利用MATLAB编制的GPS单点定位程序

function t=TimetoJD(Y,M,D,h,f,s)if(Y>=80)Y=Y+1900;elseY=Y+2000;endif M<=2Y=Y-1;M=M+12;endJD=fix(365.25*Y)+fix(30.6001*(M+1))+D+h/24+f/1440+s/24/3600+1720981.5;t=JD-2444244.5;function [head,obs]=ReadObsData%读接收机观测数据文件%HeadODat :a structure stores header information if o-file% .ApproXYZ[3]; //approximate coordinate% .interval; //intervals of two adjacent epochs% .SiteName; //point name% .Ant_H; //antenna height% .Ant_E; //east offset of the antenna center% .Ant_N; //north offset of then antenna center% .TimeOB; //first epoch time in modifuied Julian time% .TimeOE; //last epoch time in modifuied Julian time% .SumOType; //number of types of observables% .SumOO[SumOType]; //type of observables 0-L1,1-L2,2-C1,3-P1,4-P2,5-D1,6-D2,%ObsODat :a structure stores observables by one and one epoch% .TimeOEpp[2]; //reciever time of epoch% .SatSum; //number of satellites% .SatCode[SatSum]; //satellites' PRN% .Obs_FreL1[SatSum];% .Obs_FreL2[SatSum];% .Obs_RangeC1[SatSum];% .Obs_RangeP1[SatSum];% .Obs_RangeP2[SatSum];global HeadODat;global ObsODat;[fname,fpath]=uigetfile('*.*','选择一个O文件');O_filename=strcat(fpath,fname);fid1=fopen(O_filename,'rt');if (fid1==-1)msgbox('file invalide','warning','warn');return;end%将文件头数据存入结构体HeadODat中t=0;while(t<100)s=fgets(fid1);t=t+1;L=size(s,2);if L<81s(L+1:81)=' ';endinstrS=s(61:81);%测站点近似坐标if strncmp(instrS,'APPROX POSITION XYZ',19)HeadODat.ApproXYZ=zeros(1,3);HeadODat.ApproXYZ(1,1)=str2num(s(1:14));HeadODat.ApproXYZ(1,2)=str2num(s(15:28));HeadODat.ApproXYZ(1,3)=str2num(s(29:42));%历元间隔;elseif strncmp(instrS,'INTERVAL',8)HeadODat.interval=str2num(s(5:11));%测站点号elseif strncmp(instrS,'MARKER NAME',11)HeadODat.SiteName=s(1:4)%天线中心改正elseif strncmp(instrS,'ANTENNA: DELTA H/E/N',20)HeadODat.Ant_H=str2num(s(1:14));HeadODat.Ant_E=str2num(s(15:28));HeadODat.Ant_N=str2num(s(29:42));%第一个历元时间elseif strncmp(instrS,'TIME OF FIRST OBS',17)year=str2num(s(1:6));month=str2num(s(7:12));day=str2num(s(13:18));hour=str2num(s(19:24));minute=str2num(s(25:30));second=str2num(s(31:42));HeadODat.TimeOB=TimetoJD(year,month,day,hour,minute,second);%最后一个历元时间elseif strncmp(instrS,'TIME OF LAST OBS',16)year=str2num(s(1:6));month=str2num(s(7:12));day=str2num(s(13:18));hour=str2num(s(19:24));minute=str2num(s(25:30));second=str2num(s(31:42));HeadODat.TimeOE=TimetoJD(year,month,day,hour,minute,second);%观测值类型elseif strncmp(instrS,'# / TYPES OF OBSERV',19)HeadODat.SumOType=str2num(s(1:6));HeadODat.SumOO=ones(1,HeadODat.SumOType)*-1;for k=1:HeadODat.SumOTypef=s(k*6+5:k*6+6);if strcmp(f,'L1')HeadODat.SumOO(1,k)=0;elseif strcmp(f,'L2')HeadODat.SumOO(1,k)=1;elseif strcmp(f,'C1')HeadODat.SumOO(1,k)=2;elseif strcmp(f,'P1')HeadODat.SumOO(1,k)=3;elseif