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Unmanned Spaceflight.com _ Cassini PDS _ Which SPICE kernels?

Posted by: adamg Nov 14 2021, 01:17 AM

I see SPICE kernels in two different places:

https://naif.jpl.nasa.gov/pub/naif/CASSINI/kernels/
https://naif.jpl.nasa.gov/pub/naif/pds/data/co-s_j_e_v-spice-6-v1.0/cosp_1000/data/

They don't match up, does anyone know which would be the recommended set to look at?

Many thanks

Posted by: JohnVV Nov 14 2021, 04:57 AM

as i understand the kernels in the "pds" subdirectory are older

use
https://naif.jpl.nasa.gov/pub/naif/CASSINI/kernels/

Posted by: adamg Nov 14 2021, 08:30 AM

Awesome, thanks.

Posted by: adamg Jan 9 2022, 03:55 PM

I'm running through the images to figure out what's what and I'm stuck when I get to image N1875522952_1 in the extended_extended set.

The image is taken at spacecraft clock 11875522951.118 (the .LBL file suggests this is 08/06/2017at 09:26 however SPICE suggests 07/06/2017 09:28, I'm using this) and I tried loading the following positional kernels which I picked out as the latest versions of PE,SK and SCPSE types of SPK kernels with .LBL date spans that cover the spacecraft clock time:
170619AP_PE_17166_17258.bsp
170619AP_SK_17166_17258.bsp
200128RU_SCPSE_17126_17158.bsp

When I try to get the position (spice.spkpos('Cassini', et, 'J2000', 'NONE', 'SATURN')) I get the following message suggesting I'm not loading the right position kernels.

================================================================================

Toolkit version: CSPICE66

SPICE(SPKINSUFFDATA) --

Insufficient ephemeris data has been loaded to compute the position of -82 (CASSINI) relative to 699 (SATURN) at the ephemeris epoch 2017 JUN 07 09:28:08.127.

spkpos_c --> SPKPOS --> SPKEZP --> SPKGPS

================================================================================

What SPK kernels would you expect for this time point?

Just for completeness the other kernels I'm using are (though I probably only need LSK and SCLK for this query):
LSK (leap seconds) : naif0012.tls.pc
SCLK (spacecraft clock) : cas00172.tsc
PCK (planetary constants) : cpck15Dec2017.tpc
FK (reference frames) : cas_v39.tf
IK (instrument geometry) : cas_iss_v10.ti [Imaging Sub System only]

Many thanks

Adam

Posted by: adamg Mar 12 2022, 11:33 PM

I'm perhaps asking too soon but I'm seeing the artifacts on the attached image of about code 500 and 0. I tried all the endian-ness and signed-ness but this is the least bad of them.

I was just wondering if anyone else had made the same mistake as me?

