int read_hdrfile(char *infile)
{
SEASAT_header_ext *hdr;
FILE *fp = fopen(infile,"r");
int val, i, end_line;
double dtmp, t, t1;
int clock_drift_hist[MAX_CLOCK_DRIFT];
int clock_drift_median;
double clock_shift;
if (fp==NULL) {printf("ERROR: can't open %s header file\n",infile); return(1); }
hdr = (SEASAT_header_ext *) malloc(sizeof(SEASAT_header_ext));
for (i=0; i<start_line; i++) {
val = get_values(fp, hdr);
if (val!=20) {printf("ERROR: unable to read to specified start line in header file\n"); exit(1);}
}
station_code = hdr->station_code;
start_year = 1970 + hdr->lsd_year;
start_date = hdr->day_of_year;
start_sec = (double) hdr->msec / 1000.0;
s_date.year = 1970 + hdr->lsd_year;
s_date.jd = hdr->day_of_year;
dtmp = (double) hdr->msec / 1000.0;
date_sec2hms(dtmp,&s_time);
if (USE_CLOCK_DRIFT==1) {
for (i=0; i<MAX_CLOCK_DRIFT; i++) clock_drift_hist[i] = 0;
end_line = start_line + npatches*patch_size;
for (i = start_line; i<end_line; i++) {
val = get_values(fp, hdr);
if (val!=20) {printf("ERROR: unable to read to specified end line in header file\n"); exit(1);}
clock_drift_hist[hdr->clock_drift]++;
}
printf("APPLYING CLOCK DRIFT TO IMAGE TIMING.\n");
clock_drift_median = get_median(clock_drift_hist,MAX_CLOCK_DRIFT);
printf("\tclock_drift_median = %li \n",clock_drift_median);
clock_shift = (double) clock_drift_median / 1000.0;
start_sec += clock_shift;
if (start_sec > 86400.0) {start_sec -= 86400.0; start_date += 1;}
dtmp = date_hms2sec(&s_time)+clock_shift;
if (dtmp > 86400.0) { s_date.jd+=1; dtmp-=86400.0;}
date_sec2hms(dtmp,&s_time);
}
printf("Found start time: %i %i %lf\n",start_year, start_date, start_sec);
fclose(fp);
}
/***************************************************************
* 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;
}
/*Compute the date corresponding to this number of seconds
since midnight, Jan 1, 1900.
This is sub-millisecond accurate; but ignores leap seconds.
*/
void sec2date(double secs,julian_date *date,hms_time *time)
{
int year=1900;
while (secs>=date_getDaysInYear(year)*DAY2SEC)
secs-=date_getDaysInYear(year++)*DAY2SEC;
date->year=year;
date->jd=1+(int)(secs/DAY2SEC);
secs-=(date->jd-1)*DAY2SEC;
date_sec2hms(secs,time);
}
// Compute date corresponding to seconds since midnight, Jan 1, 1985.
