Index Page

MKSPK User's Guide

   MKSPK User's Guide
      Abstract
      Summary
      Usage
      Execution of MKSPK
      Setup File Format and Contents
         Required Assignments
         Conditional Assignments
         Optional Assignments
      Detailed Description of Setup File Keywords
      Description of Input Data Format
      Description of Input Data Parameters
      Description of Input Data Types and Content
         Input Type STATES
         Input Type ELEMENTS
         Input Type EQ_ELEMENTS
         Input Type TL_ELEMENTS
      Relation Between Number of Input Records and Output Types
      Examples of Input Data and Setup Files
         Data Order and Data Delimiters
         Example 1
         Example 2
         Example 3
         Example 4
      Using Time Wrappers
      Complete Examples
         Input Data Type STATES / Output SPK Type 05
         Input Data Type STATES / Output SPK Type 08
         Input Data Type STATES / Output SPK Type 09
         Input Data Type STATES / Output SPK Type 12
         Input Data Type STATES / Output SPK Type 13
         Input Data Type STATES / Output SPK Type 15
         Input Data Type STATES / Output SPK Type 17
         Input Data Type ELEMENTS / Output SPK Type 05
         Input Data Type ELEMENTS / Output SPK Type 08
         Input Data Type ELEMENTS / Output SPK Type 09
         Input Data Type ELEMENTS / Output SPK Type 12
         Input Data Type ELEMENTS / Output SPK Type 13
         Input Data Type ELEMENTS / Output SPK Type 15
         Input Data Type ELEMENTS / Output SPK Type 17
         Input Data Type EQ_ELEMENTS / Output SPK Type 17
         Input Data Type TL_ELEMENTS / Output SPK Type 10
         Skipping Input Data Record Tokens
         Two Epochs in the Input Data Records

MKSPK User's Guide

Last revised on 2010 JUN 03 by B. V. Semenov.

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Abstract

MKSPK is a program that creates an SPK file from a text file containing trajectory information.

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Summary

MKSPK is a NAIF Toolkit utility program that generates a new, or appends data to an existing, spacecraft or target body's ephemeris file in SPICE SPK format using one of the following SPK types: 5, 8, 9, 10, 12, 13, 15, 17. This SPK file is a binary file constructed according to the SPICE DAF (Double Precision Array File) architecture, containing one or more SPK data segments.

The MKSPK program accepts one ASCII text file containing descriptions of input data (setup file) and a second ASCII text file (input file) containing the source ephemeris data to be processed.

Source ephemeris data can be time ordered lists of states (positions and velocities), sets of conic elements, sets of two-line elements, or a single set of equinoctial elements. All input data must be defined in a reference frame and relative to a body center both of which are specified in the setup file.

The program allows the user to optionally specify some descriptive text in a separate file (comment file) to be placed into the ``comment area'' of the SPK ephemeris file. (Doing this is highly recommended.)

For archival documentation purposes the content of the MKSPK setup file is automatically placed at the end of the ``comment area'' of the SPK file.

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Usage

Program usage:

      > mkspk [-setup <setup file name>]
              [-input <input data file name>]
              [-output <output SPK file name>]
              [-append]
              [-u|-usage]
              [-h|-help]
              [-t|-template] [<input data type> <output spk type>]

If a setup file name isn't provided on the command line, the program will prompt for it. It will not prompt for the input or output file names -- these must be provided on the command line or in the setup file. If input and output file names are provided on the command line, any file names assigned using setup keywords are ignored.

The input file must already exist.

If the -append key or the corresponding setup file keyword is not specified, the output file must not exist prior to running the program.

If the -append key or the corresponding setup file keyword is provided and the SPK file specified after the -output key exists, then new data will be appended to it.

If the -append key or the corresponding setup file keyword is provided but the SPK file specified after the -output key doesn't exist, then a new SPK file with the name specified after -output key will be created.

Caution: if the program fails for any reason, it, in most cases, deletes the output file, even if it was appending data to an existing SPK file. Therefore, users should always make a backup copy of an SPK file to which new data is going to be appended before running the program in append mode.

Also, the program cannot append data to an existing SPK file if its format is not native to the platform on which the program is running. Refer to the CONVERT User's Guide (convert.ug) for details.

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Execution of MKSPK

You will need a setup file to execute the MKSPK utility program. The format for the setup file is described below.

As it executes, the program will display a brief summary of its action.

Only one SPK ephemeris file using a single SPK type and containing one or more segments may be generated during a single MKSPK session.

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Setup File Format and Contents

Other than the input and output file names, which may occur on the command line, the program requires all inputs such as object and body names or ID, frame name or ID, types of input and output data, list and order of input parameters, constants, etc. to be provided in a setup file. The format of this file must conform to the SPICE text kernel specification since the data from the setup file will be loaded into a kernel pool. This means that input values must be assigned to keyword variables using the format

      KEYWORD = VALUE

Each assignment is restricted to a single line. Sets of these assignments must be enclosed between

      \begindata
      \begintext

tokens, each of which must also be placed on a line by itself. Free-form descriptive/explanatory text may occur after the

      \begintext

token. Still more assignments could follow another

      \begindata

token.

The names of the setup file keywords must be strictly uppercase while the standard value of keywords may be upper, lower or mixed case. Any white space preceding or following keyword names, values and equal sign is ignored.

All character string values and time strings must be enclosed in single quotes, provided on a single line and be no longer than 80 characters. When multiple value are allowed and used, enclose the complete set in the "()" characters: KEYWORD = ( 'value1' 'value2' 'value3' ... )

All assignments are either required, conditional or optional as described below.

A setup file may contain blank lines. Non-printing characters including TAB should not be used in setup file lines containing keyword assignments or blank lines separating them within the data sections of a setup file. The program may not be able to parse correctly any of the setup file lines that contain non-printing characters and will signal a setup file parsing error on some computer platforms.

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Required Assignments

The following assignments must be present in a setup file:

      INPUT_DATA_TYPE   = 'STATES' or 'ELEMENTS' or 'EQ_ELEMENTS'
                          or 'TL_ELEMENTS'
      OUTPUT_SPK_TYPE   = 5 or 8 or 9 or 10 or 12 or 13 or 15 or 17
 
      OBJECT_ID         = Numeric code assigned to the object, or
                          NORAD s/c code ('TL_ELEMENTS'/SPK 10 only)
        or
      OBJECT_NAME       = 'NAIF supported object name'
 
      CENTER_ID         = Numeric code assigned to the body which
                          is the center of the motion for the object
        or
      CENTER_NAME       = 'NAIF supported body name'
 
      REF_FRAME_NAME    = 'reference frame name'
      PRODUCER_ID       = 'producer identifier'
      DATA_ORDER        = 'ordered list of input parameter names'
      DATA_DELIMITER    = 'delimiter separating input data items'
      LEAPSECONDS_FILE  = 'leapseconds file name'

The following assignments are required in the setup file if their values are not provided on the command line:

      INPUT_DATA_FILE   = 'input data file name'
      OUTPUT_SPK_FILE   = 'output SPK file name'

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Conditional Assignments

One or more of the following assignments may be needed depending on the kind of input data being used and other conditions. See the definitions that follow for details.

      PCK_FILE          = ( 'PCK_1 file name'
                            'PCK_2 file name'
                              ...
                            'PCK_n file name' )
      FRAME_DEF_FILE    = 'frame definition file name'
      COMMENT_FILE      = 'comment file name'
      INPUT_DATA_UNITS  = ( 'ANGLES = angle unit'
                            'DISTANCES= distance unit' )
      EPOCH_STR_LENGTH  = length of epoch string
      IGNORE_FIRST_LINE = number of initial lines to be ignored while
                          reading input file
      LINES_PER_RECORD  = number of lines in one input record
      TIME_WRAPPER      = '# time wrapper'
      START_TIME        = 'start time'
      STOP_TIME         = 'stop time'
      PRECESSION_TYPE   = 'NO PRECESSION' or
                          'APSIDE PRECESSION ONLY' or
                          'NODE PRECESSION ONLY' or
                          'APSIDE AND NODE PRECESSION'
      POLYNOM_DEGREE    = polynomial degree of Lagrange or Hermite
                          interpolation
      CENTER_GM         = center GM value
      CENTER_POLE_RA    = the right ascension of the center's north
                          pole given with respect to the reference
                          frame
      CENTER_POLE_DEC   = the declination of the center's north pole
                          given with respect to the reference frame
      CENTER_J2         = center's J2 value
      CENTER_EQ_RADIUS  = center's equatorial radius

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Optional Assignments

      SEGMENT_ID        = 'segment identifier'
      APPEND_TO_OUTPUT  = flag indicating whether new segments should
                          or shouldn't be appended to an existing SPK
                          file

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Detailed Description of Setup File Keywords

INPUT_DATA_TYPE: type of input data. Only one of four allowed values may be used as shown above.

