Table of contents
CSPICE_SCE2S converts an epoch specified as ephemeris seconds
past J2000 (ET) value describing a date to a character string
representation of a spacecraft clock value (SCLK).
Given:
sc the NAIF ID of the spacecraft clock whose encoded SCLK value
at the epoch `et' is desired.
[1,1] = size(sc); int32 = class(sc)
et the ephemeris time(s) expressed as ephemeris seconds
past J2000.
[1,n] = size(et); double = class(et)
the call:
[sclkch] = cspice_sce2s( sc, et )
returns:
sclkch the representation(s) of spacecraft `sc' clock count that
corresponds to `et'.
[n,c1] = size(sclkch); char = class(sclkch)
'sclkch' returns with the same vectorization measure (N)
as 'et'.
None.
Any numerical results shown for this example may differ between
platforms as the results depend on the SPICE kernels used as input
and the machine specific arithmetic implementation.
1) Convert a series of UTC times to the character string
representation of the CASSINI spacecraft clock values.
Use the meta-kernel shown below to load the required SPICE
kernels.
KPL/MK
File name: sce2s_ex1.tm
This meta-kernel is intended to support operation of SPICE
example programs. The kernels shown here should not be
assumed to contain adequate or correct versions of data
required by SPICE-based user applications.
In order for an application to use this meta-kernel, the
kernels referenced here must be present in the user's
current working directory.
The names and contents of the kernels referenced
by this meta-kernel are as follows:
File name Contents
--------- ------------
naif0012.tls Leapseconds
cas00071.tsc CASSINI SCLK
\begindata
KERNELS_TO_LOAD = ( 'naif0012.tls',
'cas00071.tsc' )
\begintext
End of meta-kernel
Example code begins here.
function sce2s_ex1()
%
% Load kernels.
%
cspice_furnsh( 'sce2s_ex1.tm' )
%
% Assign values for the spacecraft ID (CASSINI).
%
SC = -82;
event_time = '2004 JUN 11 11:00:37.57200';
%
% Convert the time string to ephemeris time.
%
et = cspice_str2et( event_time );
%
% Convert the ephemeris time to the corresponding
% SCLK string appropriate for this spacecraft
%
sclkch = cspice_sce2s( SC, et );
disp( ' UTC Time SCLK string' )
disp( '-------------------------- ----------------' )
disp( 'Scalar:' )
txt = sprintf( '%s %s', event_time, sclkch );
disp( txt )
%
% Vectorized use, a vector of UTC times.
%
event_time = strvcat( '2004 JUN 11 12:00:37.57200', ...
'2004 JUN 11 13:00:37.57200', ...
'2004 JUN 11 14:00:37.57200' );
%
% Convert the time strings to ET.
%
et = cspice_str2et( event_time );
%
% Convert the ephemeris time to the corresponding
% SCLK string appropriate for this spacecraft
%
sclkch = cspice_sce2s( SC, et );
disp( 'Vector:' )
for i=1:3
txt = sprintf( '%s %s', event_time(i,:), sclkch(i,:));
disp( txt )
end
%
% It's always good form to unload kernels after use,
% particularly in MATLAB due to data persistence.
%
cspice_kclear
When this program was executed on a Mac/Intel/Octave6.x/64-bit
platform, the output was:
UTC Time SCLK string
-------------------------- ----------------
Scalar:
2004 JUN 11 11:00:37.57200 1/1465644305.079
Vector:
2004 JUN 11 12:00:37.57200 1/1465647905.085
2004 JUN 11 13:00:37.57200 1/1465651505.092
2004 JUN 11 14:00:37.57200 1/1465655105.098
This routine is provided as a convenience; it is simply shorthand
for the code fragment
[sclkdp] = cspice_sce2t( sc, et );
[sclkch] = cspice_scdecd( sc, sclkdp );
1) If an SCLK kernel has not been loaded, does not contain all of
the required data, or contains invalid data, an error is
signaled by a routine in the call tree of this routine. The
output argument `sclkch' will not be modified. This routine
assumes that an SCLK kernel appropriate to the spacecraft
clock identified by the input argument `sc' has been loaded.
2) If a leapseconds kernel is required for conversion between
SCLK and `et' but is not loaded, an error is signaled by a
routine in the call tree of this routine. The output argument
`sclkch' will not be modified. When using an SCLK kernel that
maps SCLK to a time system other than `et' (also called
barycentric dynamical time---`TDB'), it is necessary to have a
leapseconds kernel loaded at the time this routine is called.
The time system to which an SCLK kernel maps SCLK epochs is
indicated by the variable SCLK_TIME_SYSTEM_nn in the kernel,
where nn is the negative of the NAIF integer code for the
spacecraft. The time system used in a kernel is TDB if and
only if the variable is assigned the value 1.
3) If the input `et' value is not representable in the spacecraft
clock string format for the spacecraft clock identified by `sc',
an error is signaled by a routine in the call tree of this
routine. The output argument `sclkch' will not be modified.
4) If any of the input arguments, `sc' or `et', is undefined, an
error is signaled by the Matlab error handling system.
5) If any of the input arguments, `sc' or `et', is not of the
expected type, or it does not have the expected dimensions and
size, an error is signaled by the Mice interface.
An SCLK kernel, appropriate to the spacecraft clock identified
by `sc', must be loaded at the time this routine is called.
If the SCLK kernel used with this routine does not map SCLK
directly to barycentric dynamical time, a leapseconds kernel
must be loaded at the time this routine is called.
None.
MICE.REQ
SCLK.REQ
TIME.REQ
None.
J. Diaz del Rio (ODC Space)
E.D. Wright (JPL)
-Mice Version 1.1.0, 10-AUG-2021 (EDW) (JDR)
Edited the -Examples section to comply with NAIF standard. Added
example's problem statement and meta-kernel with CASSINI PDS
archived data. Reformatted code example output.
Added -Parameters, -Exceptions, -Files, -Restrictions,
-Literature_References and -Author_and_Institution sections, and
completed -Particulars section.
Removed reference to the function's corresponding CSPICE header from
-Required_Reading section.
-Mice Version 1.0.1, 06-JAN-2015 (EDW)
Edited -I/O section to conform to NAIF standard for Mice
documentation.
-Mice Version 1.0.0, 18-APR-2006 (EDW)
ephemeris time to spacecraft_clock string
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