KPL/IK RSS Instrument Kernel ============================================================================== This instrument kernel (I-kernel) contains references to the mounting alignment, internal and FOV geometry for the Cassini Radio Science Subsytem (RSS). Version and Date ---------------------------------------------------------- The TEXT_KERNEL_ID stores version information of loaded project text kernels. Each entry associated with the keyword is a string that consists of four parts: the kernel name, version, entry date, and type. For example, the ISS I-kernel might have an entry as follows: TEXT_KERNEL_ID += 'CASSINI_ISS V0.0.0 29-SEPTEMBER-1999 IK' | | | | | | | | KERNEL NAME <-------+ | | | | | V VERSION <-------+ | KERNEL TYPE | V ENTRY DATE RSS I-Kernel Version: \begindata TEXT_KERNEL_ID += 'CASSINI_RSS V0.3.0 18-APRIL-2003 IK' \begintext Version 0.3 -- April 18, 2003 -- Lee Elson -- Added a new instrument, X BAND TRUE, that contains the old X BAND instrument FOV definitions. Altered X BAND definitions so that they are the same as Ka band. This is necessary because of the way that the uplink software uses the information. See the updated frame kernel for more information. The ID for X BAND TRUE is -82186, the name is CASSINI_RSS_HGA_X_TRUE. Version 0.2 -- April 23, 2001 -- Scott Turner -- Updated kernel to utilize new FOV ANGLES specification. Version 0.1 -- November 2, 2000 -- Scott Turner -- Fixed a formatting error in the FOV size table. -- In the previous version, the SBAND pixel parameter keywords were mistakenly omitted. They have been added. Version 0.0 -- October 5, 2000 -- Scott Turner -- Initial Prototype Release for Review References ---------------------------------------------------------- 1. ``Cassini Science Instruments and Investigations'', Revised Second Printing. Stephen J. Edberg. 2. ``Kernel Pool Required Reading'' 3. JPL Cassini Project Web Page describing the instruments. 4. Cassini/NAIF SPICE Workship, November 8-9, 1999. 5. Email from Jeff Boyer regarding necessary data for footprint calculations. 6. Cassini Spacecraft Frames Definition Kernel 7. CASPER RSS I-kernel Version 2.0 Contact Information ---------------------------------------------------------- Direct questions, comments or concerns about the contents of this kernel to: Lee Elson, NAIF/JPL, (818)-354-4223, Lee.Elson@jpl.nasa.gov Implementation Notes ---------------------------------------------------------- This file is used by the SPICE system as follows: programs that make use of this instrument kernel must ``load'' the kernel, normally during program initialization. Loading the kernel associates data items with their names in a data structure called the ``kernel pool''. The SPICELIB routine FURNSH and CSPICE routine furnsh_c load SPICE kernels as shown below: FORTRAN (SPICELIB) CALL FURNSH ( 'kernel_name' ) C (CSPICE) furnsh_c ( "kernel_name" ) In order for a program or subroutine to extract data from the pool, the SPICELIB routines GDPOOL and GIPOOL are used. See [2] for details. This file was created and may be updated with a text editor or word processor. Naming Conventions ---------------------------------------------------------- All names referencing values in this I-kernel start with the characters `INS' followed by the NAIF Cassini spacecraft ID number (-82) followed by a NAIF three digit code for the RSS instruments. (KABAND = 180, KUBAND = 181, SBAND = 182 , XBAND = 183, LGA1 = 184, LGA2 = 185, XBAND_TRUE = 186 ). The remainder of the name is an underscore character followed by the unique name of the data item. For example, the KABAND boresight direction in the KABAND frame (``CASSINI_KABAND'' -- see [6] ) is specified by: INS-82180_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. RSS description ---------------------------------------------------------- From [3]: Radio science experiments use the spacecraft radio and