OUTPUT_SPK_TYPE: type of output SPK file. Only one of eight allowed values may be used as shown above.

OBJECT_ID: object identifier.

: For all input data type/output SPK type combinations except 'TL_ELEMENTS'/SPK 10 (called 'TL_ELEMENTS'/SPK 10 case elsewhere in the text) this is ideally a NAIF reserved code of the object (which for spacecraft or other vehicles must be a negative number); if this keyword is absent the OBJECT_NAME keyword must be used.

: If NAIF has not assigned an ID code (based on DSN/GSFC assignments) the user may select a temporary ID, avoiding the range of -0 through -512. (It might be useful to contact NAIF for assignment of a temporary code.)

: For 'TL_ELEMENTS'/SPK 10 case this is the NORAD spacecraft code. Because the NAIF ID for a spacecraft must be a negative number while the NORAD ID is a positive number, the spacecraft ID that will appear in the output SPK file is constructed from the NORAD ID using the following rule:

                                 NAIF_ID = -100000 - NORAD_ID

OBJECT_NAME: name of the object. This is one of the NAIF supported names for the object. This keyword is required if the OBJECT_ID keyword is absent. If both keywords are present, the MKSPK program uses the OBJECT_ID and ignores this assignment.

CENTER_ID: center identifier. This is the NAIF reserved code of the center of motion for the object. If this keyword is absent, the CENTER_NAME keyword must be used. For the 'TL_ELEMENTS'/SPK 10 case this keyword must have the value 399 (NAIF ID for Earth mass center.)

CENTER_NAME: name of the center. This is one if the NAIF supported names for the center of motion. This keyword is required if the CENTER_ID keyword is absent. If both keywords are present the MKSPK program uses the CENTER_ID and ignores this assignment. If this keyword is provided for the 'TL_ELEMENTS'/SPK 10 case, it must have the value 'Earth'.

REF_FRAME_NAME: name of the reference frame. If this is not a standard frame supported by NAIF, the definition for this frame must be present in a frame definitions kernel file specified in the FRAME_DEF_FILE keyword. For the 'TL_ELEMENTS'/SPK 10 case this keyword must have the value 'J2000'.

PRODUCER_ID: producer identifier. This is a name identifying the producer of this SPK file. This value will appear in the comment area of the SPK.

DATA_ORDER: ordered list of input parameter names as they appear in the input data records. The names are delimited with white space.

DATA_DELIMITER: delimiter used to separate data items. This is picked from the following set: 'TAB' , 'EOL' , comma (',') , semicolon (';') or white space (' '). Only one of these values can be used. If your data does not use one of these delimiters the data must be modified before being processed through MKSPK.

LEAPSECONDS_FILE: leapseconds file name. This is the SPICE LSK file name, including full or relative path specification.

INPUT_DATA_FILE: input data file name. This keyword must be used if the input data file name is not provided on the command line. Include path if needed.

OUTPUT_SPK_FILE: output data file name. This keyword must be used if the output SPK file name is not provided on the command line. Include path if needed.

PCK_FILE: SPICE Planetary Constants file name. One or more files can be used. This keyword may be absent in the case when you do not need PCK constants or when these constants are defined with other setup keywords. Include path(s) if needed. For the 'TL_ELEMENTS'/SPK 10 case a PCK file containing Earth geophysical constants must be provided using this keyword.

FRAME_DEF_FILE: frame definition file name. This keyword is required if the reference frame specified in the REF_FRAME_NAME keyword is not one defined in SPICE Toolkit Software. In this case the frame must be defined in a frames definition kernel file. Include path if needed.

COMMENT_FILE: comment file name. This keyword is used if you want to include comments provided in this file in the comment area of the SPK file. Include path if needed.

INPUT_DATA_UNITS: angle and distance units. The values of this keyword define the units used for angles and distances appearing in the input data if these are not RADIANS or KM. All angle and distance units supported by SPICE may be used. The value fields take the form of an assignment, such as 'ANGLES=DEGREES' and 'DISTANCES=NAUTICAL_MILES'. The complete list of angle and distance units that are recognized by MKSPK is:

                                 RADIANS
                                 DEGREES        ARCMINUTES
                                 ARCSECONDS     HOURANGLE
                                 MINUTEANGLE    SECONDANGLE
 
                                 METERS         KM
                                 CM             MM
                                 FEET           INCHES
                                 YARDS          STATUTE_MILES
                                 NAUTICAL_MILES AU
                                 PARSECS        LIGHTSECS
                                 LIGHTYEARS

: Note that MKSPK assumes that the time units of any input data parameters or constants specified in the setup file are seconds.

EPOCH_STR_LENGTH: length (number of characters, including white space) of input data record epoch strings, from the first through the last non blank character. This length must be provided to the program in order to enable parsing of the input data records containing two epoch strings and using data delimiter characters which are also allowed in SPICE time strings -- white space (' ') or comma (',').

IGNORE_FIRST_LINE: number of lines to be ignored at the beginning of the input file. If this keyword is absent, the program starts data processing from the first line of the input file.

LINES_PER_RECORD: number of lines in each input record. This keyword must be present if EPOCH_STR_LENGTH is absent and the data delimiter is one also allowed in SPICE time strings -- white space (' ') or comma (',').

TIME_WRAPPER: the specification of alphanumeric characters that are used to either complete and/or further define the "EPOCH" strings (and the "EPOCHP" string, if this is also used) provided in the input data and processed by the program using the SPICE's time conversion routine STR2ET . Such characters may be added at the front (prefix), the end (suffix), or both of the epoch (and epochp, if used) data items. The location of the epoch (and epochp) data relative to prefix or suffix characters is specified with the

"#"

: character. As example,

                                 TIME_WRAPPER = '# TDT'

: would add the characters ' TDT' to the end of every epoch value (and to the epochp value, if present).

: If the "EPOCH" (and "EPOCHP") time tags are provided as ET seconds past J2000 this keyword must be set to the following special value:

                                 TIME_WRAPPER = '# ETSECONDS'

: See "Using Time Wrappers" later in this document for more details.

START_TIME: start time. This keyword defines the first valid epoch of the output SPK file. This value is always required for output SPK Types 15 and 17. If this value is absent for other output types, the MKSPK program calculates it using input data. This keyword does not apply when making 'TL_ELEMENTS'/SPK 10 SPK files. For these files the output SPK coverage start time is automatically set to be 12 hours before the time of the first input two-line elements set.

STOP_TIME: stop time. This keyword defines the last valid epoch of the output SPK file. This value is always required for output SPK Types 15 and 17. If this value is absent for other output types, the MKSPK program calculates it using input data. This keyword does not apply when making 'TL_ELEMENTS'/SPK 10 SPK files. For these files the output SPK coverage stop time is automatically set to be 12 hours after the time of the last input two-line elements set.

PRECESSION_TYPE: J2 processing flag for output type 15. Only one of four values may be specified using this keyword: 'NO PRECESSION', 'APSIDE PRECESSION ONLY', 'NODE PRECESSION ONLY', 'APSIDE AND NODE PRECESSION'

POLYNOM_DEGREE: polynomial degree of Lagrange interpolation for output SPK Type 8 or 9, or polynomial degree of Hermite interpolation for output SPK type 12 or 13. The polynomial degree of Hermite interpolation must be an odd number. Also, to ensure continuity of the polynomials over the time span covered by an SPK segment the degree for SPK types 8 and 9 should be odd while the degree for SPK types 12 and 13 should be equivalent to 3 mod 4 (3, 7, 11, etc.)

CENTER_GM: center GM. This keyword specifies the GM of the central body. If it is absent, the MKSPK program attempts to find this value in a PCK file. You do not need this keyword when input type is STATE and output type is 8, 9, 12 or 13 and when input type is EQ_ELEMENTS and output type is 17.

CENTER_POLE_RA: the right ascension of the central body's north pole. This keyword is used for output types 15 and 17. If it is absent, the MKSPK program attempts to compute this value using loaded PCK constants. The value must in units specified in the keyword INPUT_DATA_UNITS and with respect to the frame specified in the keyword REF_FRAME_NAME.

CENTER_POLE_DEC: the declination of the central body's north pole. This keyword is used for output types 15 and 17. If it is absent, the MKSPK program attempts to compute this value using loaded PCK constants. The value must in units specified in the keyword INPUT_DATA_UNITS and with respect to the frame specified in the keyword REF_FRAME_NAME.

CENTER_J2: central body's J2 coefficient. This keyword is needed only for output type 15. If it is absent, the MKSPK program attempts to find its value in a PCK file.

CENTER_EQ_RADIUS: equatorial radius of central body. This keyword is needed only for output type 15. If it is absent, the MKSPK program attempts to find its value in a PCK file.

