nav.julian_day=198;
[ne,nr]=size(textdata);
aa=char(textdata(2:end,1));
nav.param_hour=str2num(aa(:,5:6));
nav.param_minute=str2num(aa(:,8:9));
    nav.param_second=str2num(aa(:,11:19));
    nav.timestamp=datenum(2017,7,18,str2num(aa(:,5:6)),str2num(aa(:,8:9)),str2num(aa(:,11:19)));
clear textdata
nav.hour=data(:,1);
nav.minute=data(:,2);
nav.second=data(:,3);
nav.mag_hdg=data(:,4);
nav.tru_hdg=data(:,5);
nav.gps_alt=data(:,6);
nav.pressure_alt=data(:,7);
nav.gps_lat=data(:,8);
nav.gps_lon=data(:,9);
nav.green_light_echo=data(:,20);
nav.green_light_sensor=data(:,21);
nav.tot_ac_weight=data(:,22);
nav.crosswind=data(:,23);
nav.headwind=data(:,24);
clear data
save('nav_20170718.mat','nav')
clear nav