strcmp(f,'P2')HeadODat.SumOO(1,k)=4;elseif strcmp(f,'D1')HeadODat.SumOO(1,k)=5;elseif strcmp(f,'D2')HeadODat.SumOO(1,k)=6;endend%头文件结束elseif strncmp(instrS,'END OF HEADER',13)break;elsecontinue;endend%观测数据结构体%观测数据结构t=0;while ~feof(fid1)%每个历元的第一行数据，时间和观测到的卫星号s=fgets(fid1);t=t+1;year=str2num(s(1:3));month=str2num(s(4:6));day=str2num(s(7:9));hour=str2num(s(10:12));minute=str2num(s(13:15));second=str2num(s(16:26));%历元时间ObsODat(t).TimeOEp=[year,month,day,hour,minute,second];ObsODat(t).TimeOEpp=TimetoJD(year,month,day,hour,minute,second);%该历元观测到的卫星数ObsODat(t).SatSum=str2num(s(30:32));%该历元观测到的卫星号ObsODat(t).SatCode=zeros(1,ObsODat(t).SatSum);ObsODat(t).Obs_FreL1=zeros(1,ObsODat(t).SatSum);ObsODat(t).Obs_FreL2=zeros(1,ObsODat(t).SatSum);ObsODat(t).Obs_RangeC1=zeros(1,ObsODat(t).SatSum);ObsODat(t).Obs_RangeP1=zeros(1,ObsODat(t).SatSum);ObsODat(t).Obs_RangeP2=zeros(1,ObsODat(t).SatSum);for k=1:ObsODat(t).SatSumf=s(31+k*3:32+k*3);ObsODat(t).SatCode(1,k)=str2num(f);end%每个历元的观测数据，按卫星号先后顺序分行存for k=1:ObsODat(t).SatSums=fgets(fid1);%判断一个卫星的观测数据是否分两行存储，如果为两行，则再读入一行if HeadODat.SumOType>5sg=fgets(fid1);s=strcat(s,sg);endL=size(s,2);%补充数据长度if L<HeadODat.SumOType*16s(L+1:HeadODat.SumOType*16)=' ';end%对观测数据判断其类型，并存储到相应的数组中for j=1:HeadODat.SumOTypestemp=s(j*16-15:j*16);stemp=deblank(stemp);if isempty(stemp)continue;endstempNum=str2num(stemp);stempLength=size(stempNum,2);if stempLength>1stempNum=stempNum(1,1);endif HeadODat.SumOO(1,j)==0ObsODat(t).Obs_FreL1(1,k)=stempNum;elseif HeadODat.SumOO(1,j)==1ObsODat(t).Obs_FreL2(1,k)=stempNum;elseif HeadODat.SumOO(1,j)==2ObsODat(t).Obs_RangeC1(1,k)=stempNum;elseif HeadODat.SumOO(1,j)==3ObsODat(t).Obs_RangeP1(1,k)=stempNum;elseif HeadODat.SumOO(1,j)==4ObsODat(t).Obs_RangeP2(1,k)=stempNum;elsecontinue;endend%完成一个卫星的所有观测数据存储end%完成一个历元的数据存储end%完成所有历元的数据存储head=HeadODat;obs=ObsODat;returnfunction EphDat=ReadGpsDataglobal EphDatEphDat=struct;[filename,pathname]=uigetfile('*.**N','读取GPS广播星历文件'); fid1=fopen(strcat(pathname,filename),'rt');if(fid1==-1)msgbox('Input File or Path is not correct','warning ','warn');return;endwhile(1)temp=fgetl(fid1);header=findstr(temp,'END OF HEADER');if(~isempty(header))break;endendi=1;while(1)temp=fgetl(fid1);break;endEphDat(i).PRN=str2double(temp(1:2));year=str2double(temp(3:5));EphDat(i).toc=TimetoJD(year,str2double(temp(6:8)),str2double(temp(9:11)),str2double(temp(12: 