SEGMENT_ID: segment identifier. The value assigned to this keyword can be up to 40 characters long. If this keyword is absent, the MKSPK program will use the first 40 characters on the INPUT_FILE_NAME value as the segment identifier.

APPEND_TO_OUTPUT: optional flag specifying whether it's permitted to append new segments to an existing SPK file. This keyword can have one of these two values: 'YES' if segments can be appended and 'NO' if appending segments is not permitted. If this keyword is not present, the program assumes the value 'NO'. An -append flag specified on the command line overrides either value of this keyword.

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Description of Input Data Format

MKSPK requires the input data file to be an ASCII text file containing states, conic elements or equinoctial elements, or Space Command two-line elements. Any two-line elements file has fixed format and is processed as a special case; an input file containing any other type of input data must comply with the rules described in this section and the section immediately following it.

All lines in the input file, including the last line, must be terminated with the line terminators native to the computer platform on which the program is run. If the lines are terminated with a non-native terminator, the program will not be able to process the input file correctly. If the last line of the input file is not terminated with the proper line terminator, the program will ignore it causing the data written to the output SPK file be incomplete.

The input file must contain a number of data records sufficient to generate an SPK file of a specified type (see subsection below). Each of the records must occupy the same number of non-blank lines and contain the same set of input data items, provided in the same order. Blank lines can appear anywhere between non-blank record lines and are not taken into account by the program.

The data set contained in each record must correspond to a single epoch. Data records in an input file must be provided in strictly increasing time order based on the values of the data item EPOCH. Data records with duplicate EPOCHs are not allowed.

An input file may also contain one or more initial lines that do not represent a valid data record (for example a table header). These lines can be ignored by specifying their count in the IGNORE_FIRST_LINE setup file keyword.

The order of the data items in each input data record must be specified in the DATA_ORDER keyword.

Input data items within each data record must be separated by one of the following delimiters:

      'TAB' or  'EOL' or  ';' or  ','  or  ' '

The delimiter is not required but is permitted after the last data item on a line. Any spaces between the delimiter and preceding or following data items are ignored. In the case when white space is used as the delimiter, multiple spaces between data items are treated as a single space.

If tabulation ('TAB'), end-of-line ('EOL') or semicolon (';') is used as the data delimiter then only two setup file keywords are required for MKSPK in order to parse input data -- DATA_ORDER and DATA_DELIMITER.

If comma (',') or white space (' '), which are also allowed in SPICE time strings, is used as the data delimiter and the input data records contain only one time parameter (EPOCH), then the number of lines in each input data record must be specified using the setup file keyword LINES_PER_RECORD. The DATA_ORDER and DATA_DELIMITER keywords must also be used.

If comma (',') or white space (' ') is used as the data delimiter and the input data records contain two times (EPOCH and EPOCHP), then both input times must have the same width, from the first though the last non-blank character, and this width must be specified in the setup file keyword EPOCH_STR_LENGTH. The DATA_ORDER and DATA_DELIMITER keywords must also be used.

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Description of Input Data Parameters

The MKSPK program gains considerable flexibility by accepting several forms of ephemeris information and epochs. Further flexibility is achieved by allowing the user to tell MKSPK how those input data are organized, and, by allowing the user to clearly identify the time system and format used for time tags (epochs).

Listed below are the names of all the input data known to MKSPK--you would use just a subset of these in any one MKSPK session. How you use these parameter names to tell MKSPK what kind of input data are to be processed is described below. Note that one parameter name, "SKIP", is used to indicate that some item(s) in your input data file are to be ignored by MKSPK.

EPOCH: epoch of the data, given in any time format allowed by the SPICE's time conversion routine STR2ET (for details, see section ``STR2ET'' of the Time Required Reading document, time.req) or as a DP number representing ET seconds past J2000. Note that the setup file keyword TIME_WRAPPER, which is optionally used to modify input times processed by STR2ET, must be set to the value

                      '# ETSECONDS'

: to process times given as ET seconds past J2000. This keyword is described below in the section ``Using Time Wrappers.''

X: X position coordinate of state vector

Y: Y position coordinate of state vector

Z: Z position coordinate of state vector

VX: X velocity coordinate of state vector

VY: Y velocity coordinate of state vector

VZ: Z velocity coordinate of state vector

A: semi-major axis

E: eccentricity

RP: radius of periapsis

T: orbital period

P: semi-latus rectum

INC: inclination

PER: argument of periapsis

NOD: longitude of ascending node

MEAN: mean anomaly

EXAN: eccentric anomaly

TRAN: true anomaly

EPOCHP: epoch of periapsis, given in any time format allowed by the SPICE's time conversion routine STR2ET (for details, see section ``STR2ET'' of the Time Required Reading document, time.req) or as a DP number representing ET seconds past J2000. Note that the setup file keyword TIME_WRAPPER, which is optionally be used to modify input periapsis times processed by STR2ET, must be set to the value

                      '# ETSECONDS'

: to process times given as ET seconds past J2000. This keyword is described below in the section ``Using Time Wrappers.''

TAU: time interval between EPOCH and periapsis (EPOCH-EPOCHP) in seconds

EQ_A: 1-st equinoctial element. This is the semi-major axis of the orbit

EQ_H: 2-nd equinoctial element. This is the value of (E*SIN(PER+NOD)) at the specified epoch.

EQ_K: 3-rd equinoctial element. This is the value of (E*COS(PER+NOD)) at the specified epoch

EQ_ML: 4-th equinoctial element. This is the mean longitude (MEAN+PER+NOD) at the specified epoch

EQ_P: 5-th equinoctial element. This is the value of (TAN(INC/2)*SIN(NOD)) at the specified epoch

EQ_Q: 6-th equinoctial element. This is the value of (TAN(INC/2)*COS(NODE)) at the specified epoch

DPER/DT: 7-th equinoctial element. This is the rate of the longitude of periapsis (dPER/dt) at the specified epoch

DMPN/DT: 8-th equinoctial element. This is the derivative of the mean longitude (dM/dt + dPER/dt + dNOD/dt) at the specified epoch.

DNOD/DT: 9-th equinoctial element. This is the rate of the longitude of the ascending node (dNOD/dt) at the specified epoch

SKIP: input data record parameter to be ignored. This parameter is used to identify the location in the input data records of any data items, or parts of a data item if a complete data item includes the delimiter within its value, that are not needed by MKSPK and therefore should be ignored. This string may be used as many times as needed. Note that sometimes more than one SKIP may be needed to ignore an additional time tag in an input record if the delimiter is comma or white space.

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Description of Input Data Types and Content

Four types of input data can be processed by the program:

      STATES, ELEMENTS, EQ_ELEMENTS, TL_ELEMENTS

If input type is STATES, you can create an SPK of output types: 5, 8, 9, 12, 13, 15 and 17.

If input type is ELEMENTS, you can create an SPK of output types: 5, 8, 9, 12, 13, 15 and 17.

If input type is EQ_ELEMENTS, you can create only an SPK of output type 17.

If input type is TL_ELEMENTS, you can create only an SPK of output type 10.

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Input Type STATES

An input file of the STATES type must contain records consisting of EPOCH and a full set of state vector parameters X, Y, Z, VX, VY, Vz.

If you use the STATES input type to produce an SPK of Type 17, you must also include three equinoctial parameters:

      DPER/DT, DMPN/DT, DNOD/DT

in addition to the state vector.

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Input Type ELEMENTS

An input file of the ELEMENTS type must contain records consisting of EPOCH, E, INC, PER, NOD and one of A, RPI, T, P, as well as one of MEAN, EXAN, TRAN, EPOCHP, TAU.

If you use the ELEMENTS input type to produce an SPK of Type 17, you must also include three equinoctial parameters:

      DPER/DT, DMPN/DT, DNOD/DT

in addition to the state vector.

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Input Type EQ_ELEMENTS

An input file of the EQ_ELEMENTS type must contain EPOCH and nine equinoctial elements EQ_A, EQ_H, EQ_K, EQ_ML, EQ_P, EQ_Q, DPER/DT, DMPN/DT, DNOD/DT.

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Input Type TL_ELEMENTS

An input file of the TL_ELEMENTS type has a pre-defined format and is processed by the program in a special way. Therefore, the program does not need specification of the record data order and ignores all setup file keywords describing input data format.

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Relation Between Number of Input Records and Output Types

An SPK of Type 5 requires one or more input records of time ordered STATES or ELEMENTS. If the input file contains only one record, the program can formally create an SPK of Type 5 but this file will not be useful for real applications.

An SPK of Types 8, 9 requires input records of time ordered STATES or ELEMENTS. The degree of Lagrange polynomial specified by the keyword POLYNOM_DEGREE must be less than the number of the data records.

An SPK of Type 10 requires one or more input records of time ordered TL_ELEMENTS for the spacecraft with the NORAD ID specified in the OBJECT_ID setup file keyword.

