void spkw10_c ( SpiceInt handle,
ConstSpiceChar * frame,
ConstSpiceChar * segid,
ConstSpiceDouble consts ,
ConstSpiceDouble elems ,
ConstSpiceDouble epochs  )
Write an SPK type 10 segment to the DAF open and attached to
the input handle.
VARIABLE I/O DESCRIPTION
-------- --- --------------------------------------------------
handle I The handle of a DAF file open for writing.
body I The NAIF ID code for the body of the segment.
center I The center of motion for body.
frame I The reference frame for this segment.
first I The first epoch for which the segment is valid.
last I The last epoch for which the segment is valid.
segid I The string to use for segment identifier.
consts I The array of geophysical constants for the segment
n I The number of element/epoch pairs to be stored
elems I The collection of "two-line" element sets.
epochs I The epochs associated with the element sets.
handle is the file handle of an SPK file that has been
opened for writing by spcopn, dafopn, or dafopw.
body is the NAIF ID for the body whose states are
to be recorded in an SPK file.
center is the NAIF ID for the center of motion associated
frame is the reference frame that states are referenced to,
for example "J2000".
first are the bounds on the ephemeris times, expressed as
last seconds past J2000, for which the states can be used
to interpolate a state for body.
segid is the segment identifier. An SPK segment identifier
may contain up to 40 characters.
consts are the geophysical constants needed for evaluation
of the two line elements sets. The order of these
constants must be:
consts = J2 gravitational harmonic for earth
consts = J3 gravitational harmonic for earth
consts = J4 gravitational harmonic for earth
consts = Square root of the GM for earth where GM
is expressed in earth radii cubed per
consts = Equatorial radius of the earth in km
consts = Low altitude bound for atmospheric
model in km
consts = High altitude bound for atmospheric
model in km
consts = Distance units/earth radius (normally 1)
n is the number of "two-line" element sets and epochs
to be stored in the segment.
elems contains a time-ordered array of two-line elements
as supplied in NORAD two-line element files. The
i'th set of elements (where i ranges from 1 to n)
should be stored as shown here:
base = (i-1)*10
elems ( base + 0 ) = NDT20
elems ( base + 1 ) = NDD60
elems ( base + 2 ) = BSTAR
elems ( base + 3 ) = INCL
elems ( base + 4 ) = NODE0
elems ( base + 5 ) = ECC
elems ( base + 6 ) = OMEGA
elems ( base + 7 ) = MO
elems ( base + 8 ) = NO
elems ( base + 9 ) = EPOCH
The meaning of these variables is defined by the
format of the two-line element files available from
epochs contains the epochs (ephemeris seconds past J2000)
corresponding to the elements in elems. The I'th
epoch must equal the epoch of the I'th element set
Epochs must form a strictly increasing sequence.
None. The data input is stored in an SPK segment in the
DAF connected to the input handle.
1) Errors in the structure or content of the inputs must be
diagnosed by routines called by this one.
2) File access errors are diagnosed by routines in the
call tree of this routine.
3) If either the input frame or segment ID string pointer is null,
the error SPICE(NULLPOINTER) is signaled.
4) If either the input frame or segment ID string is empty,
the error SPICE(EMPTYSTRING) is signaled.
This routine writes a type 10 SPK segment to the DAF open
for writing that is attached to handle. A routine, GETELM, that
reads two-line element data from files distributed by
NORAD is available from NAIF.
Suppose that you have collected the two-line element data
and geophysical constants as prescribed above. The following
code fragment demonstrates how you could go about creating
a type 10 SPK segment.
Open a new SPK file using DAF and get a file handle.
body = <integer code for the body>;
center = <integer code for central body for the trajectory>;
frame = "J2000";
segid = <string that gives the bodies name>;
fname = "SAMPLE.SPK";
ifname = "SAMPLE SPK FILE FOR PRIVATE USE";
ncomch = 0;
void spkopn_c ( fname, ifname, ncomch, &handle );
Add the type 10 data.
spkw10_c ( handle, body, center, frame, first, last,
segid, consts, n, elems, epochs );
Close the SPK properly.
spkcls_c ( handle );
N.J. Bachman (JPL)
W.L. Taber (JPL)
-CSPICE Version 1.0.1, 30-OCT-2006 (BVS)
Deleted "inertial" from the FRAME description in the Brief_I/O
section of the header.
-CSPICE Version 1.0.0, 29-JUN-1999 (NJB) (WLT)
write a type_10 spk segment