ground antennas (such as those of NASA's Deep Space Network) as the science instrument. These experiments measure the refractions, Doppler shifts, and other modifications to radio signals that occur when the spacecraft is "occulted" by (i.e., passes behind) planets, moons, atmospheres, and physical features such as planetary rings. From these measurements, scientists can derive information about the structures and compositions of the occulting bodies, atmospheres, and rings. The Radio Science Subsystem (RSS) will use the spacecraft X-band communication link as well as the S-band downlink and the Ka-band uplink and downlink to study the compositions, pressures, and temperatures of the atmospheres and ionospheres of Saturn and Titan; the radial structure of Saturn's rings and the particle size distribution within the rings; and body and system masses within the Saturnian system. It will also be used to search for gravitational waves coming from beyond our solar system. The RSS consists of a Ka-band traveling wave tube amplifier, a translator, an exciter; an S-band transmitter; and various microwave components. For more information on these components, see below. (NOTE: Before proceeding, you may wish to review the description of the Radio Frequency Subsystem (RFS). The purpose of the Ka-band traveling wave tube amplifier (K-TWTA) subassembly is to amplify the signals going to the high-gain antenna to the power level necessary for them to be received by the Deep Space Network. The K-TWTA subassembly consists of the a traveling wave tube (TWT) and an electronic power conditioner (EPC). The nonredundant TWT is the signal amplifier. It can be commanded into a standby mode for low d.c. power consumption. The EPC converts d.c. power from the Power and Pyrotechnic Subsystem (PPS) to the voltages required to operate the TWT. It can power the TWT in the standby mode or power down the TWT in case of TWT or EPC fault detection. The EPC also supplies engineering telemetry to the RFS and provides direct-access signals. The Ka-band translator (KAT) subassembly receives the 34-GHz uplink carrier from the high-gain antenna and translates it by a factor of 14/15 for retransmission back to the DSN. The phase and phase-shift of the signal are used for the actual science observations and measurements. The KAT contains a power converter that allows it to operate from the 30-volt d.c. power bus. It also supplies engineering telemetry data to the RFS and provides for direct access. The Ka-band exciter (KEX) generates a stable 32-GHz signal and provides an RF power combiner to combine the RF signal generated by the KAT with its own signal. It is powered by the 30-volt spacecraft bus, and it supplies telemetry data to the RFS and provides direct access. The S-band transmitter (SBT) receives a 115-MHz signal from the RFS, multiplies it by 20, amplifies it to 10 watts, and supplies the resultant signal at approximately 2290 MHz to the high-gain antenna. This carrier signal is used for radio science experiments. The transmitter contains a power converter to allow operation from the 30-volt power bus, and it supplies telemetry data to the RFS and provides direct access. The microwave components consist of two band pass filters (BPFs) and waveguide components. BPFs are filters that allow only certain wavelengths of microwave energy to pass, with all other wavelengths being blocked. In this case, the BPFs permit reception and transmission of the Ka-band signals using different antenna feed polarizations and provide isolation between the transmit and receive frequencies. Waveguide is essentially tubing of precise dimensions that provides a path for microwave energy of a certain wavelength. In this subsystem it is used for all Ka-band microwave component interconnections. RSS Field of View Parameters ---------------------------------------------------------- The field of