KPL/FK CASSINI Dynamic Frame Definitions for TSS =========================================================================== This kernel contains dynamic frame definitions to support the ``Thermal Synthesizer System'' (TSS) tool analysis of CASSINI mission. Version and Date --------------------------------------------------------------- Version 2.0 -- March 18, 2015 -- Boris Semenov Added CASSINI_RCS frame. Version 1.0 -- March 12, 2015 -- Boris Semenov Initial release. References --------------------------------------------------------------- 1. "Kernel Pool Required Reading" 2. "Frames Required Reading" 3. TSS USER MANUAL, Volume 5, Version 14.01 Contact Information --------------------------------------------------------------- Direct questions, comments, or concerns about the contents of this kernel to: Boris Semenov, NAIF/JPL, Boris.Semenov@jpl.nasa.gov Implementation Notes --------------------------------------------------------------- This file is used by the SPICE system as follows: programs that make use of this frame kernel must "load" the kernel using SPICE's FURNSH routine, normally during program initialization. Loading the kernel associates the data items with their names in a data structure called the "kernel pool". This file was created and may be updated with a text editor or word processor. Frames Defined in This Kernel --------------------------------------------------------------- The following frames are defined in this kernel file: Frame Name Relative To Type NAIF ID ======================= =================== ======= ======= Dynamic Frames: ------------------ CASSINI_OCS_PLA_SATURN J2000 DYNAMIC -82910 CASSINI_OCS_SUN_SATURN J2000 DYNAMIC -82911 CASSINI_RCS_SATURN J2000 DYNAMIC -82913 CASSINI_RCS_SATURN_AUX J2000 DYNAMIC -82914 TSS OCS Frame for ``Planet Orientation'' Cassini-Saturn Case --------------------------------------------------------------- The TSS OCS Frame for ``Planet Orientation'' Cassini-Saturn Case is defined in section 5.3.4 of [3] as follows: In the planet-oriented mode, the OCS Z-axis points away from the center of the planet. The X-axis points in the direction of motion and the Y-axis completes the right-handed set. This frame named 'CASSINI_OCS_PLA_SATURN' with ID -82910 is defined below as a SPICE dynamic two-vector style frame. In order for the orientation of this frame to be computed by SPICE an SPK containing Cassini trajectory must be loaded into the user application. \begindata FRAME_CASSINI_OCS_PLA_SATURN = -82910 FRAME_-82910_NAME = 'CASSINI_OCS_PLA_SATURN' FRAME_-82910_CLASS = 5 FRAME_-82910_CLASS_ID = -82910 FRAME_-82910_CENTER = -82 FRAME_-82910_RELATIVE = 'J2000' FRAME_-82910_DEF_STYLE = 'PARAMETERIZED' FRAME_-82910_FAMILY = 'TWO-VECTOR' FRAME_-82910_PRI_AXIS = 'Z' FRAME_-82910_PRI_VECTOR_DEF = 'OBSERVER_TARGET_POSITION' FRAME_-82910_PRI_OBSERVER = 'SATURN' FRAME_-82910_PRI_TARGET = 'CASSINI' FRAME_-82910_PRI_ABCORR = 'NONE' FRAME_-82910_SEC_AXIS = 'X' FRAME_-82910_SEC_VECTOR_DEF = 'OBSERVER_TARGET_VELOCITY' FRAME_-82910_SEC_OBSERVER = 'SATURN' FRAME_-82910_SEC_TARGET = 'CASSINI' FRAME_-82910_SEC_ABCORR = 'NONE' FRAME_-82910_SEC_FRAME = 'J2000' \begintext TSS OCS Frame for ``Sun Orientation'' Sun-Saturn Case --------------------------------------------------------------- The TSS OCS Frame for ``Sun Orientation'' Sun-Saturn Case is defined in section 5.3.4 of [3] as follows: For the sun oriented option ... The vehicle +Z axis is parallel to the planet/sun vector and effectively points towards the sun. The +X axis lies in the equatorial plane and the +Y axis forms the right-handed set. NOTE: this definition is ambiguous as it does not constrain +Y axis to pointing towards north pole or south pole. The diagram accompanying the definition had +Y axis pointing toward the north pole. So that's what's implemented in this FK. This frame named 'CASSINI_OCS_SUN_SATURN' with ID -82911 is defined