An SPK of Types 12, 13 requires input records of time ordered STATES or ELEMENTS. The degree of Hermite polynomial specified by the keyword POLYNOM_DEGREE must be an odd number and less than the number of the data records times 2.

An SPK of Type 15 requires only one input record of STATES or ELEMENTS. If the input file contains more than one record, only the first is used by the program.

An SPK of Type 17 requires only one input record of EQ_ELEMENTS or one input record of STATES or ELEMENTS with DPER/DT, DMNP/DT, DNOD/DT added. If the input file contains more than one record, only the first is used by the program.

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Examples of Input Data and Setup Files

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Data Order and Data Delimiters

To use an input data file you must describe the order of data items in its data records and the delimiter used to separate these data items. You do this using appropriate keyword=value assignments in the setup file:

      DATA_ORDER     = '<param1> <param2> ... <paramN>'
      DATA_DELIMITER = '<selection>'

In some situations it is necessary to use the keyword EPOCH_STR_LENGTH to define input epoch string length, or the keyword LINES_PER_RECORD to define the number of lines used for each input record. One of these assignments may be needed to allow MKSPK to determine which characters are part of the epoch parameter as opposed to being one of the state or elements parameters.

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Example 1

The input type is STATES. We first consider the case when the delimiter separating data items is one of those also allowed as a delimiter in SPICE time strings.

Case 1. ------

It this example the data delimiter is the comma.

You have a time ordered set of states with each record consisting of one line.

      epoch1, x1, y1, z1, vx1, vy1, vz1 [,]    (record 1)
      epoch2, x2, y2, z2, vx2, vy2, vz2 [,]    (record 2)
      epoch3, x3, y3, z3, vx3, vy3, vz3 [,]    (record 3)
      epoch4, x4, y4, z4, vx4, vy4, vz4 [,]    (record 4)
      .....................................    ..........
      .....................................    ..........

Note that the data delimiter at the end of each line ( record ) is optional (as indicated by the square brackets) and may be omitted.

Let the format of each epoch string be:

      1998 DEC 12 10:23:20

You can define this input data using the following specifications in the setup file:

      INPUT_DATA_TYPE       = 'STATES'
      DATA_ORDER            = 'epoch x y z vx vy vz'
      DATA_DELIMITER        = ','
      EPOCH_STR_LENGTH      = 20

Alternatively we can use this set of specifications:

      INPUT_DATA_TYPE       = 'STATES'
      DATA_ORDER            = 'epoch x y z vx vy vz '
      DATA_DELIMITER        = ','
      LINES_PER_RECORD      = 1

This alternative method is possible because MKSPK is told that there are seven data items per line, of which the last six are the state. Therefore all other character strings are part of the epoch.

Case 2. ------

The epoch can occur in any position on the input line. For example, the input line could contain:

      x, y, z, epoch, vx, vy, vz [,]

Relative to case 1 you need to change only the order of parameters in DATA_ORDER:

      INPUT_DATA_TYPE       = 'STATES'
      DATA_ORDER            = 'x y z epoch vx vy vz'
      DATA_DELIMITER        = ','
      EPOCH_STR_LENGTH      = 20

      INPUT_DATA_TYPE       = 'STATES'
      DATA_ORDER            = 'x y z epoch vx vy vz'
      DATA_DELIMITER        = ','
      LINES_PER_RECORD      = 1

Case 3. ------

The input data use a blank (white space) as the delimiter. For example, the input line could contain:

      x y z epoch vx vy vz

You need to change only the value of DATA_DELIMITER:

      INPUT_DATA_TYPE       = 'STATES'
      DATA_ORDER            = 'x y z epoch vx vy vz'
      DATA_DELIMITER        = ' '
      EPOCH_STR_LENGTH      = 20

      INPUT_DATA_TYPE       = 'STATES'
      DATA_ORDER            = 'x y z epoch vx vy vz'
      DATA_DELIMITER        = ' '
      LINES_PER_RECORD      = 1

If the delimiter used to separate input data items is one that is not allowed as a delimiter in SPICE time strings (white space or comma), then the specifications needed in the setup file are fewer -- neither EPOCH_STR_LENGTH nor LINE_PER_RECORD is needed.

Case 4. ------

The input data use one of 'TAB', 'EOL' or ';' as delimiter. For example, if an input line contains:

      x; y; z; epoch; vx; vy; vz [;]

You should change the value of DATA_DELIMITER and omit the keyword EPOCH_STR_LENGTH or LINES_PER_RECORD:

      INPUT_DATA_TYPE       = 'STATES'
      DATA_ORDER            = 'x y z  epoch vx vy vz'
      DATA_DELIMITER        = ';'

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Example 2

This is a more general example of input data.

The input type is STATES and the delimiter is ',' which is also allowed in SPICE time strings.

You have a time ordered set of states with epochs, and each input record consists of a few lines. There are some unused parameters ('not_used') between input data values and there are blank lines between significant lines. Each input record consists of 2 significant lines with none to several intervening blank lines:

      epoch1, not_used, not_used  [,]
      blank line
      x1, y1, z1, vx1, vy1, vz1   [,]        (record 1)
      epoch2, not_used, not_used  [,]
      x2, y2, z2, vx2, vy2, vz2   [,]        (record 2)
      epoch3,  not_used, not_used [,]
      x3, y3, z3, vx3, vy3, vz3   [,]        (record 3)
      epoch4,  not_used, not_used [,]
      blank line
      blank line
      x4, y4, z4, vx4, vy4, vz4   [,]        (record 4)
      ..............................       ..........
      ..............................       ..........

The delimiter at the end of each line (record) is optional (as indicated by the square brackets) and may be omitted.

Let the format of each epoch string look like this:

      1998 DEC 12 10:23:20.617

You can define this input data using the following specification in the setup file:

      INPUT_DATA_TYPE       = 'STATES'
      DATA_ORDER            = 'epoch skip skip x y z vx vy vz'
      DATA_DELIMITER        = ','
      EPOCH_STR_LENGTH      = 24

      INPUT_DATA_TYPE       = 'STATES'
      DATA_ORDER            = 'epoch skip skip x y z vx vy vz'
      DATA_DELIMITER        = ','
      LINES_PER_RECORD      = 2

Note that the LINES_PER_RECORD assignment specifies the number of ``significant'' data lines per record -- it does not need to account for any number of intervening blank lines.

All modifications like the cases of Example 1 are possible.

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Example 3

Case 1: -------

The input type is ELEMENTS. We consider the case when the data delimiter is one of those also allowed in SPICE time strings -- white space (' ') or comma (',').

For example assume the delimiter is the comma character.

You have a time ordered set of conic elements with epochs and each input record consists of a few lines. There are some unused parameters ('not_used') between input data values and occasionally some blank lines between significant lines. Each input record consists of 2 significant lines:

      epoch1, not_used, not_used     [,]
      blank line
      e1,a1,inc1, per1, nod1, mean1  [,]        (record 1)
      epoch2, not_used, not_used     [,]
      e2,a2,inc2, per2, nod2, mean2  [,]        (record 2)
      epoch3,  not_used, not_used    [,]
      e3,a3,inc3, per3, nod3, mean   [,]        (record 3)
      epoch4,  not_used, not_used    [,]
      blank line
      blank line
      e4,a4,inc4, per4, nod4, mean4  [,]        (record 4)
      ..............................            ..........
      ..............................            ..........

The delimiter at the end of each line (record) is optional (as indicated by the square brackets) and may be omitted.

Let the format of each epoch string look like this:

      1998 DEC 12 10:23:20.3

You can define this input data using the following specification in the setup file:

      INPUT_DATA_TYPE       = 'ELEMENTS'
      DATA_ORDER            = 'epoch skip skip e a inc per nod mean'
      DATA_DELIMITER        = ','
      EPOCH_STR_LENGTH      = 22

      INPUT_DATA_TYPE       = 'ELEMENTS'
      DATA_ORDER            = 'epoch skip skip e a inc per nod mean'
      DATA_DELIMITER        = ','
      LINES_PER_RECORD      = 2

You could use, by the same rules, other elements included in the list of parameters for input type ELEMENTS, except the case when the existing epoch of periapsis is also included in the input data.

Case 2: -------

In this example you need epoch of periapsis as an additional input data item and the data delimiter is one of those also allowed in SPICE time strings -- white space (' ') or comma (','):

      epoch1, not_used, not_used        [,]
      blank line
      e1,a1,inc1, per1, nod1, epochp1   [,]        (record 1)
      epoch2, not_used, not_used        [,]
      e2,a2,inc2, per2, nod2, epochp2   [,]        (record 2)
      epoch3,  not_used, not_used       [,]
      e1,a1,inc1, per1, nod1, epochp3   [,]        (record 3)
      epoch4,  not_used, not_used       [,]
      blank line
      blank line
      e1,a1,inc1, per1, nod1, epochp4   [,]        (record 4)
      ..............................               ..........
      ..............................               ..........

