void ceos_init_alos_stVec(const char *fName, ceos_description *ceos,
meta_parameters *meta)
{
struct pos_data_rec ppdr;
// Read platform position record
get_ppdr(fName,&ppdr);
// Initialize state vector
int vector_count=3;
double data_int = meta->sar->original_line_count / 2
* fabs(meta->sar->azimuth_time_per_pixel);
while (fabs(data_int) > 15.0) {
data_int /= 2;
vector_count = vector_count*2-1;
}
meta->state_vectors = meta_state_vectors_init(vector_count);
meta->state_vectors->vector_count = vector_count;
// Determine image start time
ymd_date imgDate;
julian_date imgJD;
hms_time imgTime;
date_dssr2date(ceos->dssr.inp_sctim, &imgDate, &imgTime);
date_ymd2jd(&imgDate, &imgJD);
double imgSec = date2sec(&imgJD, &imgTime);
imgSec -= ceos->dssr.sc_lin*fabs(meta->sar->azimuth_time_per_pixel);
sec2date(imgSec, &imgJD, &imgTime);
meta->state_vectors->year = (int) imgJD.year;
meta->state_vectors->julDay = (int) imgJD.jd;
meta->state_vectors->second = date_hms2sec(&imgTime);
// Assign position and velocity for center of image
int n = (vector_count - 1)/2;
double timeStart = get_timeDelta(ceos, &ppdr, meta);
double time = timeStart + n*data_int;
stateVector st;
st.pos.x = ppdr.orbit_ele[0];
st.pos.y = ppdr.orbit_ele[1];
st.pos.z = ppdr.orbit_ele[2];
st.vel.x = ppdr.orbit_ele[3];
st.vel.y = ppdr.orbit_ele[4];
st.vel.z = ppdr.orbit_ele[5];
meta->state_vectors->vecs[n].vec = st;
meta->state_vectors->vecs[n].time = time - timeStart;
int ii;
double newTime;
for (ii=0; ii<n; ii++) {
newTime = time - (n - ii)*data_int;
meta->state_vectors->vecs[ii].time = newTime - timeStart;
meta->state_vectors->vecs[ii].vec = propagate(st, time, newTime);
}
for (ii=n+1; ii<vector_count; ii++) {
newTime = time + (vector_count - n - 1)*data_int;
meta->state_vectors->vecs[ii].time = newTime - timeStart;
meta->state_vectors->vecs[ii].vec = propagate(st, time, newTime);
}
}
/***************************************************************
* Get_timeDelta:
* Return the time difference, in seconds, between the start
* of the state vectors (in the PPDR) and the start of the image
* (as described in the DSSR). Write this time to the given
* meta_parameters->state_vectors structure.*/
double get_timeDelta(ceos_description *ceos,struct pos_data_rec *ppdr,meta_parameters *meta)
{
ymd_date imgDate;
julian_date imgJD,stJD;
hms_time imgTime,stTime;
double imgSec,stSec;/*Seconds since 1900 for start of image and start of state vectors*/
/*Read time of *start* of state vectors*/
stJD.year = (int) ppdr->year;
stJD.jd = (int) ppdr->gmt_day;
date_sec2hms(ppdr->gmt_sec,&stTime);
stSec=date2sec(&stJD,&stTime);
/*Compute the *scene* start time from the CEOS DSSR: */
/* begin with scene center time */
if (ceos->facility == BEIJING)
date_dssr2time(ceos->dssr.inp_sctim,&imgDate,&imgTime);
else
date_dssr2date(ceos->dssr.inp_sctim,&imgDate,&imgTime);
date_ymd2jd(&imgDate,&imgJD);
imgSec=date2sec(&imgJD,&imgTime);
if (ceos->processor==FOCUS && ceos->product==CCSD) {
/* do nothing-- dssr "inp_sctim" already gives scene start time */
}
else if (0!=strcmp(ceos->dssr.az_time_first,""))
{ /* e.g., ESA data. "az_time_first" field gives start of image */
date_dssr2time(ceos->dssr.az_time_first,&imgDate,&imgTime);
imgSec=date2sec(&imgJD,&imgTime);
}
else if (ceos->facility==EOC)
{
imgSec-=ceos->dssr.sc_lin*fabs(meta->sar->azimuth_time_per_pixel);
}
else {/*Convert scene center time to scene *start* time, by
subtracting off the center line # * the time/line */
imgSec-=ceos->dssr.sc_lin*fabs(meta->sar->azimuth_time_per_pixel);
}
/*
// Complex ALOS data have an additional 1 sec shift
// Still under investigation: Need word from DQ on this
if (ceos->facility==EOC && ceos->product==SLC)
imgSec -= 1.0;
*/
/*Convert scene center # of seconds back to date/time*/
sec2date(imgSec,&imgJD,&imgTime);
/*Write image time to meta->state_vectors structure*/
meta->state_vectors->year = (int) imgJD.year;
meta->state_vectors->julDay = (int) imgJD.jd;
meta->state_vectors->second = date_hms2sec(&imgTime);
/*Return the time between state vector start and image start*/
return stSec-imgSec;
}
// input is seconds since midnight Jan 1, 1900
// output is a string of the form "MM/DD HH:MM"
const char *date_str(double s)
{
julian_date jd;
hms_time t;
ymd_date d;
static char buf[64];
sec2date(s, &jd, &t);
date_jd2ymd(&jd, &d);
sprintf(buf, "%02d/%02d %02d:%02d", d.month, d.day, t.hour, t.min);
return buf;
}
main()
{
long sec;
date d;
puts("请输入日期(格式为2008-08-08 08:08:08)：");
scanf("%d-%d-%d %d:%d:%d",&d.year,&d.month,&d.day,&d.hour,&d.min,&d.sec);
sec=date2sec(d);
printf("到格林时间%d秒!\n",sec);
puts("请到格林时间的秒数：");
scanf("%d",&sec);
d=sec2date(sec);
printf("日期为:%d-%d-%d %d:%d:%d\n",d.year,d.month,d.day,d.hour,d.min,d.sec);
}
// input is seconds since midnight Jan 1, 1900
// output is a string of the form "DD-MON-YYYY HH:MM"
const char *date_str_long(double s)
{
char mon[][5]=
{"","Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"};
julian_date jd;
hms_time t;
ymd_date d;
static char buf[64];
sec2date(s, &jd, &t);
date_jd2ymd(&jd, &d);
sprintf(buf, "%02d-%s-%4d, %02d:%02d:%02d", d.day, mon[d.month], d.year,
t.hour, t.min, (int)(t.sec+.5));
return buf;
}
/*
Compute the average ymd_date date and hms_time time
-----------------------------------------------------*/
void average_ymdTimes(ymd_date *date1, ymd_date *date2,
hms_time *time1, hms_time *time2,
ymd_date *ave_date, hms_time *ave_time)
{
double secs1, secs2, ave_secs;
julian_date jd_1, jd_2, ave_jd;
date_ymd2jd(date1, &jd_1); // Julian date contains year and day number within that year
date_ymd2jd(date2, &jd_2);
secs1 = date2sec(&jd_1, time1); // Seconds from midnight, Jan 1, 1900 to julian date plus seconds into that day
secs2 = date2sec(&jd_2, time2);
ave_secs = (secs1 + secs2) / 2.0;
sec2date(ave_secs, &ave_jd, ave_time);
date_jd2ymd(&ave_jd, ave_date);
}
