#include <etx.h> int ettime(xfm, date, time) ETXFORM xfm; int *date; double *time; int etdata3(xfm, what, x, y, z) ETXFORM xfm; int what; double *x, *y, *z; int etgetadj(xfm, adj) ETXFORM xfm; double *adj; int etgetatt(xfm, roll, pitch, yaw) ETXFORM xfm; double *roll, *pitch, *yaw; int etgettilt(xfm, tilt) ETXFORM xfm; double *tilt; int etadjtim(xfm, adj) ETXFORM xfm; double adj; int etsetatt(xfm, roll, pitch, yaw) ETXFORM xfm; double roll, pitch, yaw; int etsettilt(xfm, tilt) ETXFORM xfm; double tilt;
The functions described here are used to get and set satellite- and sensor-related information relative to earth transforms.
ettime and etdata3 return information relative to the last call to sensorll or llsensor. sensorll and llsensor may be called indirectly as part of calling etxll and lletx when the earth transform projection is SENSOR_PROJ. See etxll.
ettime returns the date and time in TeraScan standard format for the current satellite position. etdata3 returns a variety of information, depending on the what option:
Unit geocentric vector to satellite
Unit geocentric vector to pixel
Unit geocentric vector to sun
Satellite roll, pitch, yaw (radians)
cos(sun zenith), cos(sun-pixel-sat), cos(sat zenith)
Satellite inertial velocity (radians/sec)
Satellite inertial accel (radians/sec**2)
Satellite orbital velocity (radians/sec)
Satellite orbital accel (radians/sec**2)
sensor scan rates measured in lines/sec, samples/sec, radians/sec
Satellite orbital radius, satellite to pixel, pixel to subtrack (radians)
These options are found in include/etx.h. Note that the radius of the geocentric earth is 1 if measured in radians. Zenith angles are measured from vertical; a sun zenith angle of 0 means the sun is directly overhead.
etgetadj, etgetatt, and etgettilt, return the current values for satellite clock adjustment, satellite attitude, and sensor tilt. CZCS is really the only sensor for which sensor tilt is relevant. Time adjustment is measured in seconds. Satellite attitude and sensor tilt angles are measured in degrees.
Similarly, etsetadj, etsetatt, and etsettilt change the current values for satellite clock adjustment, satellite attitude, and sensor tilt for the earth transform encoded in xfm. Changes are not saved to disk unless etstore is called. See etready.
All of the above functions return 0 if successful. Otherwise, they return -1 and set terrno to the appropriate error code. Error codes are listed in include/etx.h.
None of these routines checks if earth transform encoded in xfm supports satellite and sensor calculations.
Bad option passed to etdata3.
include/etx.h, include/terrno.h, lib/libetx.a
etcoords, etmisc, etnames, etready, etxll etx
None.
Last Update: $Date: 2001/05/16 22:51:31 $