void seconds2date(double seconds, ymd_date *date, hms_time *time)
{
julian_date jd;
int year = 1985;
double secs = seconds;
while (secs >= date_getDaysInYear(year)*DAY2SEC)
secs -= date_getDaysInYear(year++)*DAY2SEC;
jd.year = year;
jd.jd = 1 + (int)(secs/DAY2SEC);
secs -= (jd.jd - 1)*DAY2SEC;
date_sec2hms(secs, time);
date_jd2ymd(&jd, date);
}
static void rgps2iso_date(int year, double day, char *isoStr)
{
julian_date jd;
hms_time time;
ymd_date date;
jd.year = year;
jd.jd = (int) day;
date_jd2ymd(&jd, &date);
double sec = 86400 * (day - jd.jd);
date_sec2hms(sec, &time);
sprintf(isoStr, "%4d-%02d-%02dT%02d:%02d:%09.6lfZ",
date.year, date.month, date.day, time.hour, time.min, time.sec);
}
static void dateTimeStamp(meta_parameters *meta, int line,
iso_dateTime *dateTime)
{
julian_date jd;
hms_time hms;
ymd_date ymd;
jd.year = meta->state_vectors->year;
jd.jd = meta->state_vectors->julDay;
date_sec2hms(meta->state_vectors->second, &hms);
date_jd2ymd(&jd, &ymd);
double imgSec = line*meta->sar->azimuth_time_per_pixel;
add_time(imgSec, &ymd, &hms);
dateTime->year = ymd.year;
dateTime->month = ymd.month;
dateTime->day = ymd.day;
dateTime->hour = hms.hour;
dateTime->min = hms.min;
dateTime->second = hms.sec;
}
/*******************************************************
* meta_get_dop:
* Converts a line, sample pair to the doppler value at
* that location. Returns Hz. Only works for SR & GR. */
double meta_get_dop(meta_parameters *meta,double yLine, double xSample)
{
assert (meta->sar); // && (meta->sar->image_type == 'S'
// || meta->sar->image_type == 'G'));
yLine += meta->general->start_line;
xSample += meta->general->start_sample;
if (meta->doppler && meta->doppler->tsx) {
int ii;
julian_date imgStartDate, imgDopplerDate;
hms_time imgStartTime, imgDopplerTime;
double time, refTime, *coeff;
imgStartDate.year = meta->state_vectors->year;
imgStartDate.jd = meta->state_vectors->julDay;
date_sec2hms(meta->state_vectors->second, &imgStartTime);
imgDopplerDate.year = meta->doppler->tsx->year;
imgDopplerDate.jd = meta->doppler->tsx->julDay;
date_sec2hms(meta->doppler->tsx->second, &imgDopplerTime);
double imgAzimuthTime = date2sec(&imgStartDate, &imgStartTime) +
yLine * meta->sar->range_time_per_pixel;
double dopAzimuthStart = date2sec(&imgDopplerDate, &imgDopplerTime);
for (ii=0; ii<meta->doppler->tsx->doppler_count; ii++) {
time = dopAzimuthStart + meta->doppler->tsx->dop[ii].time;
if (time > imgAzimuthTime)
break;
}
int max = ii;
int min = ii - 1;
double dopAzimuthMin = dopAzimuthStart + meta->doppler->tsx->dop[min].time;
double dopRangeTimeMin = meta->doppler->tsx->dop[min].first_range_time +
xSample * meta->sar->azimuth_time_per_pixel;
refTime = meta->doppler->tsx->dop[min].reference_time;
coeff = (double *) MALLOC(sizeof(double)*
meta->doppler->tsx->dop[min].poly_degree);
double dopplerMin = 0.0;
for (ii=0; ii<=meta->doppler->tsx->dop[min].poly_degree; ii++) {
coeff[ii] = meta->doppler->tsx->dop[min].coefficient[ii];
dopplerMin += coeff[ii] * pow(dopRangeTimeMin - refTime, ii);
}
FREE(coeff);
double dopAzimuthMax = dopAzimuthStart + meta->doppler->tsx->dop[max].time;
refTime = meta->doppler->tsx->dop[min].reference_time;
coeff = (double *) MALLOC(sizeof(double)*
meta->doppler->tsx->dop[max].poly_degree);
double dopplerMax = 0.0;
for (ii=0; ii<=meta->doppler->tsx->dop[max].poly_degree; ii++) {
coeff[ii] = meta->doppler->tsx->dop[max].coefficient[ii];
dopplerMax += coeff[ii] * pow(dopRangeTimeMin - refTime, ii);
}
FREE(coeff);
return dopplerMin + (dopplerMax - dopplerMin) /
(dopAzimuthMax - dopAzimuthMin) * (imgAzimuthTime - dopAzimuthMin);
}
else if (meta->doppler && meta->doppler->r2) {
int ii;
double doppler = 0.0;
radarsat2_doppler_params *r2 = meta->doppler->r2;
double slant_time =
r2->time_first_sample + xSample * meta->sar->range_time_per_pixel;
for (ii=0; ii<r2->doppler_count; ++ii)
doppler +=
r2->centroid[ii] * pow((slant_time - r2->ref_time_centroid), ii);
return doppler;
}
else
return meta->sar->range_doppler_coefficients[0]+
meta->sar->range_doppler_coefficients[1]*xSample+
