KPL/IK Juno WAVES Instrument Kernel =============================================================================== This Instrument Kernel (IK) file contains parameters of the JUNO WAVES Magnetic Search Coil (MSC) and electric dipole antenna. Version and Date ------------------------------------------------------------------------------- Version 0.2 -- June 15, 2017 -- Boris Semenov, NAIF Filled in Instrument Description based on [6]. Version 0.1 -- September 7, 2010 -- Boris Semenov, NAIF Changed MSC and antenna boresight directions based on review comments by Bill Kurth and Terry Averkamp. Version 0.0 -- June 12, 2009 -- Boris Semenov, NAIF Initial Release. References ------------------------------------------------------------------------------- 1. Kernel Pool Required Reading 2. GETFOV, getfoc_c, cspice_getfov headers 3. JUNO FK file, latest version 4. WAVES CDR Presentations 5. WAVES MICD 6. WAVES PDS3 catalog file, INST_WAV.CAT, Rev 2015-10-l6 Contact Information ------------------------------------------------------------------------------- Boris V. Semenov, NAIF/JPL, (818)-354-8136, Boris.Semenov@jpl.nasa.gov Implementation Notes ------------------------------------------------------------------------------- This file is used by the SPICE system as follows: programs that make use of this kernel must ``load'' the kernel, normally during program initialization. The SPICE routine FURNSH loads a kernel file into the pool as shown below. CALL FURNSH ( 'frame_kernel_name; ) -- FORTRAN furnsh_c ( "frame_kernel_name" ); -- C cspice_furnsh, frame_kernel_name -- IDL cspice_furnsh( 'frame_kernel_name' ) -- MATLAB Once the file has been loaded, the SPICE routine GETFOV (getfov_c in C, cspice_getfov in IDL and MATLAB) can be used to retrieve FOV parameters for a given instrument or structure. This file was created and may be updated with a text editor or word processor. Naming Conventions ---------------------------------------------------------- All names referencing values in this IK file start with the characters `INS' followed by the NAIF JUNO spacecraft ID number (-61) followed by a NAIF three digit ID code for one of the WAVES components. This is the full list of names and IDs for the WAVES components described by this IK file: JUNO_WAVES_MSC -61810 JUNO_WAVES_ANTENNA -61820 The remainder of the keyword name is an underscore character followed by the unique name of the data item. For example, the WAVES antenna boresight direction in the JUNO_WAVES_ANTENNA frame is specified by: INS-61820_BORESIGHT The upper bound on the length of the name of any data item is 32 characters. If the same item is included in more than one file, or if the same item appears more than once within a single file, the latest value supersedes any earlier values. Instrument Description --------------------------------------------------------- From [6]: The Waves instrument utilizes two sensors. For the detection of the electric component of waves, an electric dipole antenna is used. The antenna is mounted on the aft flight deck, centered under solar panel wing #1 which has the Magnetometer boom at its end. Each element of the dipole is 2.8 m long. The two elements are deployed shortly after launch in a plane that is tilted aft of the aft flight deck by 45 degrees and with a subtended angle between the two elements of 120 degrees. An electric preamp is housed at the root of the two dipole elements. The symmetry axis of the dipole projected into the aft flight deck plane is parallel to the Magnetometer solar panel. The antenna pattern of the dipole for low frequencies is approximately a dipole with maximum sensitivity to electric fields parallel to the Y-axis of the spacecraft, i.e. perpendicular to both the MAG boom axis and the spin axis. For the detection of the magnetic component of waves, a magnetic search coil (MSC) is used. The search coil consists of a rod of mu-metal (permalloy) material 15 cm long with 10,000 turns of copper wire on a bobbin surrounding the rod. The coil is attached to the aft flight deck with its preamplifier mounted close by. The long axis of the MSC is parallel to the spacecraft Z axis (along the high gain antenna axis), hence, the antenna pattern is approximately that of a dipole with maximum sensitivity parallel to the spin axis of the spacecraft. Since Juno's spin axis is mostly perpendicular to Jupiter's strong magnetic field, this configuration minimizes the variation of signal at the spin frequency. Mounting Alignment -------------------------------------------------------- Refer to the latest version of the Juno Frames Definition Kernel (FK) [3] for the WAVES reference frame definitions and mounting alignment information. WAVES FOVs ---------------------------------------------------------- The MCS FOV is defined as 1 degree half-angle cone centered on the boresight parallel to the MCS core axis (the primary axis of sensitivity of the coil) and pointing along the MSC frame +Z axis (which is nominally co-aligned with the s/c +Z axis). The electric dipole antenna FOV is defined as 1 degree half-angle cone centered on the boresight parallel to a line connecting the tips of the two antenna elements (the primary axis of sensitivity of the antenna) and pointing along the antenna frame -X axis (which is nominally co-aligned with the s/c +Y axis). This diagram illustrates the MSC and antenna boresights: Solar Array 3 <-. Spin Direction ~ ~ ~ ~ ~ ~ ~ ~ `. \ .-' \. \-' .-' `-. Antenna \ .-' `-. Boresight \ .-' ----- . `-. ^ Solar Array 1 .-' +Ysc ^ `. ` | -------------------. | / | \ | | | | | / | | | | |``--.. | ' | +Yant | | `--.. | | o----> <----x +Zant | | | | . +Zsc +Xsc , | | | ..--'' | \ / | | | |..--' | \ HGA / | | | | Magnetometer `-. `. .' . V -------------------' Boom / `-. ` ----- ' .-' +Xant Solar / `-. ' Array 2 / ` .o +Zmsc /`-. .-' \ MSC Boresight ~ ~ ~ ~ <-' \ +Xmsc \ +Zsc and MSC Boresight V +Ymsc are out of the page. The keywords below define the MSC and antenna FOVs. \begindata INS-61810_FOV_FRAME = 'JUNO_WAVES_MSC' INS-61810_FOV_SHAPE = 'CIRCLE' INS-61810_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-61810_FOV_CLASS_SPEC = 'ANGLES' INS-61810_FOV_REF_VECTOR = ( 1.0, 0.0, 0.0 ) INS-61810_FOV_REF_ANGLE = ( 1.0 ) INS-61810_FOV_ANGLE_UNITS = 'DEGREES' INS-61820_FOV_FRAME = 'JUNO_WAVES_ANTENNA' INS-61820_FOV_SHAPE = 'CIRCLE' INS-61820_BORESIGHT = ( -1.0, 0.0, 0.0 ) INS-61820_FOV_CLASS_SPEC = 'ANGLES' INS-61820_FOV_REF_VECTOR = ( 0.0, 1.0, 0.0 ) INS-61820_FOV_REF_ANGLE = ( 1.0 ) INS-61820_FOV_ANGLE_UNITS = 'DEGREES' \begintext End of the IK file.