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 0.6 -- November 29, 2016 -- Marc Costa Sitja, ESAC/ESA Updated description and added Channel 1 and Channel 2 FOV definitions. Version 0.5 -- October 27, 2016 -- Marc Costa Sitja, ESAC/ESA Changed SWI Sensors Field-of-views names. JUICE_SWI_BASE is now called JUICE_SWI_FULL and JUICE_SWI_SCANNEr is called JUICE_SWI. Initial Release. Pending review by the SWI instrument team. Version 0.4 -- October 7, 2016 -- Marc Costa Sitja, ESAC/ESA Corrected SWI_BASE FOV_REF_VECTOR since it was rotated 90 deg as indicated in [6]. 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. 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 6. E-mail from Christian Erd "SWI Orientation" from 22 September 2016. 7. ``JUICE - JUpiter Icy Moons Explorer SWI - Submillimetre Wave Instrument. Experiment Interface Document EID-B,'' JUI-MPS-SWI-EID-001 Issue 4.4, 31 August 2016 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_FULL -28800 JUICE_SWI_CH1 -28810 JUICE_SWI_CH2 -28820 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 ------------------------------------------------------------------------------- The Submillimetre Wave Instrument (SWI) will study the Galilean satellites, the chemistry, meteorology and structure of Jupiter’s middle atmosphere and atmospheric and magnetospheric coupling processes (from []). SWI is passive heterodyne microwave spectrometer sensitive for radiation in the frequency band of 530–625 GHz for the channel one (Band#1) and 1088-1267 GHz (Band#2) for channel two. The radiation is received through a quasi-optical off-axis telescope with 30 cm aperture diameter, providing a spatial resolution of 2 mrad (FWHM) at 600 GHz and is collimated into the Receiver Unit. This telescope is equipped with a two-axis scan mechanism to allow scanning around the nadir viewing direction in a range of +/-76 degrees inside the spacecraft’s orbital plane and +/-4.3 degrees perpendicular to the plane. Two independent double sideband receivers are used to obtain simultaneous observing capability for two different frequencies bands. Each receiver is connected to its own high-resolution Chirp Transform Spectrometer (CTS), providing a total bandwidth of 1 GHz at 100 kHz resolution (10000 equidistant channels). 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). To allow a larger bandwidth coverage at lower resolution for surface emission measurements of Jupiter’s satellites, SWI is equipped with two autocorrelator spectrometers (ACS) (5 GHz bandwidth, programmable 256, 512, 758 or 1024 channels) and two continuum detectors (5 GHz bandwidth) as well. For radiometric calibration, the SWI instrument uses an internal blackbody as hot reference load and the cold sky as external cold reference load. The hot reference load is coupled into the beam internally via a calibration flip mirror. The cold sky is viewed by turning away the telescope from Jupiter respective the satellite under investigation. The local oscillators for the two receivers are tunable in frequency, so SWI is able to observe any specific transition within the frequency bands. The main characteristics of SWI are provided in the following table: ------------------------------------------------ PARAMETER VALUE --------------------------- ------------------ Frequency Bands CH1 530-625 GHz CH2 1088-1267GHz Field of Views CH1 2 mrad CH2 1 mrad DSB Sensitivity 2000 K IF Bandwidth 3.5–8.5 GHz CTS Bandwidth 1 GHz CTS Center Frequency 6 GHz CTS Spectral Coverage 530–625 GHz Delta_f/f 1.6x10-7 ACS Bandwidth CH1 4.6-8.6 GHz CH2 0.2-4.2 GHz ACS Frequency Resolution 20 MHz Frequency Stability 1x10-8 Delta_f/f Antenna aperture 30 cm Antenna edge taper 20 dB FHWM beam width at 600 GHz 2 mrad Nominal power consumption 58.2 W average 69.1 W long peak Basic instrument mass 11.37 kg Maximum Data rate 5.23 kbits/sec ------------------------------------------------ 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 Channel 1 apparent FoV layout (JUICE_SWI_CH1) in the JUICE_SWI_SCANNER reference frame and an auxiliary field-of-viee circumscribing the full range of positions due to the reflector rotations (JUICE_SWI_FULL) in the JUICE_SWI_BASE reference frame. The SWI Channel 2 apparent FoV is not shown in the diagram. 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. Xswi_base (along-track in Jupiter phase ^ across-track in Ganymede phase) x - - - - | - - - - x ------------------ | | | ^ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SWI_FULL FoV . - . ------------ | Yswi_base | / | \ | ^ | 152.11459 deg <----------------------o | | 2mrad | (aling-track in | \ | / | v (FoV) | Jupiter phase; ` - ' ------------ | across-track | | SWI_CH1 FoV | in Ganymede | | phase) | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 Channel #1 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_CH1. \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 The SWI Channel #2 field of view is defined based on the receiver main beam half power point directions (-1.5 dB), and corresponds to a half-cone of 0.5-mrad (see [7]). The following FOV definition corresponds to the NAIF Body Name: JUICE_SWI_CH2. \begindata INS-28820_FOV_FRAME = 'JUICE_SWI_SCANNER' INS-28820_FOV_SHAPE = 'CIRCLE' INS-28820_BORESIGHT = ( 0.000, 0.000, 1.000 ) INS-28820_FOV_CLASS_SPEC = 'ANGLES' INS-28820_FOV_REF_VECTOR = ( 0.000, 1.000, 0.000 ) INS-28820_FOV_REF_ANGLE = ( 0.0005 ) INS-28820_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_FULL) 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_FULL. \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 = ( 1.0, 0.0, 0.0 ) INS-28800_FOV_REF_ANGLE = ( 76.057295 ) INS-28800_FOV_CROSS_ANGLE = ( 4.357295 ) INS-28800_FOV_ANGLE_UNITS = 'DEGREES' \begintext End of IK file.