Many thanks

Adam

This image is from the label file https://pds-imaging.jpl.nasa.gov/w10n/cassini/cassini_orbiter/coiss_2045/data/1592131717_1592134166/N1592133518_1.LBL
and is named N1592133518_1.IMG
the vicar header is below and there is only one segment per line:
{'LBLSIZE': '3216', 'FORMAT': 'HALF', 'TYPE': 'IMAGE', 'BUFSIZ': '20480', 'DIM': '3', 'EOL': '0', 'RECSIZE': '536', 'ORG': 'BSQ', 'NL': '256', 'NS': '256', 'NB': '1', 'N1': '256', 'N2': '256', 'N3': '1', 'N4': '0', 'NBB': '24', 'NLB': '1', 'HOST': 'MAC-OSX', 'INTFMT': 'HIGH', 'REALFMT': 'IEEE', 'BHOST': 'SUN-SOLR', 'BINTFMT': 'HIGH', 'BREALFMT': 'IEEE', 'BLTYPE': 'CAS-ISS4', 'PROPERTY': 'COMPRESSION', 'ANTIBLOOMING_STATE_FLAG': 'OFF', 'CALIBRATION_LAMP_STATE_FLAG': 'N/A', 'DELAYED_READOUT_FLAG': 'NO', 'DETECTOR_TEMPERATURE': '-89.3184', 'EXPOSURE_DURATION': '40.0', 'FILTER_NAME': '(CL1,CL2)', 'FILTER_TEMPERATURE': '0.248629', 'FLIGHT_SOFTWARE_VERSION_ID': '1.4', 'GAIN_MODE_ID': '29 ELECTRONS PER DN', 'INSTRUMENT_DATA_RATE': '365.568', 'INSTRUMENT_MODE_ID': 'SUM4', 'LIGHT_FLOOD_STATE_FLAG': 'ON', 'METHOD_DESC': 'ISSPT2.6.6;Saturn-Rings;ISS_072RI_SPKHRLPDF001_PRIME_2', 'OPTICS_TEMPERATURE': '(0.627499,1.90571)', 'PREPARE_CYCLE_INDEX': '0', 'READOUT_CYCLE_INDEX': '13', 'SENSOR_HEAD_ELEC_TEMPERATURE': '2.34917', 'SHUTTER_MODE_ID': 'NACONLY', 'SHUTTER_STATE_ID': 'ENABLED', 'BIAS_STRIP_MEAN': '145.571', 'DARK_STRIP_MEAN': '97.561', 'DATA_CONVERSION_TYPE': '12BIT', 'MISSING_LINES': '0', 'COMMAND_FILE_NAME': 'trigger_6676_2.ioi', 'COMMAND_SEQUENCE_NUMBER': '6676', 'ELECTRONICS_BIAS': '112', 'ORDER_NUMBER': '66', 'PARALLEL_CLOCK_VOLTAGE_INDEX': '9', 'DATA_SET_ID': 'CO-S-ISSNA/ISSWA-2-EDR-V1.0', 'DESCRIPTION': 'N/A', 'IMAGE_MID_TIME': '2008-166T10:40:49.626Z', 'IMAGE_NUMBER': '1592133518', 'IMAGE_OBSERVATION_TYPE': 'SCIENCE', 'IMAGE_TIME': '2008-166T10:40:49.646Z', 'INSTRUMENT_HOST_NAME': 'CASSINI ORBITER', 'INSTRUMENT_ID': 'ISSNA', 'INSTRUMENT_NAME': 'IMAGING SCIENCE SUBSYSTEM NARROW ANGLE', 'MISSION_NAME': 'CASSINI-HUYGENS', 'MISSION_PHASE_NAME': 'TOUR', 'OBSERVATION_ID': 'ISS_072RI_SPKHRLPDF001_PRIME', 'PRODUCT_CREATION_TIME': '2008-167T02:39:52.000', 'PRODUCT_ID': '1_N1592133518.118', 'PRODUCT_VERSION_TYPE': 'FINAL', 'SEQUENCE_ID': 'S41', 'SEQUENCE_NUMBER': '1004', 'SEQUENCE_TITLE': '--', 'SPACECRAFT_CLOCK_CNT_PARTITION': '1', 'SPACECRAFT_CLOCK_START_COUNT': '1592133518.108', 'SPACECRAFT_CLOCK_STOP_COUNT': '1592133518.118', 'START_TIME': '2008-166T10:40:49.606Z', 'STOP_TIME': '2008-166T10:40:49.646Z', 'TARGET_DESC': 'Saturn-Rings', 'TARGET_LIST': 'N/A', 'TARGET_NAME': 'SATURN', 'EARTH_RECEIVED_START_TIME': '2008-166T23:12:32.754Z', 'EARTH_RECEIVED_STOP_TIME': '2008-166T23:12:35.797Z', 'EXPECTED_PACKETS': '64', 'MISSING_PACKET_FLAG': 'NO', 'RECEIVED_PACKETS': '46', 'SOFTWARE_VERSION_ID': 'ISS 11.00 05-24-2006', 'TELEMETRY_FORMAT_ID': 'S&ER5', 'EXPECTED_MAXIMUM': '(3.95186,69.7116)', 'INST_CMPRS_PARAM': '(N/A,N/A,N/A,N/A)', 'INST_CMPRS_RATE': '(6.95652,4.85864)', 'INST_CMPRS_RATIO': '3.2931', 'INST_CMPRS_TYPE': 'LOSSLESS', 'VALID_MAXIMUM': '(6250,4095)', 'TASK': 'COPY', 'USER': 'diehl', 'DAT_TIM': 'Mon Mar 16 16:39:55 2009'}

Posted by: JohnVV Mar 13 2022, 12:25 AM

isis4 is importing the file file

there is a lot of noise in the image . Noise that i would remove using Gmic ( after exporting to a tiff )

Posted by: adamg Mar 13 2022, 11:06 PM

Thankyou for sending a reference, in the end I tracked it down to me being a byte off so the upper word for each pixel was for the pixel before.

Once I got it working I don't see the noise that you have so I think the underlying image is clean.

Thanks again.

Adam

Posted by: adamg Mar 16 2022, 10:35 PM

I swapped out the WAC red channel for a NIR and the blue for Violet and get the attached image that shows the rings up. I saw some mention of the reflective material identification in the Porco paper but not much. Is there a reference for what each material might give off?

Thanks

Adam

Posted by: adamg Mar 30 2022, 09:21 AM

Thought I'd try out the moon images to set the filter balances. I tried a difference image between LUNAR_SCIENCE (CL1,UV3) and 0.8*(CL1,IR1) and get the attached, the white spots are interesting and show more detail than just the brightness.

A linear scaling doesn't get a flat difference over the moon surface and adding an offset just falls out into a constant, I'm guessing there's some non-linearity I'm missing...