利用MATLAB编制的GPS单点定位程序

1、function t=TimetoJD(Y,M,D,h,f,s)if(Y>=80) Y=Y+1900;else Y=Y+2000;endif M<=2 Y=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% .ApproXYZ3; /appr

2、oximate 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 Jul

3、ian time% .SumOType; /number of types of observables% .SumOOSumOType; /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% .TimeOEpp2; /reciever time of epoch% .SatSum; /number of satellites% .SatCodeSatSum; /satellites' PRN% .Obs

4、_FreL1SatSum; % .Obs_FreL2SatSum;% .Obs_RangeC1SatSum;% .Obs_RangeP1SatSum;% .Obs_RangeP2SatSum;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',

5、9;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<81 s(L+1:81)=' ' end instrS=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(

6、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) HeadODerval=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: DE

7、LTA 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

8、=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=Ti

9、metoJD(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.SumOType f=s(k*6+5:k*6+6); if strcmp(f,'L1') HeadODat.SumOO(1,k)=0; elseif strcmp(f,'L

10、2') 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; end

11、end %头文件结束 elseif strncmp(instrS,'END OF HEADER',13) break; else continue; end end %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(

12、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

13、).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).SatSum f=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

14、存 for k=1:ObsODat(t).SatSum s=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>5 sg=fgets(fid1); s=strcat(s,sg); end L=size(s,2); %补充数据长度 if L<HeadODat.SumOType*16 s(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.SumOType stemp=s(j*16-15:j*1

15、6); stemp=deblank(stemp); if isempty(stemp) continue; end stempNum=str2num(stemp); stempLength=size(stempNum,2); if stempLength>1 stempNum=stempNum(1,1); end if HeadODat.SumOO(1,j)=0 ObsODat(t).Obs_FreL1(1,k)=stempNum; elseif HeadODat.SumOO(1,j)=1 ObsODat(t).Obs_FreL2(1,k)=stempNum; elseif HeadOD

16、at.SumOO(1,j)=2 ObsODat(t).Obs_RangeC1(1,k)=stempNum; elseif HeadODat.SumOO(1,j)=3 ObsODat(t).Obs_RangeP1(1,k)=stempNum; elseif HeadODat.SumOO(1,j)=4 ObsODat(t).Obs_RangeP2(1,k)=stempNum; else continue; end end %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; return fun

17、ction 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(fid

18、1); header=findstr(temp,'END OF HEADER'); if(isempty(header) break; endendi=1;while(1) temp=fgetl(fid1); if(temp=-1) break; end EphDat(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),str2dou

19、ble(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); te

20、mp=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(te

21、mp(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

22、(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 for k= i-1:i if (EphDat(i-1).PRN=EphD

23、at(i).PRN) break; elseif abs(EphDat(i-1).toc-EphDat(i).toc)<0.001 i=i - 1; end end end i=i + 1;endfunction DDDWformat longclear alltic global 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=

24、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:epochNUM tr=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<4 break; %去除无解的历元 end Code=ObsODat(k).SatCode; %该历元观测到的卫星号组 R=ObsODat(k).Obs_RangeC1 ;

25、 %取出C1观测值,列向量 %卫星发射时间的迭代计算 for j=1:Snum if R(j) = 0 continue; end t=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:N if(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; t

26、oe=EphDat(i).toe; dt=a0+(t2-toe)*a1+(t2-toe)2*a2;%卫星钟差 dd=1; break; end end if dd=-1 msgbox('没有相关星历文件'); return; end tt = 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

27、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); end axk = (Xk0-Xs)/ss; ayk = (Yk0-Ys)/ss;

28、azk = (Zk0-Zs)/ss; EAB=CAL2POL(Xk0,Yk0,Zk0,Xs,Ys,Zs); if j=1 A = axk,ayk,azk,1; L = R(j)-ss+c*dt-2.47/(sin(EAB)+0.0121); else A = 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 end end if Snum=4 dx=inv(A)*L; aaaa(k).Q=inv(A'*A); Px(k) = 1/aaaa(k).Q(1,1); Py(k) = 1/aaaa

29、(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 > 4 dx = 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); z

30、change(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,t

31、ime)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:sz if(EphDat(i).PRN=PRN & abs(EphDat(i).toc-t1)<0.0417*2) G=EphDat(i); gg=1; break; endendt3=

32、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.sqa2; %地球长半轴n0=sqrt(u/a3); %计算的平运动 tk=t-G.toe; %从参考历元开始的时间 if tk>=302400 tk=tk-604800;elseif tk<-302400 tk=tk + 604800;endn=n0+G.dn; %改正后的运动 Mk=G.M0+n*tk;Ek=Mk; %偏近

33、点角 弧度for i=1:4 Ek=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.e2)*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=n