findorbitprameters.m

差分载波定位

%找到当前观测时刻用于计算卫星位置的轨道参数
function orbitPrameters = findOrbitPrameters(SatPrn, GPST, navData)
colArr = find(navData(1,:) == SatPrn); %在导航电文信息矩阵navData里有colArr列与卫星PRN号相关的导航电文
time = navData(18,colArr);             %navData的18行是toe,参考时刻

%找到与参考时刻之差小于半小时的colArr列导航电文
for i = 1 : length(time)
    if abs(GPST-time(i)) < 3600 %与参考时刻之差小于半小时
        break;
    end
end
col = colArr(i);
orbitPrameters = navData(:,col);

%orbitPrameters是
% orbitPra.prn      = navData(1,col);
% orbitPra.af2      = navData(2,col);
% orbitPra.M0       = navData(3,col);
% orbitPra.roota    = navData(4,col);
% orbitPra.deltan   = navData(5,col);
% orbitPra.ecc      = navData(6,col);
% orbitPra.omega    = navData(7,col);
% orbitPra.cuc      = navData(8,col);
% orbitPra.cus      = navData(9,col);
% orbitPra.crc      = navData(10,col);
% orbitPra.crs      = navData(11,col);
% orbitPra.i0       = navData(12,col);
% orbitPra.idot     = navData(13,col);
% orbitPra.cic      = navData(14,col);
% orbitPra.cis      = navData(15,col);
% orbitPra.Omega0   = navData(16,col);
% orbitPra.Omegadot = navData(17,col);
% orbitPra.toe      = navData(18,col);
% orbitPra.af0      = navData(19,col);
% orbitPra.af1      = navData(20,col);