This function writes, in sequential mode, a type 2 segment (Chebyshev polynomials of Chebyshev polynomials of the positions only) to the SPK file associated to the ephemeris descriptor eph.

The polynomials array must be of size record_count*(deg+1)*3 and have the following structure :

X's 1st coef 1st record	...	X's (deg + 1)th coef 1st record	Y's 1st coef 1st record	...	Y's (deg + 1)th coef 1st record	Z's 1st coef 1st record	...	Z's (deg + 1)th coef 1st record
...	...	...	...	...	...	...	...	...
X's 1st coef (record_count)th record	...	X's (deg + 1)th coef (record_count)th record	Y's 1st coef (record_count)th record	...	Y's (deg + 1)th coef (record_count)th record	Z's 1st coef (record_count)th record	...	Z's (deg + 1)th coef (record_count)th record

The following example creates a new ephemeris file ephemeris.bsp with segment of type 2 for the heliocentric coordinates of Venus.

t_writephbin *weph;
const char segid[] = "seg_planet";

weph = writeph_spk_create("ephemeris.bsp","planet_2");
if (weph)
{
      int len_timespan = 32; /* days */
      int frame = 1; /* ICRF */
      int record_count = 10;
      int degree = 12;
      double jd_start = 2460000;
      double jd_end = jd_start+record_count*len_timespan;
      double coefs[390];  /*  size = 10*13*3  = record_count * (degree+1) * 3 components */

      for (int k=0; k<record_count; k++)
      {

           double jd_startk = jd_start+k*len_timespan;
           double jd_endk = jd_start+(k+1)*len_timespan;


           /* ... fill the array coefs with the coefficients of the Chebychev polynomials ...
                coefs[..] =...
           */
      }
      writeph_spk2_seq_write(weph, NAIFID_VENUS, NAIFID_SUN, frame, jd_start, 0.0, jd_end, 0.0,
                             len_timespan, coefs, record_count, degree+1, segid);


      writeph_close(weph);
}