meta->sar->range_doppler_coefficients[2]*xSample*xSample+
meta->sar->azimuth_doppler_coefficients[1]*yLine+
meta->sar->azimuth_doppler_coefficients[2]*yLine*yLine;
}
meta_parameters* airsar2meta(airsar_header *header,
airsar_param_header *params,
airsar_dem_header *dem)
{
meta_parameters *meta;
hms_time hms;
// Allocate memory for metadata structure
meta = raw_init();
// General block
sprintf(meta->general->basename, "%s", params->site_name);
sprintf(meta->general->sensor, "AIRSAR");
strcpy(meta->general->sensor_name, "SAR");
if (strlen(header->processor)>0) {
header->processor[4] = '\0';
strcpy(meta->general->processor, "JPL version ");
strcat(meta->general->processor, header->processor);
} else {
strcpy(meta->general->processor, MAGIC_UNSET_STRING);
}
// FIXME: various data types - InSAR vs. polarimetric
date_sec2hms(params->acquisition_seconds, &hms);
sprintf(meta->general->acquisition_date, "%s %d:%d:%.3lf",
params->acquisition_date, hms.hour, hms.min, hms.sec);
meta->general->orbit = params->cct_id; // close enough
// no frame number
// FIXME: decide how to separate interferometric/polarimetric data
meta->general->band_count = 1;
meta->general->line_count = header->line_count;
//header->line_count - header->first_data_offset / header->sample_count;
meta->general->sample_count = header->sample_count;
meta->general->start_line = 0;
meta->general->start_sample = 0;
meta->general->x_pixel_size = header->x_pixel_size;
meta->general->y_pixel_size = header->y_pixel_size;
meta->general->center_latitude = params->center_lat;
meta->general->center_longitude = params->center_lon;
meta->general->re_major = 6378137.0; // WGS84
meta->general->re_minor = 6356752.314; // WGS84
// no information on bit error rate, missing lines and no data
// SAR block
meta->sar = meta_sar_init();
// The CCT type 'CM' stands for 'Compressed Stokes Matrix' which implies
// that you have fully polarimetric data
if (strncmp_case(params->cct_type, "CM", 2) == 0) {
meta->general->image_data_type = POLARIMETRIC_IMAGE;
meta->general->radiometry = r_SIGMA;
strcpy(meta->sar->polarization, "QUAD-POL");
meta->general->band_count = 8;
}
if (strncmp_case(header->range_projection, "GROUND", 6) == 0)
meta->sar->image_type = 'G';
// no information on look direction
if (params->deskewed == 1)
meta->sar->deskewed = 1;
else if (params->deskewed == 2)
meta->sar->deskewed = 0;
meta->sar->original_line_count = header->line_count;
meta->sar->original_sample_count = header->sample_count;
meta->sar->line_increment = 1;
meta->sar->sample_increment = 1;
// no information on azimuth and range time per pixel
// no information on slant and time shift
meta->sar->slant_range_first_pixel = params->near_slant_range;
meta->sar->wavelength = params->wavelength;
meta->sar->prf = params->prf;
// no information on earth radius and satellite height
// no time information
// no Doppler information
meta->sar->azimuth_processing_bandwidth = params->chirp_bandwidth;
// no chirp rate information
meta->sar->pulse_duration = params->pulse_length;
meta->sar->range_sampling_rate = params->range_sampling_rate;
// FIXME: check polarizations for interferometric/polarimetric data
// FIXME: multilook flag depends on data type
// AirSAR block
meta->airsar = meta_airsar_init();
meta->airsar->scale_factor = 1.0; // Bruce Chapman said so.
meta->airsar->gps_altitude = params->gps_altitude;
if (dem) {
meta->airsar->lat_peg_point = dem->lat_peg_point;
meta->airsar->lon_peg_point = dem->lon_peg_point;
meta->airsar->head_peg_point = dem->head_peg_point;
meta->airsar->along_track_offset = dem->along_track_offset;
meta->airsar->cross_track_offset = dem->cross_track_offset;
}
else {
meta->airsar->lat_peg_point = params->lat_peg_point;
meta->airsar->lon_peg_point = params->lon_peg_point;
meta->airsar->head_peg_point = params->head_peg_point;
meta->airsar->along_track_offset = params->along_track_offset;
meta->airsar->cross_track_offset = params->cross_track_offset;
}
// The DEM header of Rick's prime test data did not have a valid peg point.