The value of epochp must use the same format as for the epoch string:

      1998 DEC 12 09:12:34.9

and the length of the time string (must be the same for epoch and epochp) must be defined using the keyword EPOCH_STR_LENGTH:

      INPUT_DATA_TYPE       = 'ELEMENTS'
      DATA_ORDER            = 'epoch skip skip e a per nod epochp'
      DATA_DELIMITER        = ','
      EPOCH_STR_LENGTH      = 22

All other modifications like the cases of Example 1 are possible.

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Example 4

Input type is EQ_ELEMENTS. We consider the case when the delimiter is one of those also allowed in SPICE time strings -- white space (' ') or comma (',').

For example assume the delimiter is the comma character.

Each data record consists of two lines. There are some not used parameters ('not_used') between some of the input data values of nine equinoctial elements.

      epoch1, eq(1), eq(2), eq(3), eq(4), eq(5), eq(6) [,]
      not_used, not_used, eq(7), eq(8), eq(9), no_used [,]

The delimiter at the end of each line (record) is optional (as indicated by the square brackets) and may be omitted.

Let the format of each epoch string look like this:

      1998 DEC 12 10:23

You can define this input data using the following specification in the setup file:

      INPUT_DATA_TYPE       = 'EQ_ELEMENTS'
      DATA_ORDER            = 'epoch eq_a eq_h eq_k eq_ml
         eq_p eq_q skip skip dper/dt dmnp/dt dnod/dt skip'  (*)
      DATA_DELIMITER        = ','
      EPOCH_STR_LENGTH      = 17

      INPUT_DATA_TYPE       = 'EQ_ELEMENTS'
      DATA_ORDER            = 'epoch eq_a eq_h eq_k eq_ml
         eq_p eq_q skip skip dper/dt dmnp/dt dnod/dt skip' (*)
      DATA_DELIMITER        = ','
      LINES_PER_RECORD      = 2

(*) In a real setup file the assignment for the DATA_ORDER keywords must be on a single line. It was split to be on two lines only to fit onto the page in this document.

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Using Time Wrappers

The TIME_WRAPPER keyword allows you to modify occurrences of time strings (either "epoch" or "epochp") in an input data file, either to add a time system identifier known to SPICE or some missing but fixed additional characters. The modifier alphanumeric characters are prefixed and/or suffixed around the given time string; enter the additional alphanumeric characters needed as the value for this keyword while using the

"#"

character to indicate where the given time string data are to be placed relative to the characters being added.

As an example of providing a time string identifier, suppose the input data has ET Julian Date epoch values that look like this:

      2554617.231

The SPICE's time conversion routine STR2ET will not be able to process these tags unless a modifier known to the SPICE system is added. You must indicate to STR2ET that these values are Julian Dates in ET (now called Barycentric Dynamical Time, abbreviated as TDB) using the following assignment:

      TIME_WRAPPER = '# JD TDB'

As another example suppose the time strings are given in calendar format Pacific Standard Time and look like this:

      1999 MAR 10 14:31:22.376

You must then use the TIME_WRAPPER assignment as follows:

      TIME_WRAPPER = '# PST'

to add ``PST'' to each time string so that SPICE time parsing software inside MKSPK will properly interpret these time tags.

You can also use this assignment to add missing information. Suppose your data look like this:

      MAR 10 14:31:22.376

You should use the following TIME_WRAPPER assignment:

      TIME_WRAPPER = '1999 # UTC'

This will prefix your data with '1999 ' and suffix your data with ' UTC' so the input to the time parsing software inside MKSPK will look like:

      1999 MAR 03 10:14:22.376 UTC

A special value must be assigned to the TIME_WRAPPER keyword when input times are given as DP numbers representing ET seconds past J2000. Such time tags are not processed by STR2ET; instead, they are buffered directly as DP numbers. To process this kind of input times the TIME_WRAPPER keyword must be set as follows:

      TIME_WRAPPER = '# ETSECONDS'

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Complete Examples

Examples in this section illustrate which ``keywords=value'' assignments must be specified in a MKSPK setup file for particular combinations of the input data type and format and output SPK type. Although most of the examples create an SPK file containing trajectory of the Jovian satellite AMALTHEA with respect to Jupiter, which is a not very likely application for this program, the guidelines for creating setup files demonstrated by these examples apply to the situation when an SPK file for a spacecraft needs to be made.

If you cut and paste one of these examples to help construct your own setup file be sure to change all values that need to be updated for your particular situation.

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Input Data Type STATES / Output SPK Type 05

The Type 05 SPK represents a continuous ephemeris using a discrete set of unevenly spaced states and a two body propagation method.

The PCK file 'gravity.tpc' containing GM of the central body (Jupiter) is specified using the PCK_FILE keyword. Alternatively, Jupiter's GM can be specified using the CENTER_GM keyword. The GM value will be stored in the output SPK file together with the states. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies two lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'STATES'
   OUTPUT_SPK_TYPE   = 5
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH X Y Z VX VY VZ'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   PCK_FILE          = 'gravity.tpc'
   SEGMENT_ID        = 'SPK_STATES_05'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, R,V
   -------
   1979 MAR 05 00:00:00
    -178932.619 -28063.045 -17448.755 4.733702 -23.495860 -11.041956
   1979 MAR 05 00:02:00
    -178337.419 -30878.143 -18771.071 5.186043 -23.421245 -10.996084
   1979 MAR 05 00:04:00
    -177688.033 -33683.859 -20087.682 5.636786 -23.339517 -10.946873
   ...

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Input Data Type STATES / Output SPK Type 08

The Type 08 SPK represents a continuous ephemeris using a discrete set of evenly spaced states and a Lagrange interpolation method.

The POLYNOM_DEGREE keyword is used to specify the polynomial degree that will be used to interpolate over discreet states stored in the output SPK file; this parameter is required for SPK Type 8. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies two lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

To ensure the continuity of the interpolating polynomials over the time span covered by an SPK Type 08 segment the degree of the polynomial should be odd.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'STATES'
   OUTPUT_SPK_TYPE   = 8
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH X Y Z VX VY VZ'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   POLYNOM_DEGREE    = 9
   SEGMENT_ID        = 'SPK_STATES_08'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, R,V
   -------
   1979 MAR 05 00:00:00
    -178932.619 -28063.045 -17448.755 4.733702 -23.495860 -11.041956
   1979 MAR 05 00:02:00
    -178337.419 -30878.143 -18771.071 5.186043 -23.421245 -10.996084
   1979 MAR 05 00:04:00
    -177688.033 -33683.859 -20087.682 5.636786 -23.339517 -10.946873
   ...

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Input Data Type STATES / Output SPK Type 09

The Type 09 SPK represents a continuous ephemeris using a discrete set of unevenly spaced states and a Lagrange interpolation method.

The POLYNOM_DEGREE keyword is used to specify the polynomial degree that will be used to interpolate over discreet states stored in the output SPK file; this parameter is required for SPK Type 9. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies two lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

To ensure the continuity of the interpolating polynomials over the time span covered by an SPK Type 09 segment the degree of the polynomial should be odd.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'STATES'
   OUTPUT_SPK_TYPE   = 9
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH X Y Z VX VY VZ'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   POLYNOM_DEGREE    = 9
   SEGMENT_ID        = 'SPK_STATES_09'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, R,V
   -------
   1979 MAR 05 00:00:00
    -178932.619 -28063.045 -17448.755 4.733702 -23.495860 -11.041956
   1979 MAR 05 00:02:00
    -178337.419 -30878.143 -18771.071 5.186043 -23.421245 -10.996084
   1979 MAR 05 00:04:00
    -177688.033 -33683.859 -20087.682 5.636786 -23.339517 -10.946873
   ...

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Input Data Type STATES / Output SPK Type 12

The Type 12 SPK represents a continuous ephemeris using a discrete set of evenly spaced states and a sliding window Hermite interpolation method.

The POLYNOM_DEGREE keyword is used to specify the polynomial degree that will be used to interpolate over discreet states stored in the output SPK file; this parameter is required for SPK Type 12 and its value must be an odd number. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies two lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

To ensure the continuity of the interpolating polynomials over the time span covered by an SPK Type 12 segment the degree of the polynomial should be equivalent to 3 mod 4 (3, 7, 11, etc.)

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'STATES'
   OUTPUT_SPK_TYPE   = 12
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'B.V.Semenov, NAIF/JPL'
   DATA_ORDER        = 'EPOCH X Y Z VX VY VZ'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   POLYNOM_DEGREE    = 7
   SEGMENT_ID        = 'SPK_STATES_12'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, R,V
   -------
   1979 MAR 05 00:00:00
    -178932.619 -28063.045 -17448.755 4.733702 -23.495860 -11.041956
   1979 MAR 05 00:02:00
    -178337.419 -30878.143 -18771.071 5.186043 -23.421245 -10.996084
   1979 MAR 05 00:04:00
    -177688.033 -33683.859 -20087.682 5.636786 -23.339517 -10.946873
   ...