below as a SPICE dynamic two-vector style frame. In order for the orientation of this frame to be computed by SPICE an SPK containing Cassini trajectory and a generic PCK must be loaded into the user application. \begindata FRAME_CASSINI_OCS_SUN_SATURN = -82911 FRAME_-82911_NAME = 'CASSINI_OCS_SUN_SATURN' FRAME_-82911_CLASS = 5 FRAME_-82911_CLASS_ID = -82911 FRAME_-82911_CENTER = -82 FRAME_-82911_RELATIVE = 'J2000' FRAME_-82911_DEF_STYLE = 'PARAMETERIZED' FRAME_-82911_FAMILY = 'TWO-VECTOR' FRAME_-82911_PRI_AXIS = 'Z' FRAME_-82911_PRI_VECTOR_DEF = 'OBSERVER_TARGET_POSITION' FRAME_-82911_PRI_OBSERVER = 'SATURN' FRAME_-82911_PRI_TARGET = 'SUN' FRAME_-82911_PRI_ABCORR = 'NONE' FRAME_-82911_SEC_AXIS = 'Y' FRAME_-82911_SEC_VECTOR_DEF = 'CONSTANT' FRAME_-82911_SEC_SPEC = 'RECTANGULAR' FRAME_-82911_SEC_VECTOR = ( 0.0, 0.0, 1.0 ) FRAME_-82911_SEC_FRAME = 'IAU_SATURN' \begintext TSS RCS Frame --------------------------------------------------------------- The TSS RCS Frame for Saturn is defined in section 5.3.4 of [3] as follows: "... reference coordinate system (RCS) centered about the planet being orbited. This provides a frame of reference in which the locations of the sun and the orbit are tied together. The RCS X-axis points toward the vernal equinox of the planet being orbited (the intersection of the equatorial and ecliptic planes and pointing in the direction where the sun crosses the equator heading north). The Z-axis passes throughout the North Pole of the planet. The Y-axis completes the right-handed set." Based on clarification from Joe Lepore, Spacedesign Corporation, that in TSS "the obliquity of the ecliptic set to a constant 26.73 for Saturn" and the declination of the Sun relative in the RCS frame is computed from the right ascension of the Sun using this formula declination = orb_get_obliquity() * sin( right_ascension * M_PI/180.0 ); the "ecliptic plane" in the definition above means the mean Saturn orbit plane. The RCS frame named 'CASSINI_RCS_SATURN' with ID -82913 is defined below as a SPICE dynamic two-vector style frame. As its secondary defining vector it uses the Z axis of the 'CASSINI_RCS_SATURN_AUX' frame (ID -82914), which is a two vector frame based on Saturn position and velocity with respect to Sun. This +Z axis is co-aligned with Saturn orbital instantaneous angular momentum. In order for the orientation of these frames to be computed by SPICE an SPK containing Saturn ephemeris and a generic PCK must be loaded into the user application. \begindata FRAME_CASSINI_RCS_SATURN = -82913 FRAME_-82913_NAME = 'CASSINI_RCS_SATURN' FRAME_-82913_CLASS = 5 FRAME_-82913_CLASS_ID = -82913 FRAME_-82913_CENTER = -82 FRAME_-82913_RELATIVE = 'J2000' FRAME_-82913_DEF_STYLE = 'PARAMETERIZED' FRAME_-82913_FAMILY = 'TWO-VECTOR' FRAME_-82913_PRI_AXIS = 'Z' FRAME_-82913_PRI_VECTOR_DEF = 'CONSTANT' FRAME_-82913_PRI_SPEC = 'RECTANGULAR' FRAME_-82913_PRI_VECTOR = ( 0.0, 0.0, 1.0 ) FRAME_-82913_PRI_FRAME = 'IAU_SATURN' FRAME_-82913_SEC_AXIS = 'Y' FRAME_-82913_SEC_VECTOR_DEF = 'CONSTANT' FRAME_-82913_SEC_SPEC = 'RECTANGULAR' FRAME_-82913_SEC_VECTOR = ( 0.0, 0.0, -1.0 ) FRAME_-82913_SEC_FRAME = 'CASSINI_RCS_SATURN_AUX' FRAME_-82913_ROTATION_STATE = 'INERTIAL' FRAME_CASSINI_RCS_SATURN_AUX = -82914 FRAME_-82914_NAME = 'CASSINI_RCS_SATURN_AUX' FRAME_-82914_CLASS = 5 FRAME_-82914_CLASS_ID = -82914 FRAME_-82914_CENTER = -82 FRAME_-82914_RELATIVE = 'J2000' FRAME_-82914_DEF_STYLE = 'PARAMETERIZED' FRAME_-82914_FAMILY = 'TWO-VECTOR' FRAME_-82914_PRI_AXIS = 'X' FRAME_-82914_PRI_VECTOR_DEF = 'OBSERVER_TARGET_POSITION' FRAME_-82914_PRI_OBSERVER = 'SUN' FRAME_-82914_PRI_TARGET = 'SATURN' FRAME_-82914_PRI_ABCORR = 'NONE' FRAME_-82914_SEC_AXIS = 'Y' FRAME_-82914_SEC_VECTOR_DEF = 'OBSERVER_TARGET_VELOCITY' FRAME_-82914_SEC_OBSERVER = 'SUN' FRAME_-82914_SEC_TARGET = 'SATURN' FRAME_-82914_SEC_ABCORR = 'NONE' FRAME_-82914_SEC_FRAME = 'J2000' \begintext End of FK.