KPL/IK SWI Instrument Kernel =============================================================================== This instrument kernel (I-kernel) contains the JUICE Sub-millimeter Wave Instrument (SWI) instrument field-of-view (FOV) parameters. Version and Date ------------------------------------------------------------------------------- Version 0.3 -- June 04, 2016 -- Marc Costa Sitja, ESAC/ESA Updated all NAIF ID codes from -907* to -28* since the JUICE spacecraft NAIF ID has been updated from -907 to -28. Initial Release. Pending review by the SWI instrument team. Version 0.2 -- May 12, 2016 -- Jorge Diaz del Rio, ODC Space Added instrument description. Preliminary version. Pending review by the SWI instrument team. Version 0.1 -- February 28, 2016 -- Jorge Diaz del Rio, ODC Space Preliminary version. Pending review by the SWI instrument and JUICE Science Operations Working Group team. Version 0.0 -- July 24, 2013 -- Marc Costa Sitja, ISDEFE/ESA Initial Release. References ------------------------------------------------------------------------------- 1. ``Kernel Pool Required Reading'' 2. ``C-kernel Required Reading'' 3. JUICE Frames Definition Kernel (FK), latest version. 4. ``JUICE - Jupiter Icy Moons Explorer. Exploring the emergence of habitable worlds around gas giants. Definition Study report,'' ESA/SRE(2014)1, September 2014 (JUICE Red book v1.0) 5. ``JUICE - JUpiter Icy Moons Explorer SWI - Submillimetre Wave Instrument. Experiment Interface Document EID-B,'' JUI-MPS-SWI-EID-001 Issue 4.3, 17 July 2015 Contact Information ------------------------------------------------------------------------------- If you have any questions regarding this file contact SPICE support at ESAC: Marc Costa Sitja (+34) 91-8131-457 mcosta@sciops.esa.int, esa_spice@sciops.esa.int or NAIF at JPL: Boris Semenov (818) 354-8136 Boris.Semenov@jpl.nasa.gov Implementation Notes ------------------------------------------------------------------------------- Applications that need SPICE I-kernel data must ``load'' the I-kernel file, 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 Loading the kernel using the SPICELIB routine FURNSH causes the data items and their associated values present in the kernel to become associated with a data structure called the ``kernel pool''. 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. The application program may obtain the value(s) for any other IK data item using the SPICELIB routines GDPOOL, GIPOOL, GCPOOL (gdpool_c, gipool_c, gcpool_c in C, cspice_gdpool, cspice_gipool, cspice_gcpool in IDL and MATLAB). See [1] for details. This file was created with, and can be updated with a text editor or word processor. Naming Conventions and Conventions for Specifying Data ------------------------------------------------------------------------------- All names referencing values in this IK file start with the characters `INS' followed by the NAIF JUICE spacecraft ID number (-28) followed by a NAIF three digit ID code for one of the SWI ``sensors''. This is the full list of names and IDs for the SWI structures described by this IK file: Name NAIF ID --------------------- --------- JUICE_SWI_BASE -28800 JUICE_SWI -28810 The remainder of the keyword name is an underscore character followed by the unique name of the data item. For example, the Sub-millimeter Wave Instrument boresight direction in the JUICE_SWI frame is specified by: INS-28810_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 and Overview ------------------------------------------------------------------------------- SWI is a heterodyne spectrometer covering the frequency range from 530 GHz to 625 GHz using two receivers with vertical and horizontal polarization (see [4] and [5]). The submillimetre wave radiation is collected by a diffraction limited elliptical reflector with projected 30 cm aperture and collimated into the Receiver Unit. The reflector can be rotated by +/-76 degrees along track (Jupiter) and +/-4.3 degrees cross track. The signal is down-converted by multiplication with a tunable local oscillator (LO) signal to an intermediate frequency band (IF) from 4 to 8 GHz (C-band) using passively cooled (Radiator) subharmonically pumped mixers (SHM). The LO consists of K-band synthesizers, frequency controlled against an Ultra Stable Oscillator (USO), E-band triplers and Power Amplifiers (PA) and two cascaded G-band doublers. The final frequency doubling takes place in the SHM. After amplification using a Low Noise Amplifier (LNA) the IF-signal feeds high resolution Chirp Transform Spectrometers (CTS) broadband Autocorrelation Spectrometers (ACS) and continuum channels (CCH). The main characteristics of SWI are provided in the following table: ------------------------------------------- PARAMETER VALUE --------------------------- ------------- Frequency Band 530-625 GHz Field of View 2 mrad DSB Sensitivity 2000 K IF Bandwidth 4 GHz CTS Bandwidth 1 GHz CTS Spectral Resolution 0.1 MHz Delta_f/f 1.6x10-7 ACS Bandwidth 4 GHz ACD Spectral Resolution 16 MHz Frequency Stability 1x10-8 Delta_f/f ------------------------------------------- The main observing modes are limb and nadir sounding (Jupiter: pointing, Ganymede, Callisto and Europa: scanning), complemented by solar occultation measurements. Since SWI is a single pixel instrument with low data rate, mapping observations require the instrument to operate permanently. Mounting Alignment ------------------------------------------------------------------------------- Refer to the latest version of the JUICE Frames Definition Kernel (FK) [3] for the SWI reference frame definitions and mounting alignment information. SWI Field-of-View Layout ------------------------------------------------------------------------------- This section provides a diagram illustrating the SWI apparent FoV layout in the JUICE_SWI_BASE reference frame and an auxiliary field-of-view circumscribing the full range of positions due to the reflector rotations. Note that the SWI Field-of-View is zoomed with respect to the auxiliary field-of-view, and that the shape of the later does not match reality. Yswi_base (along-track) ^ x - - - - | - - - - x ------------------ | | | ^ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SWI_BASE FoV . - . ------------ | Xswi_base | / | \ | ^ | 152.11459 deg <----------------------o | | 2mrad | along-track | \ | / | v (FoV) | ` - ' ------------ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | v x - - - - | - - - - x ------------------ | | |<----------------->| | 8.71459 deg | The reflector can be rotated by +/-76 degrees along track and +/-4.3 degrees cross track. SWI Field of View Definition ------------------------------------------------------------------------------- The SWI field of view is defined based on the receiver main beam half power point directions (-3 dB), and corresponds to a half-cone of 1-mrad (see [5]). The following FOV definition corresponds to the NAIF Body Name: JUICE_SWI. \begindata INS-28810_FOV_FRAME = 'JUICE_SWI_SCANNER' INS-28810_FOV_SHAPE = 'CIRCLE' INS-28810_BORESIGHT = ( 0.000, 0.000, 1.000 ) INS-28810_FOV_CLASS_SPEC = 'ANGLES' INS-28810_FOV_REF_VECTOR = ( 0.000, 1.000, 0.000 ) INS-28810_FOV_REF_ANGLE = ( 0.001 ) INS-28810_FOV_ANGLE_UNITS = 'RADIANS' \begintext An auxillary FOV approximately circumscribing the full range of positions due to the SWI reflector rotation is defined for the ``instrument'' ID -28800 (JUICE_SWI_BASE) as a rectangular pyramid centered on the +Z axis of the JUICE_SWI_BASE frame with half angular extents of 76.057295 degrees (76 degree scan + 1/2 of 2mrad FOV height) in the YZ plane and 4.357295 degrees (4.3 degree scan + 1/2 of 2mrad FOV width) in XZ plane of the JUICE_SWI_BASE frame. The following FOV definition corresponds to the NAIF Body Name: JUICE_SWI_BASE. \begindata INS-28800_FOV_FRAME = 'JUICE_SWI_BASE' INS-28800_FOV_SHAPE = 'RECTANGLE' INS-28800_BORESIGHT = ( 0.0, 0.0, 1.0 ) INS-28800_FOV_CLASS_SPEC = 'ANGLES' INS-28800_FOV_REF_VECTOR = ( 0.0, 1.0, 0.0 ) INS-28800_FOV_REF_ANGLE = ( 76.057295 ) INS-28800_FOV_CROSS_ANGLE = ( 4.357295 ) INS-28800_FOV_ANGLE_UNITS = 'DEGREES' \begintext