RTKlib软件源码学习（观测文件与星历文件读取）

本文基于本人对rtklib源码的学习进行顺序汇总，为记录个人的学习与理解，并根据个人需要对部分代码对其进行注释，如有错误或者不完善的地方烦请提出建议或改正方法。

目录

1、execses函数

2、readobsnav函数

3、readrnxt函数

4、readrnxfile函数

5、readrnxfp函数

5.1、readrnxh函数

 5.1.1、decode_obsh函数

 5.1.2、decode_navh函数

5.1.3、decode_gnavh和decode_hnavh函数

5.2、readrnxobs函数

 5.2.1、readrnxobsb函数

5.2.2、 addobsdata

5.3、readrnxnav函数

5.3.1、readrnxnavb函数

5.3.2 、add_eph函数

5.3.3、add_geph函数

5.3.4、add_seph函数

 5.4、readrnxclk函数

1、execses函数

/* execute processing session ------------------------------------------------*/
static int execses(gtime_t ts, gtime_t te, double ti, const prcopt_t *popt,
                   const solopt_t *sopt, const filopt_t *fopt, int flag,
                   char **infile, const int *index, int n, char *outfile)
{
    FILE *fp,*fptm;
    rtk_t *rtk_ptr = (rtk_t *)malloc(sizeof(rtk_t)); /* moved from stack to heap to avoid stack overflow warning */
    prcopt_t popt_=*popt;
    solopt_t tmsopt = *sopt;
    char tracefile[1024],statfile[1024],path[1024],*ext,outfiletm[1024]={0};
    int i,j,k;
    
    trace(3,"execses : n=%d outfile=%s\n",n,outfile);
    
    /* open debug trace */
    if (flag&&sopt->trace>0) {
        if (*outfile) {
            strcpy(tracefile,outfile);
            strcat(tracefile,".trace");
        }
        else {
            strcpy(tracefile,fopt->trace);
        }
        traceclose();
        traceopen(tracefile);
        tracelevel(sopt->trace);
    }
    /* read ionosphere data file */
    if (*fopt->iono&&(ext=strrchr(fopt->iono,'.'))) {
        if (strlen(ext)==4&&(ext[3]=='i'||ext[3]=='I')) {
            reppath(fopt->iono,path,ts,"","");
            readtec(path,&navs,1);
        }
    }
    /* read erp data */
    if (*fopt->eop) {
        free(navs.erp.data); navs.erp.data=NULL; navs.erp.n=navs.erp.nmax=0;
        reppath(fopt->eop,path,ts,"","");
        if (!readerp(path,&navs.erp)) {
            showmsg("error : no erp data %s",path);
            trace(2,"no erp data %s\n",path);
        }
    }
    /* read obs and nav data */
    if (!readobsnav(ts,te,ti,infile,index,n,&popt_,&obss,&navs,stas)) {
        /* free obs and nav data */
        freeobsnav(&obss, &navs);
        free(rtk_ptr);
        return 0;
    }//通过这部分调用readobsnav来对观测文件和星历文件进行读取
    