view parameters for the six instruments that constitute the RSS are: -- KA Band (KABAND) -- KU Band (KUBAND) -- S Band (SBAND) -- X Band (XBAND) -- X Band True (XBAND_TRUE) -- Low Gain Antenna 1 (LGA1) -- Low Gain Antenna 2 (LGA2) Circular FOV: ------------ ----------------------- Beam Diameter ------------ ----------------------- KABAND 0.19022199 degrees KUBAND 0.350 degrees SBAND 2.14859180 degrees XBAND 0.19022199 degrees (forced identical to KABAND) XBAND_TRUE 0.55977977 degrees LGA1 0.010 degrees LGA2 0.010 degrees ------------ ----------------------- The keywords INS[ID]_FOV_FRAME, INS[ID]_FOV_SHAPE, INS[ID]_BORESIGHT, and FOV ANGLES specification keywords defined below are used to describe the instrument field of view. Since the beams have circular fields of view, the INS[ID]_FOV_SHAPE will be 'CIRCLE'. GETFOV returns a single vector that lies along the edge of the circular cone. All six FOV boresights lie along the Z-axis. KA Band (KABAND) FOV Definition Since the KABAND's FOV is circular and its diameter is 0.19022199 degrees, looking down the X-axis in the CASSINI_KABAND frame, we have: (Note we are arbitrarily choosing a vector that terminates in the Z=1 plane.) ^ Y | ins | | /| | / | | / | | / o | |/ 0.095 | x---------------> X \ | Z ins \ | ins \ | \ | \| |-- 1.0 --| Plane X = 0 Now from here we see that the Y component of one 'boundary corner' vector is: Y Component = 1.0 * tan ( 0.095110995 degrees ) = 0.001660002 Utilizing the ANGLES FOV specification: \begindata INS-82180_FOV_FRAME = 'CASSINI_KABAND' INS-82180_FOV_SHAPE = 'CIRCLE' INS-82180_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82180_FOV_CLASS_SPEC = 'ANGLES' INS-82180_FOV_REF_VECTOR = ( 0.0000000000000000 +1.0000000000000000 0.0000000000000000 ) INS-82180_FOV_REF_ANGLE = ( 0.095110995 ) INS-82180_FOV_ANGLE_UNITS = 'DEGREES' \begintext KU Band (KUBAND) FOV Definition Since the KUBAND's FOV is circular and its diameter is 0.35 degrees, looking down the X-axis in the CASSINI_KUBAND frame, we have: (Note we are arbitrarily choosing a vector that terminates in the Z=1 plane.) ^ Y | ins | | /| | / | | / | | / o | |/ 0.175 | x---------------> X \ | Z ins \ | ins \ | \ | \| |-- 1.0 --| Plane X = 0 Now from here we see that the Y component of one 'boundary corner' vector is: Y Component = 1.0 * tan ( 0.35 degrees ) = 0.003054336 Utilizing the ANGLES FOV specification: \begindata INS-82181_FOV_FRAME = 'CASSINI_KUBAND' INS-82181_FOV_SHAPE = 'CIRCLE' INS-82181_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82181_FOV_CLASS_SPEC = 'ANGLES' INS-82181_FOV_REF_VECTOR = ( 0.0000000000000000 +1.0000000000000000 0.0000000000000000 ) INS-82181_FOV_REF_ANGLE = ( 0.175 ) INS-82181_FOV_ANGLE_UNITS = 'DEGREES' \begintext S Band (SBAND) FOV Definition Since the SBAND's FOV is circular and its diameter is 2.14859180 degrees, looking down the X-axis in the CASSINI_SBAND frame, we have: (Note we are arbitrarily choosing a vector that terminates in the Z=1 plane.) ^ Y | ins | | /| | / | | / | | / o | |/ 1.074 | x---------------> X \ | Z ins \ | ins \ | \ | \| |-- 1.0 --| Plane X = 0 Now from here we see that the Y component of one 'boundary corner' vector is: Y Component = 1.0 * tan ( 1.0742959 degrees ) = 0.018752198 Utilizing the ANGLES FOV specification: \begindata INS-82182_FOV_FRAME = 'CASSINI_SBAND' INS-82182_FOV_SHAPE = 'CIRCLE' INS-82182_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82182_FOV_CLASS_SPEC = 'ANGLES' INS-82182_FOV_REF_VECTOR = ( 0.0000000000000000 +1.0000000000000000 0.0000000000000000 ) INS-82182_FOV_REF_ANGLE = ( 1.0742959 ) INS-82182_FOV_ANGLE_UNITS = 'DEGREES' \begintext X Band (XBAND) FOV Definition The XBAND parameters are set equal to the Ka band parameters. Therefore the XBAND's FOV is circular and its diameter is 0.19022199 degrees, looking down the X-axis in the CASSINI_XBAND frame, we have: (Note we are arbitrarily choosing a vector