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Input Data Type STATES / Output SPK Type 13

The Type 13 SPK represents a continuous ephemeris using a discrete set of unevenly spaced states and a sliding window Hermite interpolation method.

The POLYNOM_DEGREE keyword is used to specify the polynomial degree that will be used to interpolate over discreet states stored in the output SPK file; this parameter is required for SPK Type 13 and its value must be an odd number. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies two lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

To ensure the continuity of the interpolating polynomials over the time span covered by an SPK Type 13 segment the degree of the polynomial should be equivalent to 3 mod 4 (3, 7, 11, etc.)

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'STATES'
   OUTPUT_SPK_TYPE   = 13
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'B.V.Semenov, NAIF/JPL'
   DATA_ORDER        = 'EPOCH X Y Z VX VY VZ'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   POLYNOM_DEGREE    = 7
   SEGMENT_ID        = 'SPK_STATES_13'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, R,V
   -------
   1979 MAR 05 00:00:00
    -178932.619 -28063.045 -17448.755 4.733702 -23.495860 -11.041956
   1979 MAR 05 00:02:00
    -178337.419 -30878.143 -18771.071 5.186043 -23.421245 -10.996084
   1979 MAR 05 00:04:00
    -177688.033 -33683.859 -20087.682 5.636786 -23.339517 -10.946873
   ...

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Input Data Type STATES / Output SPK Type 15

The Type 15 SPK represents a continuous ephemeris using a compact analytic model. The object is modeled as orbiting a central body under the influence of a central mass plus first order secular effects of the J2 term in harmonic expansion of the central body gravitational potential.

The PCK file 'gravity.tpc' containing GM and J2 of the central body (Jupiter) is specified using the PCK_FILE keyword. Alternatively, Jupiter's GM and J2 can be specified using the CENTER_GM and CENTER_J2 keywords. The CENTER_POLE_RA and CENTER_POLE_DEC keywords contain Jupiter's pole RA and DEC with respect to the reference frame specified in the REF_FRAME_NAME keyword -- in this case B1950. If these keywords wouldn't be present in the setup file the program would compute these values from data present in the PCK file 'pck00005.tpc' provided using the keyword PCK_FILE. The START_TIME and STOP_TIME keywords specifying the file coverage interval, and the PRECESSION_TYPE keyword specifying the type of precession due to J2 are required for the output SPK Type 15. Also The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies two lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'STATES'
   OUTPUT_SPK_TYPE   = 15
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH X Y Z VX VY VZ'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   START_TIME        = '1979 MAR 05'
   STOP_TIME         = '1979 MAR 06'
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   PCK_FILE          = ('pck00005.tpc' 'gravity.tpc' )
   PRECESSION_TYPE   = 'NO PRECESSION'
   CENTER_POLE_RA    = 268.001
   CENTER_POLE_DEC   = 64.504
   SEGMENT_ID        = 'SPK_STATES_15'
   \begintext

Though the input file in this example contains multiple records, only the first of them will used to create the output SPK file.

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, R,V
   -------
   1979 MAR 05 00:00:00
    -178932.619 -28063.045 -17448.755 4.733702 -23.495860 -11.041956
   1979 MAR 05 00:02:00
    -178337.419 -30878.143 -18771.071 5.186043 -23.421245 -10.996084
   1979 MAR 05 00:04:00
    -177688.033 -33683.859 -20087.682 5.636786 -23.339517 -10.946873
   ...

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Input Data Type STATES / Output SPK Type 17

The SPK data Type 17 represents a continuous ephemeris using a compact analytic model. The object is following an elliptic orbit with precessing line of nodes and argument of periapse relative to the equatorial frame of some central body. The orbit is modeled via equinoctial elements.

The PCK file 'gravity.tpc' containing GM of the central body (Jupiter) is specified using the PCK_FILE keyword. Alternatively, Jupiter's GM can be specified using the CENTER_GM keyword. The GM value is required to convert states from the input file to a set of equinoctial elements stored in the output SPK file. The CENTER_POLE_RA and CENTER_POLE_DEC keywords contain Jupiter's pole RA and DEC with respect to the reference frame specified in the REF_FRAME_NAME keyword -- in this case B1950. If these keywords wouldn't be present in the setup file the program would compute these values from data present in the PCK file 'pck00005.tpc' provided using the PCK_FILE keyword. The START_TIME and STOP_TIME keywords specifying file coverage interval are required for the output SPK Type 17. The IGNORE_FIRST_LINE keyword is used to the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies three lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file (In this example the value of DATA_ORDER is line-wrapped due to document formatting restrictions; it must be contained on a single line in an actual MKSPK setup file):

   \begindata
   INPUT_DATA_TYPE   = 'STATES'
   OUTPUT_SPK_TYPE   = 17
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH X Y Z VX VY VZ DPER/DT
   DMPN/DT DNOD/DT'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   START_TIME        = '1979 MAR 05'
   STOP_TIME         = '1979 MAR 06'
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 3
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   PCK_FILE          = ('pck00005.tpc' 'gravity.tpc')
   CENTER_POLE_RA    = 268.001
   CENTER_POLE_DEC   = 64.504
   SEGMENT_ID        = 'SPK_STATES_17'
   \begintext

Since only one state is needed to create an output SPK file of type 17, the input file in this example contains a just one record.

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, R,V, EQ_EL(7), EQ_EL(8), EQ_EL(9)
   ------------------------------------
   1979 MAR 05 00:00:00
    -178932.619 -28063.045 -17448.755 4.733702 -23.495860 -11.041956
    2.912548790268837E-05 8.363793086428307E-03 -2.898889191844143E-05

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Input Data Type ELEMENTS / Output SPK Type 05

The PCK file 'gravity.tpc' containing GM of the central body (Jupiter) is specified using the PCK_FILE keyword. Alternatively, Jupiter's GM can be specified using the CENTER_GM keyword. The GM is needed to convert elements to states and it is also contained in the output SPK file. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies two lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'ELEMENTS'
   OUTPUT_SPK_TYPE   = 5
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH RP E INC NOD PER MEAN SKIP'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   PCK_FILE          = 'gravity.tpc'
   SEGMENT_ID        = 'SPK_ELEMENTS_05'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, RP, ECC, INC, LNODE, ARGP, M0, T0
   -------------------------------------
   1979 MAR 05 00:00:00
    181803.245 0.001067 25.415 357.216 114.445 78.346 -657287949.8
   1979 MAR 05 00:02:00
    181814.040 0.001008 25.415 357.216 115.117 78.678 -657287829.8
   1979 MAR 05 00:04:00
    181824.846 0.000949 25.415 357.216 115.809 78.990 -657287709.8
   ...

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Input Data Type ELEMENTS / Output SPK Type 08

The PCK file 'gravity.tpc' containing GM of the central body (Jupiter) is specified using the PCK_FILE keyword. Alternatively, Jupiter's GM can be specified using the CENTER_GM keyword. The GM is needed to convert elements to states. The POLYNOM_DEGREE keyword is used to specify the polynomial degree that will be used to interpolate over discreet states stored in the output SPK file; this parameter is required for SPK Type 8. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies three lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'ELEMENTS'
   OUTPUT_SPK_TYPE   = 8
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH RP E INC NOD PER MEAN SKIP'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   POLYNOM_DEGREE    = 8
   PCK_FILE          = 'gravity.tpc'
   SEGMENT_ID        = 'SPK_ELEMENTS_08'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, RP, ECC, INC, LNODE, ARGP, M0, T0
   -------------------------------------
   1979 MAR 05 00:00:00
    181803.245 0.001067 25.415 357.216 114.445 78.346 -657287949.8
   1979 MAR 05 00:02:00
    181814.040 0.001008 25.415 357.216 115.117 78.678 -657287829.8
   1979 MAR 05 00:04:00
    181824.846 0.000949 25.415 357.216 115.809 78.990 -657287709.8
   ...

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Input Data Type ELEMENTS / Output SPK Type 09

The PCK file 'gravity.tpc' containing GM of the central body (Jupiter) is specified using the PCK_FILE keyword. Alternatively, Jupiter's GM can be specified using the CENTER_GM keyword. The GM is needed to convert elements to states. The POLYNOM_DEGREE keyword is used to specify the polynomial degree that will be used to interpolate over discreet states stored in the output SPK file; this parameter is required for SPK Type 9. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies three lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'ELEMENTS'
   OUTPUT_SPK_TYPE   = 9
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH RP E INC NOD PER MEAN SKIP'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   POLYNOM_DEGREE    = 8
   PCK_FILE          = 'gravity.tpc'
   SEGMENT_ID        = 'SPK_ELEMENTS_09'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, RP, ECC, INC, LNODE, ARGP, M0, T0
   -------------------------------------
   1979 MAR 05 00:00:00
    181803.245 0.001067 25.415 357.216 114.445 78.346 -657287949.8
   1979 MAR 05 00:02:00
    181814.040 0.001008 25.415 357.216 115.117 78.678 -657287829.8
   1979 MAR 05 00:04:00
    181824.846 0.000949 25.415 357.216 115.809 78.990 -657287709.8
   ...

