spkw09_c |

Table of contents## Procedurespkw09_c ( Write SPK segment, type 9 ) void spkw09_c ( SpiceInt handle, SpiceInt body, SpiceInt center, ConstSpiceChar * frame, SpiceDouble first, SpiceDouble last, ConstSpiceChar * segid, SpiceInt degree, SpiceInt n, ConstSpiceDouble states[][6], ConstSpiceDouble epochs[] ) ## AbstractWrite a type 9 segment to an SPK file. ## Required_ReadingNAIF_IDS SPC SPK TIME ## KeywordsEPHEMERIS FILES ## Brief_I/OVARIABLE I/O DESCRIPTION -------- --- -------------------------------------------------- handle I Handle of an SPK file open for writing. body I NAIF code for an ephemeris object. center I NAIF code for center of motion of body. frame I Reference frame name. first I Start time of interval covered by segment. last I End time of interval covered by segment. segid I Segment identifier. degree I Degree of interpolating polynomials. n I Number of states. states I Array of states. epochs I Array of epochs corresponding to states. maxdeg P Maximum allowed degree of interpolating polynomial. ## Detailed_Inputhandle is the file handle of an SPK file that has been opened for writing. body is the NAIF integer code for an ephemeris object whose state relative to another body is described by the segment to be created. center is the NAIF integer code for the center of motion of the object identified by body. frame is the NAIF name for a reference frame relative to which the state information for body is specified. first, last are, respectively, the start and stop times of the time interval over which the segment defines the state of body. segid is the segment identifier. An SPK segment identifier may contain up to 40 characters. degree is the degree of the Lagrange polynomials used to interpolate the states. All components of the state vectors are interpolated by polynomials of fixed degree. n is the number of states in the input state vector array. states contains a time-ordered array of geometric states (x, y, z, dx/dt, dy/dt, dz/dt, in kilometers and kilometers per second) of body relative to center, specified relative to frame. epochs is an array of epochs corresponding to the members of the state array. The epochs are specified as seconds past J2000, TDB. ## Detailed_OutputNone. See -Particulars for a description of the effect of this routine. ## ParametersMAXDEG is the maximum allowed degree of the interpolating polynomial. If the value of MAXDEG is increased, the CSPICE routine spkpvn_ must be changed accordingly. In particular, the size of the record passed to spkrNN_ and spkeNN_ must be increased, and comments describing the record size must be changed. The current value of MAXDEG is 15. ## ExceptionsIf any of the following exceptions occur, this routine will return without creating a new segment. 1) If `frame' is not a recognized name, the error SPICE(INVALIDREFFRAME) is signaled by a routine in the call tree of this routine. 2) If the last non-blank character of `segid' occurs past index 40, the error SPICE(SEGIDTOOLONG) is signaled by a routine in the call tree of this routine. 3) If `segid' contains any nonprintable characters, the error SPICE(NONPRINTABLECHARS) is signaled by a routine in the call tree of this routine. 4) If `degree' is not at least 1 or is greater than MAXDEG, the error SPICE(INVALIDDEGREE) is signaled by a routine in the call tree of this routine. 5) If the number of states `n' is not at least degree+1, the error SPICE(TOOFEWSTATES) is signaled by a routine in the call tree of this routine. 6) If `first' is greater than or equal to `last', the error SPICE(BADDESCRTIMES) is signaled by a routine in the call tree of this routine. 7) If the elements of the array `epochs' are not in strictly increasing order, the error SPICE(TIMESOUTOFORDER) is signaled by a routine in the call tree of this routine. 8) If the first epoch, epochs[0], is greater than `first', the error SPICE(BADDESCRTIMES) is signaled by a routine in the call tree of this routine. 9) If the last epoch, epochs[n-1], is less than `last', the error SPICE(BADDESCRTIMES) is signaled by a routine in the call tree of this routine. 10) If any of the `frame' or `segid' input string pointers is null, the error SPICE(NULLPOINTER) is signaled. 11) If any of the `frame' or `segid' input strings has zero length, the error SPICE(EMPTYSTRING) is signaled. ## FilesA new type 9 SPK segment is written to the SPK file attached to handle. ## ParticularsThis routine writes an SPK type 09 data segment to the open SPK file according to the format described in the type 09 section of the SPK Required Reading. The SPK file must have been opened with write access. ## ExamplesThe numerical results shown for this example may differ across platforms. The results depend on the SPICE kernels used as input, the compiler and supporting libraries, and the machine specific arithmetic implementation. 1) Suppose that you have a time-ordered array of geometric states of a new object that follows Phobos, with a delay of 1 hour, in its orbit around Mars and are prepared to produce a segment of type 09 in an SPK file. Create a new SPK file with this segment. Use an existing SPK to create the input data for the SPK segment. Use the meta-kernel shown below to load the required SPICE kernels. KPL/MK File: spkw09_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 --------- -------- mar097.bsp Mars satellite ephemeris naif0012.tls Leapseconds \begindata KERNELS_TO_LOAD = ( 'mar097.bsp', 'naif0012.tls' ) \begintext End of meta-kernel Example code begins here. /. Program spkw09_ex1 ./ #include <stdio.h> #include <math.h> #include "SpiceUsr.h" int main( ) { /. Local parameters. ./ #define SPKNAM "spkw09_ex1.bsp" #define DEGREE 3 #define MARS 499 #define NEPOCS 800 #define NOBJ 403 /. Local variables. ./ SpiceChar * ifname; SpiceChar * segid; SpiceDouble delta; SpiceDouble et; SpiceDouble epochs [NEPOCS]; SpiceDouble lt; SpiceDouble state [6]; SpiceDouble states [NEPOCS][6]; SpiceDouble step; SpiceDouble time; SpiceInt i; SpiceInt handle; /. Load the input SPK file. ./ furnsh_c ( "spkw09_ex1.tm" ); /. Convert the input UTC to ephemeris time ./ str2et_c ( "2018 Apr 03 08:35", &et ); /. Create the time-ordered array of geometric states, at unequal time steps. ./ time = et; step = 60.0; delta = 10.0; for ( i = 0; i < NEPOCS; i++ ) { spkezr_c ( "PHOBOS", time, "J2000", "NONE", "MARS", states[i], < ); epochs[i] = time + 3600.0; time = time + step + sin( halfpi_c ( ) * i / 2.0 ) * delta; } /. Open a new SPK file, with 5000 characters reserved for comments. ./ ifname = "Test SPK type 9 internal filename."; spkopn_c ( SPKNAM, ifname, 5000, &handle ); /. Create a segment identifier. ./ segid = "MY_SAMPLE_SPK_TYPE_9_SEGMENT"; /. Write the segment. ./ ## RestrictionsNone. ## Literature_ReferencesNone. ## Author_and_InstitutionN.J. Bachman (JPL) J. Diaz del Rio (ODC Space) K.R. Gehringer (JPL) J.M. Lynch (JPL) W.L. Taber (JPL) ## Version-CSPICE Version 1.0.1, 10-AUG-2021 (JDR) Edited the header to comply with NAIF standard. Added complete code example to the -Examples section. -CSPICE Version 1.0.0, 21-JUN-1999 (KRG) (NJB) (JML) (WLT) ## Index_Entrieswrite SPK type_9 ephemeris data segment |

Fri Dec 31 18:41:13 2021