    /* read dcb parameters */
    if (*fopt->dcb) {
        reppath(fopt->dcb,path,ts,"","");
        readdcb(path,&navs,stas);
    } else {
        for (i=0;i<3;i++) {
            for (j=0;j<MAXSAT;j++) navs.cbias[j][i]=0;
            for (j=0;j<MAXRCV;j++) for (k=0;k<2;k++) navs.rbias[j][k][i]=0;
        }
    }
    /* set antenna parameters */
    if (popt_.mode!=PMODE_SINGLE) {
        setpcv(obss.n>0?obss.data[0].time:timeget(),&popt_,&navs,&pcvss,&pcvsr,
               stas);
    }
    /* read ocean tide loading parameters */
    if (popt_.mode>PMODE_SINGLE&&*fopt->blq) {
        readotl(&popt_,fopt->blq,stas);
    }
    /* rover/reference fixed position */
    if (popt_.mode==PMODE_FIXED) {
        if (!antpos(&popt_,1,&obss,&navs,stas,fopt->stapos)) {
            freeobsnav(&obss,&navs);
            free(rtk_ptr);
            return 0;
        }
        if (!antpos(&popt_,2,&obss,&navs,stas,fopt->stapos)) {
            freeobsnav(&obss,&navs);
            free(rtk_ptr);
            return 0;
        }
    }
    else if (PMODE_DGPS<=popt_.mode&&popt_.mode<=PMODE_STATIC_START) {
        if (!antpos(&popt_,2,&obss,&navs,stas,fopt->stapos)) {
            freeobsnav(&obss,&navs);
            free(rtk_ptr);
            return 0;
        }
    }
    /* open solution statistics */
    if (flag&&sopt->sstat>0) {
        strcpy(statfile,outfile);
        strcat(statfile,".stat");
        rtkclosestat();
        rtkopenstat(statfile,sopt->sstat);
    }
    /* write header to output file */
    if (flag&&!outhead(outfile,infile,n,&popt_,sopt)) {
        freeobsnav(&obss,&navs);
        free(rtk_ptr);
        return 0;
    }
    /* name time events file */
    namefiletm(outfiletm,outfile);
    /* write header to file with time marks */
    outhead(outfiletm,infile,n,&popt_,&tmsopt);

    iobsu=iobsr=isbs=revs=aborts=0;
    
    if (popt_.mode==PMODE_SINGLE||popt_.soltype==0) {
        if ((fp=openfile(outfile)) && (fptm=openfile(outfiletm))) {
            procpos(fp,fptm,&popt_,sopt,rtk_ptr,0); /* forward */
            fclose(fp);
            fclose(fptm);
        }
    }
    else if (popt_.soltype==1) {
        if ((fp=openfile(outfile)) && (fptm=openfile(outfiletm))) {
            revs=1; iobsu=iobsr=obss.n-1; isbs=sbss.n-1;
            procpos(fp,fptm,&popt_,sopt,rtk_ptr,0); /* backward */
            fclose(fp);
            fclose(fptm);
        }
    }
    else { /* combined */
        solf=(sol_t *)malloc(sizeof(sol_t)*nepoch);
        solb=(sol_t *)malloc(sizeof(sol_t)*nepoch);
        rbf=(double *)malloc(sizeof(double)*nepoch*3);
        rbb=(double *)malloc(sizeof(double)*nepoch*3);
        
        if (solf&&solb) {
            isolf=isolb=0;
            procpos(NULL,NULL,&popt_,sopt,rtk_ptr,1); /* forward */
            revs=1; iobsu=iobsr=obss.n-1; isbs=sbss.n-1;
            procpos(NULL,NULL,&popt_,sopt,rtk_ptr,1); /* backward */
            
            /* combine forward/backward solutions */
            if (!aborts&&(fp=openfile(outfile))  && (fptm=openfile(outfiletm))) {
                combres(fp,fptm,&popt_,sopt);
                fclose(fp);
                fclose(fptm);
            }
        }
        else showmsg("error : memory allocation");
        free(solf);
        free(solb);
        free(rbf);
        free(rbb);
    }
    /* free rtk, obs and nav data */
    rtkfree(rtk_ptr);
    free(rtk_ptr);
    freeobsnav(&obss,&navs);
    
    return aborts?1:0;
}

execses目前只是把函数放在这里，以此来展示最初调用readobsnav函数的部分

2、readobsnav函数

/* read obs and nav data -----------------------------------------------------*/
static int readobsnav(gtime_t ts, gtime_t te, double ti, char **infile,
                      const int *index, int n, const prcopt_t *prcopt,
                      obs_t *obs, nav_t *nav, sta_t *sta)
{
    int i,j,ind=0,nobs=0,rcv=1;
    
    trace(3,"readobsnav: ts=%s n=%d\n",time_str(ts,0),n);
    