// Without that the other numbers (along-track and cross-track offsets
// as well as corner coordinates) don't make sense.
// Will take the numbers out of the parameter header. Seems to work fine
// with the prime test data set. Extract only elevation offset and increment
// out of the DEM header
if (dem) {
meta->airsar->elevation_increment = dem->elevation_increment;
meta->airsar->elevation_offset = dem->elevation_offset;
}
// Location block
meta->location = meta_location_init();
if (dem) {
meta->location->lat_start_near_range = dem->corner1_lat;
meta->location->lon_start_near_range = dem->corner1_lon;
meta->location->lat_start_far_range = dem->corner2_lat;
meta->location->lon_start_far_range = dem->corner2_lon;
meta->location->lat_end_near_range = dem->corner4_lat;
meta->location->lon_end_near_range = dem->corner4_lon;
meta->location->lat_end_far_range = dem->corner3_lat;
meta->location->lon_end_far_range = dem->corner3_lon;
}
return meta;
}
/***************************************************************
* Ceos_init_stVec:
* Reads state vectors from given CEOS file, writing them in the
* appropriate format to SAR parameters structure.*/
void ceos_init_stVec(const char *fName, ceos_description *ceos,
meta_parameters *meta)
{
struct pos_data_rec ppdr;
/*Fetch platform position data record.*/
get_ppdr(fName,&ppdr);
// Read the state vectors from the leader data file, adjust coordinate system, etc.
// and write them to the SAR parameters structures
ceos_read_stVecs(fName, ceos, meta);
// For ALOS Palsar orbits only
// Don't propagate but select nine state vectors around the center for the
// higher order interpolation scheme
if (ceos->processor == ALOS_PROC) {
// Determine closest state vector
int ii, min;
double diff = 99999999;
for (ii=0; ii<meta->state_vectors->vector_count; ii++) {
if (fabs(meta->state_vectors->vecs[ii].time) < diff) {
diff = fabs(meta->state_vectors->vecs[ii].time);
min = ii;
}
}
// Populate a new state vector
ymd_date img_ymd;
julian_date img_jd;
hms_time img_time;
img_jd.year = meta->state_vectors->year;
img_jd.jd = meta->state_vectors->julDay;
date_sec2hms(meta->state_vectors->second,&img_time);
date_jd2ymd(&img_jd, &img_ymd);
add_time((min-4)*60, &img_ymd, &img_time);
date_ymd2jd(&img_ymd, &img_jd);
meta_state_vectors *new_st = meta_state_vectors_init(9);
new_st->year = img_jd.year;
new_st->julDay = img_jd.jd;
new_st->second = date_hms2sec(&img_time);
for (ii=0; ii<9; ii++)
new_st->vecs[ii] = meta->state_vectors->vecs[ii+min-4];
FREE(meta->state_vectors);
meta->state_vectors = new_st;
// Time shift should definitely set in the code that is calling this function
// meta->sar->time_shift = 0.0;
}
// Propagate three state vectors for regular frames
else if (ceos->processor != PREC && ceos->processor != unknownProcessor) {
int vector_count=3;
double data_int = meta->sar->original_line_count / 2
* fabs(meta->sar->azimuth_time_per_pixel);
meta->state_vectors->vecs[0].time = get_timeDelta(ceos, &ppdr, meta);
if (ceos->processor != PREC && data_int < 360.0) {
while (fabs(data_int) > 15.0) {
data_int /= 2;
vector_count = vector_count*2-1;
}
// propagate three state vectors: start, center, end
propagate_state(meta, vector_count, data_int);
}
}
}