14)),str2double(temp(15:17)),str2double(temp(18:22)));EphDat(i).a0=str2num(temp(23:41));EphDat(i).a1=str2num(temp(42:60));EphDat(i).a2=str2num(temp(61:79));temp=fgetl(fid1);EphDat(i).idoe=str2num(temp(4:22));EphDat(i).Crs=str2num(temp(23:41));EphDat(i).dn=str2num(temp(42:60));EphDat(i).M0=str2num(temp(61:79));temp=fgetl(fid1);EphDat(i).Cuc=str2num(temp(4:22));EphDat(i).e=str2num(temp(23:41));EphDat(i).Cus=str2num(temp(42:60));EphDat(i).sqa=str2num(temp(61:79));temp=fgetl(fid1);EphDat(i).toe=str2num(temp(4:22));EphDat(i).Cic=str2num(temp(23:41));EphDat(i).omg0=str2num(temp(42:60));EphDat(i).Cis=str2num(temp(61:79));temp=fgetl(fid1);EphDat(i).i0=str2num(temp(4:22));EphDat(i).Crc=str2num(temp(23:41));EphDat(i).w=str2num(temp(42:60));EphDat(i).omg=str2num(temp(61:79));temp=fgetl(fid1);EphDat(i).iDot=str2num(temp(4:22));EphDat(i).cflgl2=str2num(temp(23:41));EphDat(i).weekno=str2num(temp(42:60));EphDat(i).pflgl2=str2num(temp(61:79));temp=fgetl(fid1);EphDat(i).svacc=str2num(temp(4:22));EphDat(i).svhlth=str2num(temp(23:41));EphDat(i).tgd=str2num(temp(42:60));EphDat(i).aodc=str2num(temp(61:79));temp=fgetl(fid1);EphDat(i).ttm=str2num(temp(4:22));if(i~=1) %删除重复数据if (EphDat(i-1).PRN~=EphDat(i).PRN)break;elseif abs(EphDat(i-1).toc-EphDat(i).toc)<0.001i=i - 1;endendendi=i + 1;endfunction DDDWformat longclear allticglobal HeadODat;global ObsODat;global EphDat;%先读N文件，再读O文件EphDat=ReadGpsData;[HeadODat,ObsODat]=ReadObsData;%多个历元加权平均求测站点坐标N = size(EphDat,2);c=299792458;epochNUM=size(ObsODat,2);%观测数据的个数Xk0=HeadODat.ApproXYZ(1,1); %测站点的近似坐标Yk0=HeadODat.ApproXYZ(1,2);Zk0=HeadODat.ApproXYZ(1,3);for k=1:epochNUMtr=ObsODat(k).TimeOEp;%历元接收数据时间Snum=ObsODat(1,k).SatSum; %该历元观测到的卫星数if Snum<4break; %去除无解的历元endCode=ObsODat(k).SatCode;%该历元观测到的卫星号组R=ObsODat(k).Obs_RangeC1 ; %取出C1观测值,列向量%卫星发射时间的迭代计算for j=1:Snumif R(j) == 0continue;endt=TimetoJD(tr(1),tr(2),tr(3),tr(4),tr(5),tr(6));t2 = mod(t,7)*24*3600;%gps second%卫星钟差dd=-1;for i=1:Nif(EphDat(i).PRN==Code(j)&abs(t-EphDat(i).toc)<0.0417*2)%读入时间相近的星历文件a0= EphDat(i).a0;a1=EphDat(i).a1;a2= EphDat(i).a2;toe=EphDat(i).toe;dt=a0+(t2-toe)*a1+(t2-toe)^2*a2;%卫星钟差dd=1;break;endendif dd==-1msgbox('没有相关星历文件');return;endtt = tr;ts = tr(6) - R(j)/c;%用秒进行迭代sign = 1;while(sign>1E-8)tt(6) = ts;[Xs1,Ys1,Zs1]= CalPos(Code(j),tt);ss1 = sqrt((Xk0-Xs1)^2+(Yk0-Ys1)^2+(Zk0-Zs1)*(Zk0-Zs1));%卫星位置加地球自转改正qe=0.000072921151467; %地球自转角速度delt=ss1/c;Rotation=[cos(qe*delt),sin(qe*delt),0;-sin(qe*delt),cos(qe*delt),0;0,0,1];h=Rotation*[Xs1;Ys1;Zs1] ;Xs=h(1);Ys=h(2);Zs=h(3);ss = sqrt((Xk0-Xs)^2+(Yk0-Ys)^2+(Zk0-Zs)*(Zk0-Zs));ts = tr(6)-ss/c;sign = norm(ts-tt(6));endaxk = (Xk0-Xs)/ss;ayk = (Yk0-Ys)/ss;azk = (Zk0-Zs)/ss;EAB=CAL2POL(Xk0,Yk0,Zk0,Xs,Ys,Zs);if j==1A = [axk,ayk,azk,1];L = R(j)-ss++c*dt-2.47/(sin(EAB)+0.0121);elseA = [A;axk,ayk,azk,1]; %构造误差方程L = [L;(R(j)-ss++c*dt)-2.47/(sin(EAB)+0.0121)];%常数项endendif Snum==4dx=inv(A)*L;aaaa(k).Q=inv(A'*A);Px(k) = 1/aaaa(k).Q(1,1);Py(k) = 1/aaaa(k).Q(2,2);Pz(k) = 1/aaaa(k).Q(3,3);xchange(k) = dx(1);ychange(k) = dx(2);zchange(k) = dx(3);elseif Snum > 4dx = inv(A'*A)*A'*L; %构造法方程并求解aaaa(k).Q=inv(A'*A);Px(k) = 1/aaaa(k).Q(1,1);Py(k) = 1/aaaa(k).Q(2,2);Pz(k) = 1/aaaa(k).Q(3,3);xchange(k) = dx(1);ychange(k) = dx(2);zchange(k) = dx(3);endendXp=sum(Px.