    obs->data=NULL; obs->n =obs->nmax =0;
    nav->eph =NULL; nav->n =nav->nmax =0;
    nav->geph=NULL; nav->ng=nav->ngmax=0;
    /* free(nav->seph); */ /* is this needed to avoid memory leak??? */
    nav->seph=NULL; nav->ns=nav->nsmax=0;
    nepoch=0;
    //给各个指针数据赋初值为空以及0
    for (i=0;i<n;i++) {
        if (checkbrk("")) return 0;
        
        if (index[i]!=ind) {
            if (obs->n>nobs) rcv++;
            ind=index[i]; nobs=obs->n; 
        }
        /* read rinex obs and nav file */
        if (readrnxt(infile[i],rcv,ts,te,ti,prcopt->rnxopt[rcv<=1?0:1],obs,nav,
                     rcv<=2?sta+rcv-1:NULL)<0) {
            checkbrk("error : insufficient memory");
            trace(1,"insufficient memory\n");
            return 0;
        }//调用readrnxt函数对观测文件进行读取
    }
    if (obs->n<=0) {
        checkbrk("error : no obs data");
        trace(1,"\n");
        return 0;
    }//检测观测文件是否正常
    if (nav->n<=0&&nav->ng<=0&&nav->ns<=0) {
        checkbrk("error : no nav data");
        trace(1,"\n");
        return 0;
    }//检测星历文件是否正常
    /* sort observation data */
    nepoch=sortobs(obs);
    //按照时间、接收机、卫星来分类观测信息

    /* delete duplicated（重复） ephemeris */
    uniqnav(nav);
   

    /* set time span for progress display */
    if (ts.time==0||te.time==0) {
        for (i=0;   i<obs->n;i++) if (obs->data[i].rcv==1) break;
        for (j=obs->n-1;j>=0;j--) if (obs->data[j].rcv==1) break;
        if (i<j) {
            if (ts.time==0) ts=obs->data[i].time;
            if (te.time==0) te=obs->data[j].time;
            settspan(ts,te);
        }
    }
    return 1;
}

readobsnav函数首先对所有数据指针赋0初值，然后再检验观测文件或者星历文件是否存在，并调用readrnx函数对文件进行下一步判断。

3、readrnxt函数

extern int readrnxt(const char *file, int rcv, gtime_t ts, gtime_t te,
                    double tint, const char *opt, obs_t *obs, nav_t *nav,
                    sta_t *sta)
{
    int i,n,stat=0;
    const char *p;
    char type=' ',*files[MAXEXFILE]={0};
    
    trace(3,"readrnxt: file=%s rcv=%d\n",file,rcv);
    
    if (!*file) {
        return readrnxfp(stdin,ts,te,tint,opt,0,1,&type,obs,nav,sta);
    }
    for (i=0;i<MAXEXFILE;i++) {
        if (!(files[i]=(char *)malloc(1024))) {
            for (i--;i>=0;i--) free(files[i]);
            return -1;
        }
    }//为每个输入文件分配地址
    /* expand wild-card */
    if ((n=expath(file,files,MAXEXFILE))<=0) {
        for (i=0;i<MAXEXFILE;i++) free(files[i]);
        return 0;
    }//扩大通配符，不清楚具体有什么用
    /* read rinex files */
    for (i=0;i<n&&stat>=0;i++) {
        stat=readrnxfile(files[i],ts,te,tint,opt,0,rcv,&type,obs,nav,sta);
    }//解压和读rinex文件
    /* if station name empty, set 4-char name from file head */
    if (type=='O'&&sta) {
        if (!(p=strrchr(file,FILEPATHSEP))) p=file-1;
        if (!*sta->name) setstr(sta->name,p+1,4);
    }//如果测站名字为空，就给依据文件自动赋4个字符的名字
    for (i=0;i<MAXEXFILE;i++) free(files[i]);释放文件内存
    
    return stat;
}
/* read RINEX OBS and NAV files -----------------