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Input Data Type ELEMENTS / Output SPK Type 12

The PCK file 'gravity.tpc' containing GM of the central body (Jupiter) is specified using the PCK_FILE keyword. Alternatively, Jupiter's GM can be specified using the CENTER_GM keyword. The GM is needed to convert elements to states. The POLYNOM_DEGREE keyword is used to specify the polynomial degree that will be used to interpolate over discreet states stored in the output SPK file; this parameter is required for SPK Type 12 and its value must be an odd number. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies three lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'ELEMENTS'
   OUTPUT_SPK_TYPE   = 12
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'B.V.Semenov, NAIF/JPL'
   DATA_ORDER        = 'EPOCH RP E INC NOD PER MEAN SKIP'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   POLYNOM_DEGREE    = 7
   PCK_FILE          = 'gravity.tpc'
   SEGMENT_ID        = 'SPK_ELEMENTS_12'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, RP, ECC, INC, LNODE, ARGP, M0, T0
   -------------------------------------
   1979 MAR 05 00:00:00
    181803.245 0.001067 25.415 357.216 114.445 78.346 -657287949.8
   1979 MAR 05 00:02:00
    181814.040 0.001008 25.415 357.216 115.117 78.678 -657287829.8
   1979 MAR 05 00:04:00
    181824.846 0.000949 25.415 357.216 115.809 78.990 -657287709.8
   ...

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Input Data Type ELEMENTS / Output SPK Type 13

The PCK file 'gravity.tpc' containing GM of the central body (Jupiter) is specified using the PCK_FILE keyword. Alternatively, Jupiter's GM can be specified using the CENTER_GM keyword. The GM is needed to convert elements to states. The POLYNOM_DEGREE keyword is used to specify the polynomial degree that will be used to interpolate over discreet states stored in the output SPK file; this parameter is required for SPK Type 13 and its value must be an odd number. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies three lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'ELEMENTS'
   OUTPUT_SPK_TYPE   = 13
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH RP E INC NOD PER MEAN SKIP'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   POLYNOM_DEGREE    = 7
   PCK_FILE          = 'gravity.tpc'
   SEGMENT_ID        = 'SPK_ELEMENTS_13'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, RP, ECC, INC, LNODE, ARGP, M0, T0
   -------------------------------------
   1979 MAR 05 00:00:00
    181803.245 0.001067 25.415 357.216 114.445 78.346 -657287949.8
   1979 MAR 05 00:02:00
    181814.040 0.001008 25.415 357.216 115.117 78.678 -657287829.8
   1979 MAR 05 00:04:00
    181824.846 0.000949 25.415 357.216 115.809 78.990 -657287709.8
   ...

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Input Data Type ELEMENTS / Output SPK Type 15

The PCK file 'gravity.tpc' containing GM and J2 of the central body (Jupiter) is specified using the PCK_FILE keyword. Alternatively, Jupiter's GM and J2 can be specified using the CENTER_GM and CENTER_J2 keywords. The CENTER_POLE_RA and CENTER_POLE_DEC keywords contain Jupiter's pole RA and DEC with respect to the reference frame specified in the REF_FRAME_NAME keyword -- in this case B1950. If these keywords wouldn't be present in the setup file, the program would compute these value from data present in the PCK file 'pck00005.tpc' provided using the keyword PCK_FILE. The START_TIME and STOP_TIME keywords specifying the file coverage interval and the PRECESSION_TYPE keyword specifying the type of precession due to J2 are required for the output SPK Type 15. The IGNORE_FIRST_LINE keyword is used to skip the header (three lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies two lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'ELEMENTS'
   OUTPUT_SPK_TYPE   = 15
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH RP E INC NOD PER MEAN SKIP'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   START_TIME        = '1979 MAR 05'
   STOP_TIME         = '1979 MAR 06'
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   PCK_FILE          = ('pck00005.tpc' 'gravity.tpc' )
   PRECESSION_TYPE   = 'NO PRECESSION'
   CENTER_POLE_RA    = 268.001
   CENTER_POLE_DEC   = 64.504
   SEGMENT_ID        = 'SPK_ELEMENTS_15'
   \begintext

Though the input file in this example contains multiple records, only the first of them will used to create the output SPK file.

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, RP, ECC, INC, LNODE, ARGP, M0, T0
   -------------------------------------
   1979 MAR 05 00:00:00
    181803.245 0.001067 25.415 357.216 114.445 78.346 -657287949.8
   1979 MAR 05 00:02:00
    181814.040 0.001008 25.415 357.216 115.117 78.678 -657287829.8
   1979 MAR 05 00:04:00
    181824.846 0.000949 25.415 357.216 115.809 78.990 -657287709.8
   ...

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Input Data Type ELEMENTS / Output SPK Type 17

The PCK file 'gravity.tpc' containing GM of the central body (Jupiter) is specified using the PCK_FILE keyword. Alternatively, Jupiter's GM can be specified using the CENTER_GM keyword. The GM value is required to convert elements from the input file to a set of equinoctial elements stored in the output SPK file. The CENTER_POLE_RA and CENTER_POLE_DEC keywords contain Jupiter's pole RA and DEC with respect to the reference frame specified in the REF_FRAME_NAME keyword -- in this case B1950. If these keywords wouldn't be present in the setup file, the program would compute these values from data present in the PCK file 'pck00005.tpc' provided using the keyword PCK_FILE. The START_TIME and STOP_TIME keywords specifying the file coverage interval are required for the output SPK Type 17. The IGNORE_FIRST_LINE keyword is used to the header of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies three lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file (In this example the value for DATA_ORDER is wrapped due to document formatting; it must be on a single line in the actual setup file):

   \begindata
   INPUT_DATA_TYPE   = 'ELEMENTS'
   OUTPUT_SPK_TYPE   = 17
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH RP E INC NOD PER MEAN SKIP
   DPER/DT DMPN/DT DNOD/DT'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   START_TIME        = '1979 MAR 05'
   STOP_TIME         = '1979 MAR 06'
   DATA_DELIMITER    = ' '
   LINES_PER_RECORD  = 3
   IGNORE_FIRST_LINE = 3
   LEAPSECONDS_FILE  = 'naif0007.tls'
   PCK_FILE          = ('pck00005.tpc' 'gravity.tpc' )
   CENTER_POLE_RA    = 268.001
   CENTER_POLE_DEC   = 64.504
   SEGMENT_ID        = 'SPK_ELEMENTS_17'
   \begintext

Input data file:

   Test: 505 relative to 599 in frame B1950. GM= 126686536.75178
   JD, RP, ECC, INC, LNODE, ARGP, M0, T0, EQ_EL(7), EQ_EL(8), EQ_EL(9)
   ------------------------------------------------------------------
   1979 MAR 05 00:00:00
    181803.245 0.001067 25.415 357.216 114.445 78.346 -657287949.8
    2.912548790268837E-05 8.363793086428307E-03 -2.898889191844143E-05

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Input Data Type EQ_ELEMENTS / Output SPK Type 17

The CENTER_POLE_RA and CENTER_POLE_DEC keywords contain Jupiter's pole RA and DEC with respect to the reference frame specified in the REF_FRAME_NAME keyword -- in this case B1950. If these keywords wouldn't be present in the setup file, the program would compute these values from data present in the PCK file 'pck00005.tpc' that will have to be provided using the keyword PCK_FILE. The START_TIME and STOP_TIME keywords specifying the file coverage interval are required for the output SPK Type 17. The IGNORE_FIRST_LINE keyword is used to skip the header (six lines) of the input file and the LINES_PER_RECORD keyword is used to specify that each record of the input file occupies ten lines, which the program must know because the input data delimiter ' ' is one that can be used in a SPICE time string.