that terminates in the Z=1 plane.) ^ Y | ins | | /| | / | | / | | / o | |/ 0.095 | x---------------> X \ | Z ins \ | ins \ | \ | \| |-- 1.0 --| Plane X = 0 Now from here we see that the Y component of one 'boundary corner' vector is: Y Component = 1.0 * tan ( 0.095110995 degrees ) = 0.001660002 Utilizing the ANGLES FOV specification: \begindata INS-82183_FOV_FRAME = 'CASSINI_XBAND' INS-82183_FOV_SHAPE = 'CIRCLE' INS-82183_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82183_FOV_CLASS_SPEC = 'ANGLES' INS-82183_FOV_REF_VECTOR = ( 0.0000000000000000 +1.0000000000000000 0.0000000000000000 ) INS-82183_FOV_REF_ANGLE = ( 0.095110995 ) INS-82183_FOV_ANGLE_UNITS = 'DEGREES' \begintext Low Gain Antenna 1 (LGA1) FOV Definition Since the LGA1's FOV is circular and its diameter is 0.010 degrees, looking down the X-axis in the CASSINI_LGA1 frame, we have: (Note we are arbitrarily choosing a vector that terminates in the Z=1 plane.) ^ Y | ins | | /| | / | | / | | / o | |/ 0.005 | x---------------> X \ | Z ins \ | ins \ | \ | \| |-- 1.0 --| Plane X = 0 Now from here we see that the Y component of one 'boundary corner' vector is: Y Component = 1.0 * tan ( 0.005 degrees ) = 8.72665D-5 Utilizing the ANGLES FOV specification: \begindata INS-82184_FOV_FRAME = 'CASSINI_LGA1' INS-82184_FOV_SHAPE = 'CIRCLE' INS-82184_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82184_FOV_CLASS_SPEC = 'ANGLES' INS-82184_FOV_REF_VECTOR = ( 0.0000000000000000 +1.0000000000000000 0.0000000000000000 ) INS-82184_FOV_REF_ANGLE = ( 0.005 ) INS-82184_FOV_ANGLE_UNITS = 'DEGREES' \begintext Low Gain Antenna 2 (LGA2) FOV Definition Since the LGA2's FOV is circular and its diameter is 0.010 degrees, looking down the X-axis in the CASSINI_LGA2 frame, we have: (Note we are arbitrarily choosing a vector that terminates in the Z=1 plane.) ^ Y | ins | | /| | / | | / | | / o | |/ 0.005 | x---------------> X \ | Z ins \ | ins \ | \ | \| |-- 1.0 --| Plane X = 0 Now from here we see that the Y component of one 'boundary corner' vector is: Y Component = 1.0 * tan ( 0.005 degrees ) = 8.72665D-5 Utilizing the ANGLES FOV specification: \begindata INS-82185_FOV_FRAME = 'CASSINI_LGA2' INS-82185_FOV_SHAPE = 'CIRCLE' INS-82185_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82185_FOV_CLASS_SPEC = 'ANGLES' INS-82185_FOV_REF_VECTOR = ( 0.0000000000000000 +1.0000000000000000 0.0000000000000000 ) INS-82185_FOV_REF_ANGLE = ( 0.005 ) INS-82185_FOV_ANGLE_UNITS = 'DEGREES' \begintext X Band True (XBAND_TRUE) FOV Definition Since the XBAND_TRUE's FOV is circular and its diameter is 0.55977977 degrees, looking down the X-axis in the CASSINI_XBAND frame, we have: (Note we are arbitrarily choosing a vector that terminates in the Z=1 plane.) ^ Y | ins | | /| | / | | / | | / o | |/ 0.280 | x---------------> X \ | Z ins \ | ins \ | \ | \| |-- 1.0 --| Plane X = 0 Now from here we see that the Y component of one 'boundary corner' vector is: Y Component = 1.0 * tan ( 0.279889885 degrees ) = 0.004885039 Utilizing the ANGLES FOV specification: \begindata INS-82186_FOV_FRAME = 'CASSINI_XBAND_TRUE' INS-82186_FOV_SHAPE = 'CIRCLE' INS-82186_BORESIGHT = ( 0.0000000000000000 0.0000000000000000 +1.0000000000000000 ) INS-82186_FOV_CLASS_SPEC = 'ANGLES' INS-82186_FOV_REF_VECTOR = ( 0.0000000000000000 +1.0000000000000000 0.0000000000000000 ) INS-82186_FOV_REF_ANGLE = ( 0.279889885 ) INS-82186_FOV_ANGLE_UNITS = 'DEGREES' \begintext RSS Pixel Parameters ---------------------------------------------------------- These parameters describe the pixel structure associated with the instruments and their fields of views. In some cases this is a generalization of the notion of pixel, in that instead of representing pixels on a CCD they may represent a collection of individual detectors. KA Band (KABAND): \begindata INS-82180_FOV_CENTER_PIXEL = ( 0, 0 ) INS-82180_PIXEL_SAMPLES = ( 1 ) INS-82180_PIXEL_LINES = ( 1 ) \begintext