*(Xk0+xchange))/sum(Px)Yp=sum(Py.*(Yk0+ychange))/sum(Py)Zp=sum(Pz.*(Zk0+zchange))/sum(Pz)figure(1);subplot(3,1,1);plot(xchange,'black--');subplot(3,1,2);plot(ychange,'black--');subplot(3,1,3);plot(zchange,'black--');tocfunction [x,y,z]= CalPos(PRN,time)global EphDatt1=TimetoJD(time(1),time(2),time(3),time(4),time(5),time(6));t2=TimetoJD(time(1),time(2),time(3),0,0,0);if isempty(EphDat)EphDat=ReadGpsData;endsz=size(EphDat,2);gg=0;%判断最近的时间for i=1:szif(EphDat(i).PRN==PRN & abs(EphDat(i).toc-t1)<0.0417*2)G=EphDat(i);gg=1;break;endendt3=t2-G.weekno*7;% 减整周数t=t3*24*3600+time(4)*3600+time(5)*60+time(6);%化为GPS秒u=3.986004418E+14; %地球引力常数we=7.2921151467E-5; %地球自转速度a=G.sqa^2; %地球长半轴n0=sqrt(u/a^3); %计算的平运动tk=t-G.toe; %从参考历元开始的时间if tk>=302400tk=tk-604800;elseif tk<-302400tk=tk + 604800;endn=n0+G.dn; %改正后的运动Mk=G.M0+n*tk;Ek=Mk; %偏近点角弧度for i=1:4Ek=Mk+G.e*sin(Ek);endfk=2*atan((sqrt((1+G.e)/(1-G.e))*tan(Ek/2))); %真近点角if(fk<0)fk=fk+2*pi;endcosf=(cos(Ek)-G.e)/(1-G.e*cos(Ek));sinf=(sqrt(1-G.e^2)*sin(Ek))/(1-G.e*cos(Ek));uk=fk+G.w; %升交角矩及轨道摄动改正项iuk=G.Cuc*cos(2*uk)+G.Cus*sin(2*uk);irk=G.Crc*cos(2*uk)+G.Crs*sin(2*uk);iik=G.Cic*cos(2*uk)+G.Cis*sin(2*uk);uk=uk+iuk ; %改正后的升角距r=a*(1-G.e*cos(Ek))+irk; %改正后的地心相径i=G.i0+iik+G.iDot*tk; %改正后的倾角xx=r*cos(uk); %在轨道面中的位置yy=r*sin(uk);omg=G.omg0+(G.omg-we)*tk-we*G.toe; %改正后的升交点经度x=xx*cos(omg)-yy*cos(i)*sin(omg);y=xx*sin(omg)+yy*cos(i)*cos(omg);z=yy*sin(i);CalPos=[x,y,z];%打印结果% x=num2str(x,'%12.6f');% y=num2str(y,'%12.6f');% z=num2str(z,'%12.6f');% fprintf('卫星号PRN:%2.0f',PRN); fprintf('\n');% fprintf('时间time:%4.0f%4.0f%4.0f%4.0f%4.0f%4.1f',time); fprintf('\n');% fprintf('所求卫星在地心坐标系中的空间坐标为：\n');% fprintf('X = ');fprintf(x,'\n');fprintf('m\n');% fprintf('Y = ');fprintf(y,'\n');fprintf('m\n');% fprintf('Z = ');fprintf(z,'\n');fprintf('m\n');%returnfunction EAB=CAL2POL(X,Y,Z,XB,YB,ZB)format longL=atan(Y/X);R=sqrt(X*X+Y*Y+Z*Z);a=6378137;e=sqrt(0.0066943799013);seta=atan(Z/sqrt(X*X+Y*Y));B=asin(sqrt((a*a-R*R*cos(seta)*cos(seta))/(a*a-R*R*cos(seta)*cos(seta)*e*e)))B1=atan(tan(seta)*(1+a*e*e*sin(B)/Z/sqrt(1-e*e*sin(B)*sin(B))));while abs(B1-B)>0.01*pi/180/3600B=B1;B1=atan(tan(seta)*(1+a*e*e*sin(B)/Z/sqrt(1-e*e*sin(B)^2)));endH=R*cos(seta)/cos(B)-(a/sqrt(1-e*e*sin(B)*sin(B)));L=L*180/pi;B=B*180/pi;DX=XB-X;DY=YB-Y;DZ=ZB-Z;NB=-sin(B)*cos(L)*DX-sin(B)*sin(L)*DY+cos(B)*DZ; EB=-sin(L)*DX+cos(L)*DY;UB=cos(B)*cos(L)*DX+cos(B)*sin(L)*DY+sin(B)*DZ; SAB=sqrt(NB*NB+UB*UB+EB*EB);EAB=asin(UB/SAB);。