 
  Delta_R_Trop(i)=Kd/Denom1(i)+Kw/Denom2(i);                        % Meter 
end