Setup file (In this example the value of DATA_ORDER is wrapped due to document formatting; it must be on a single line in actual setup file):

   \begindata
   INPUT_DATA_TYPE   = 'EQ_ELEMENTS'
   OUTPUT_SPK_TYPE   = 17
   OBJECT_ID         = 505
   OBJECT_NAME       = 'AMALTHEA'
   CENTER_ID         = 599
   CENTER_NAME       = 'JUPITER'
   REF_FRAME_NAME    = 'B1950'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'EPOCH EQ_A EQ_H EQ_K EQ_ML EQ_P
   EQ_Q DPER/DT DMPN/DT DNOD/DT'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   START_TIME        = '1979 MAR 05'
   STOP_TIME         = '1979 MAR 06'
   DATA_DELIMITER    = ','
   IGNORE_FIRST_LINE = 6
   LINES_PER_RECORD  = 10
   LEAPSECONDS_FILE  = 'naif0007.tls'
   TIME_WRAPPER      = '# JD'
   CENTER_POLE_RA    = 268.001
   CENTER_POLE_DEC   = 64.504
   SEGMENT_ID        = 'SPK_EQ_ELEMENTS_17'
   \begintext

Input data file:

     LABEL = 'Astrometric and Voyager data solution - JUP101',
     RCKEQX        =   2.433282500000000E+06,
     RCKNAM(01)    = 'AMALTH',
     RCKNUM(01)    = 505,
     RCKCTR(01)    = 'JUPITE',
     RCKTYP(01)    = 'EQUIN ',
       2443937.5,
       1.813655610000000E+05,
       1.713267736805066E-03,
       2.975197760058551E-03,
       1.920818611670669E+02,
      -2.939839894519083E-03,
      -7.170730998150093E-04,
       2.912548790268837E-05,
       8.363793086428307E-03,
      -2.898889191844143E-05,

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Input Data Type TL_ELEMENTS / Output SPK Type 10

The OBJECT_ID keyword contains NORAD spacecraft ID for the Mir Space Station; this ID is used to locate data in the input two-line elements file. The CENTER_ID and REF_FRAME_NAME contain required values of 399 and 'J2000' correspondingly. The PCK_FILE keyword contains the name of an Earth geophysical constants PCK file; a copy of such file is usually provided with the SPICE toolkit under the ``/data'' directory. Note that no keywords describing input data format are present in the setup file. These keywords are not needed for 'TL_ELEMENTS'/SPK 10 program runs because two-line elements files have fixed format and are processed by the program as a special case. Also note that the output SPK coverage start and stop times are automatically set to be 12 hours before the time of the first input two-line elements set and 12 hours after the time of the last input two-line elements set correspondingly.

Setup file:

   \begindata
   INPUT_DATA_TYPE   = 'TL_ELEMENTS'
   OUTPUT_SPK_TYPE   = 10
   OBJECT_ID         = 16609
   CENTER_ID         = 399
   REF_FRAME_NAME    = 'J2000'
   LEAPSECONDS_FILE  = 'naif0007.tls'
   INPUT_DATA_FILE   = 'mir.tle'
   OUTPUT_SPK_FILE   = 'mir.bsp'
   PCK_FILE          = 'geophysical.ker'
   SEGMENT_ID        = 'SPACE STATION MIR'
   PRODUCER_ID       = 'Boris Semenov, NAIF/JPL'
   \begintext

Input data file (the first two characters on each line of the sample two-line elements record -- '1 ' for the line '16609U 86017A 97 ...' and '2 ' for the line '16609 51.6542 51...' -- were taken out to fit the sample record into the page):

   Mir
   16609U 86017A   97175.09681976  .00000769  00000-0  15893-4 0  3939
   16609  51.6542  51.1598 0005239 178.2438 181.8517 15.59510867648105

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Skipping Input Data Record Tokens

The next example demonstrates how ``SKIP'' can be used in the definition of the input record contents specified using the DATA_ORDER keyword. In this example ``SKIP'' is used to ignore zero-length tokens present in the input data records. The IGNORE_FIRST_LINE keyword is used to skip one line of the header information.

Setup file:

   \begindata
   INPUT_DATA_FILE   = 'good_inputs/states:commas'
   OUTPUT_SPK_FILE   = 'good_outputs/states_commas.bsp'
   INPUT_DATA_TYPE   = 'STATES'
   OUTPUT_SPK_TYPE   = 5
   OBJECT_ID         = -557
   OBJECT_NAME       = 'GRANAT'
   CENTER_ID         = 399
   CENTER_NAME       = 'EARTH'
   REF_FRAME_NAME    = 'J2000'
   PRODUCER_ID       = 'B.V. Semenov'
   DATA_ORDER        = 'X Y Z VX VY VZ SKIP SKIP EPOCH SKIP'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   DATA_DELIMITER    = ','
   LINES_PER_RECORD  = 2
   IGNORE_FIRST_LINE = 1
   LEAPSECONDS_FILE  = 'naif0007.tls'
   PCK_FILE          = ('pck00005.tpc' 'gravity.tpc')
   SEGMENT_ID        = 'TEST'
   \begintext

Input data file:

   X,Y,Z,VX,VY,VZ,,,Epoch,,
   -79376.312,94802.228,152149.381,-.537457,.057167,.299857,
   ,,1990-01-01 00:00:00.000,,
   -111902.474,71404.027,136526.217,.031594,-.434385,-.559425,
   ,,1990-01-02 09:02:02.774,,
   -70048.213,14411.561,47294.006,1.324262,-.933652,-1.728348,
   ,,1990-01-03 09:23:15.101,,
   ...

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Two Epochs in the Input Data Records

The next example demonstrates use of the EPOCH_STR_LENGTH keyword in cases where two epoch strings -- epoch, and epoch of periapsis -- provided in input records have to be used to compute data for the output SPK file. The IGNORE_FIRST_LINE keyword is used to skip one line of the header information.

Setup file (in this example the value of DATA_ORDER is wrapped due to document formatting; it must be on a single line in the actual setup file):

   \begindata
   INPUT_DATA_TYPE   = 'ELEMENTS'
   OUTPUT_SPK_TYPE   = 5
   OBJECT_ID         = -557
   OBJECT_NAME       = 'GRANAT'
   CENTER_ID         = 399
   CENTER_NAME       = 'EARTH'
   REF_FRAME_NAME    = 'J2000'
   PRODUCER_ID       = 'N.G.Khavenson, IKI RAS, Russia'
   DATA_ORDER        = 'SKIP EPOCH E RP INC NOD PER EPOCHP
   SKIP SKIP SKIP SKIP SKIP SKIP'
   INPUT_DATA_UNITS  = ('ANGLES=DEGREES' 'DISTANCES=km')
   START_TIME        = '1998 JAN 01'
   STOP_TIME         = '1999 JAN 01'
   DATA_DELIMITER    = ','
   TIME_WRAPPER      = '# TDB'
   EPOCH_STR_LENGTH  = 30
   IGNORE_FIRST_LINE = 1
   LEAPSECONDS_FILE  = 'naif0007.tls'
   PCK_FILE          = ('pck00005.tpc' 'gravity.tpc')
   SEGMENT_ID        = 'TEST'
   \begintext

Input data file:

   JDTDB, T, e, q, i, LAN, APF, ToP, n, MA, TA, a, AD, PER
   2450819.000000000, A.D. 1998-Jan-05 12:00:00.0000,
   0.9998547684834859E+00, 0.3450736825384300E+08,
   0.1249344272957001E+03, 0.1880167631634887E+03,
   0.1301649235108716E+03,A.D. 1998-JUL-05 12:00:00.0000,
   0.1802195911346396E-09, 0.9563896596356295E-02,
   0.1601180118692756E+03, 0.2376024783190921E+12,
   0.4751704492699304E+12, 0.1997563071436828E+13,

Table of Contents

MKSPK User's Guide

Abstract

Summary

Usage

Execution of MKSPK

Setup File Format and Contents

Required Assignments

Conditional Assignments

Optional Assignments

Detailed Description of Setup File Keywords

Description of Input Data Format

Description of Input Data Parameters

Description of Input Data Types and Content

Input Type STATES

Input Type ELEMENTS

Input Type EQ_ELEMENTS

Input Type TL_ELEMENTS

Relation Between Number of Input Records and Output Types

Examples of Input Data and Setup Files

Data Order and Data Delimiters

Example 1

Example 2

Example 3

Example 4

Using Time Wrappers

Complete Examples

Input Data Type STATES / Output SPK Type 05

Input Data Type STATES / Output SPK Type 08

Input Data Type STATES / Output SPK Type 09

Input Data Type STATES / Output SPK Type 12

Input Data Type STATES / Output SPK Type 13

Input Data Type STATES / Output SPK Type 15

Input Data Type STATES / Output SPK Type 17

Input Data Type ELEMENTS / Output SPK Type 05

Input Data Type ELEMENTS / Output SPK Type 08

Input Data Type ELEMENTS / Output SPK Type 09

Input Data Type ELEMENTS / Output SPK Type 12

Input Data Type ELEMENTS / Output SPK Type 13

Input Data Type ELEMENTS / Output SPK Type 15

Input Data Type ELEMENTS / Output SPK Type 17

Input Data Type EQ_ELEMENTS / Output SPK Type 17

Input Data Type TL_ELEMENTS / Output SPK Type 10

Skipping Input Data Record Tokens

Two Epochs in the Input Data Records