KU Band (KUBAND): \begindata INS-82181_FOV_CENTER_PIXEL = ( 0, 0 ) INS-82181_PIXEL_SAMPLES = ( 1 ) INS-82181_PIXEL_LINES = ( 1 ) \begintext S Band (SBAND): \begindata INS-82182_FOV_CENTER_PIXEL = ( 0, 0 ) INS-82182_PIXEL_SAMPLES = ( 1 ) INS-82182_PIXEL_LINES = ( 1 ) \begintext X Band (XBAND): \begindata INS-82183_FOV_CENTER_PIXEL = ( 0, 0 ) INS-82183_PIXEL_SAMPLES = ( 1 ) INS-82183_PIXEL_LINES = ( 1 ) \begintext Low Gain Antenna 1 (LGA1): \begindata INS-82184_FOV_CENTER_PIXEL = ( 0, 0 ) INS-82184_PIXEL_SAMPLES = ( 1 ) INS-82184_PIXEL_LINES = ( 1 ) \begintext Low Gain Antenna 2 (LGA2): \begindata INS-82185_FOV_CENTER_PIXEL = ( 0, 0 ) INS-82185_PIXEL_SAMPLES = ( 1 ) INS-82185_PIXEL_LINES = ( 1 ) \begintext X Band True (XBAND_TRUE): \begindata INS-82186_FOV_CENTER_PIXEL = ( 0, 0 ) INS-82186_PIXEL_SAMPLES = ( 1 ) INS-82186_PIXEL_LINES = ( 1 ) \begintext Instrument Mode Timing ---------------------------------------------------------- The following values were provided as samples in [5]. These values are defined in [5] as follows: ``The initial values for the following keywords are given per instrument number: INS[instrument number]_[instrument acronym]_MODE_NAME INS[instrument number]_[instrument acronym]_TRIGGER_OFFSET INS[instrument number]_[instrument acronym]_CYCLE_DURATION INS..._MODE_NAME contains the name of the instrument mode for the INS..._TRIGGER_OFFSET and INS..._CYCLE_DURATION keywords. INS..._TRIGGER_OFFSET specifies the reference time of the first instrument frame (to be calculated for a footprint) relative to the time of transacting the corresponding TRIGGER command. The units are SFOC duration. INS..._CYCLE_DURATION specifies the duration between successive instrument frames (from the first one) for the INS..._MODE_NAME.'' KA Band (KABAND) \begindata INS-82180_MODE_NAME = 'NOMINAL' INS-82180_TRIGGER_OFFSET = '0:01:00.0' INS-82180_CYCLE_DURATION = '0:01:00.0' \begintext KU Band (KUBAND) \begindata INS-82181_MODE_NAME = 'NOMINAL' INS-82181_TRIGGER_OFFSET = '0:01:00.0' INS-82181_CYCLE_DURATION = '0:01:00.0' \begintext S Band (SBAND) \begindata INS-82182_MODE_NAME = 'NOMINAL' INS-82182_TRIGGER_OFFSET = '0:01:00.0' INS-82182_CYCLE_DURATION = '0:01:00.0' \begintext X Band (XBAND) \begindata INS-82183_MODE_NAME = 'NOMINAL' INS-82183_TRIGGER_OFFSET = '0:01:00.0' INS-82183_CYCLE_DURATION = '0:01:00.0' \begintext Low Gain Antenna 1 (LGA1) \begindata INS-82184_MODE_NAME = 'NOMINAL' INS-82184_TRIGGER_OFFSET = '0:01:00.0' INS-82184_CYCLE_DURATION = '0:01:00.0' \begintext Low Gain Antenna 2 (LGA2) \begindata INS-82185_MODE_NAME = 'NOMINAL' INS-82185_TRIGGER_OFFSET = '0:01:00.0' INS-82185_CYCLE_DURATION = '0:01:00.0' \begintext X Band True (XBAND_TRUE) \begindata INS-82186_MODE_NAME = 'NOMINAL' INS-82186_TRIGGER_OFFSET = '0:01:00.0' INS-82186_CYCLE_DURATION = '0:01:00.0' \begintext NAIF ID Code to Name Mapping ---------------------------------------------------------- \begindata NAIF_BODY_NAME += ( 'CASSINI_RSS_HGA_KA' ) NAIF_BODY_CODE += ( -82180 ) NAIF_BODY_NAME += ( 'CASSINI_RSS_HGA_KU' ) NAIF_BODY_CODE += ( -82181 ) NAIF_BODY_NAME += ( 'CASSINI_RSS_HGA_S' ) NAIF_BODY_CODE += ( -82182 ) NAIF_BODY_NAME += ( 'CASSINI_RSS_HGA_X' ) NAIF_BODY_CODE += ( -82183 ) NAIF_BODY_NAME += ( 'CASSINI_RSS_LGA1' ) NAIF_BODY_CODE += ( -82184 ) NAIF_BODY_NAME += ( 'CASSINI_RSS_LGA2' ) NAIF_BODY_CODE += ( -82185 ) NAIF_BODY_NAME += ( 'CASSINI_RSS_HGA_X_TRUE' ) NAIF_BODY_CODE += ( -82186 ) \begintext Platform ID ---------------------------------------------------------- The RSS instruments are mounted on the Cassini Spacecraft body. Therefore the values stored in the keywords below are -82000. \begindata INS-82180_PLATFORM_ID = ( -82000 ) INS-82181_PLATFORM_ID = ( -82000 ) INS-82182_PLATFORM_ID = ( -82000 ) INS-82183_PLATFORM_ID = ( -82000 ) INS-82184_PLATFORM_ID = ( -82000 ) INS-82185_PLATFORM_ID = ( -82000 ) INS-82186_PLATFORM_ID = ( -82000 ) \begintext