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| The GNSS SPICE Kernel Dataset |
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Last update: February 24, 2023
Introduction
============
This document describes the GNSS SPICE kernel dataset (SKD)
containing observation geometry and other ancillary data in the form of
SPICE System kernel files for the GNSS spacecraft, its instruments
and targets. It describes the dataset directory structure,
kernels included in the dataset, their naming conventions, and provides
pointers to the SPICE software and documentation.
Table of Contents
=================
Introduction
Table of Contents
Overview
Errata
Archive Contents
Kernel Types
Kernel Details
SPK Files
PCK Files
IK Files
CK Files
DSK Files
LSK Files
SCLK Files
FK Files
MK Files
ORBNUM Files
SKD Latest Release Notes
SPICE Software and Documentation
Contact Information
Overview
========
This archive includes the complete set of GNSS SPICE data files
(kernel files), which can be accessed using SPICE software. The
SPICE data contain geometric and other ancillary information needed
to recover the full value of science instrument data. In particular
SPICE kernels provide spacecraft and planetary ephemeris,
spacecraft and instrument orientation, instrument mounting
alignments, and data needed for relevant time conversions. Data in
the SPICE kernel files must be accessed using the software called
the SPICE Toolkit produced and distributed by the Navigation and
Ancillary Information Facility (NAIF) Node of the Planetary Data
System.
This archive includes data covering from GNSS launch,
through the end time of the latest spacecraft orientation file
supplied in the archive. Until the end of the spacecraft lifespan
this archive will be accumulating with new data added according to
the project archiving plan.
Back to Table of Contents
Errata
======
None.
Back to Table of Contents
SPICE Kernel Dataset Contents
=============================
Files in this archive are organized into a set of subdirectories
below the top-level directory. The following diagram shows the
structure and content of these directories. The directory names are
enclosed in square brackets ([]).
[gnss] Top-level directory
|
|-[kernels] Directory containing SPICE kernels.
| |
| |- aareadme.txt SPICE Kernel Dataset top-level readme file.
| |
| |-[ck] Directory containing CK files.
| | |
| | |-- *.BC Binary CK files.
| | +-- *.txt CK readme file.
| |
| |-[dsk] Directory containing DSK files.
| | |
| | |-- *.BDS Binary DSK files.
| | |-- *.OBJ Geometry definition file generated from a DSK.
| | |-- *.PNG Graphic file from an OBJ file.
| | +-- *.txt DSK readme file.
| |
| |-[fk] Directory containing FK files.
| | |
| | |-- *.TF Text FK files.
| | +-- *.txt FK readme file.
| |
| |-[ik] Directory containing IK files.
| | |
| | |-- *.TI Text IK files.
| | +-- *.txt IK readme file.
| |
| |-[lsk] Directory containing LSK files.
| | |
| | |-- *.TLS Text LSK files.
| | +-- *.txt LSK readme file.
| |
| |--[mk] Directory containing MK files.
| | |
| | |-- *.TM Text Meta-kernel files.
| | +-- *.txt MK readme file.
| |
| |--[orbnum] Directory containing ORBNUM files.
| | |
| | |-- *.ORBNUM Text ORBNUM files.
| | +-- *.txt ORBNUM readme file.
| |
| |-[pck] Directory containing PCK files.
| | |
| | |-- *.TPC Text PCK files.
| | |-- *.BPC Binary PCK files.
| | +-- *.txt PCK readme file.
| |
| |-[sclk] Directory containing SCLK files.
| | |
| | |-- *.TSC Text SCLK files.
| | +-- *.txt SCLK readme file.
| |
| +-[spk] Directory containing SPK files.
| |
| |-- *.BSP Binary SPK files.
| +-- *.txt SPK readme file.
|
+-[misc] Directory containing miscellaneous documents.
|
|-[release_notes] Directory containing release notes.
| |
| +-- *.txt Release notes files.
|
|-[cosmo] Directory containing SPICE-Enhanced
| | Cosmographia configuration files.
| |
| |-[config] Directory containing configuration files
| | | for the spacecraft(s) and the SPICE kernels used.
| | |
| | +-- *.json JSON configuration files.
| |
| |-[models] Directory containing 3D models for the spacecraft(s).
| | |
| | |-- *.3ds 3D Studio models.
| | |-- *.cmod Celestia models.
| | +-- *.jpg Texture for the models
| |
| |-[observations] Directory containing observations.
| | |
| | +-- *.json JSON observation files.
| |
| |-[scenarios] Directory containing scenarios definitions.
| | |
| | +-- *.json JSON scenario files.
| |
| |-[sensors] Directory containing sensor configurations.
| | |
| | +-- *.json JSON sensor files.
| |
| +-[scripts] Directory containing scripts.
| |
| |-- *.py Python files.
| |-- *.csh Bash files for Unix/MAC.
| +-- *.bat Batch files for Windows.
|
|-[deprecated_kernels] Directory that replicates the kernels
| directory with deprecated kernels.
|
|-[skd] Directory that contains a zipped directory
| | with the latest sub-set of the
| | SPICE Kernel Dataset from the meta-kernels
| |
| +-- *.zip Zipped directory.
|
+-gnss.html This file.
Back to Table of Contents
Kernel Types
============
Different SPICE kernel types are used to store different kinds of
ancillary data.
SPK (Spacecraft Planet Kernel) files contain ephemerides (position
and velocity) for spacecraft, planets, satellites, comets and
asteroids as well as for moving or fixed spacecraft and instrument
structures. SPK files are located under the kernels/spk
directory of this archive.
PCK (Planetary Constants Kernel) files contain certain physical,
dynamical and cartographic constants for target bodies, such as size
and shape specifications, and orientation of the spin axis and prime
meridian. PCK files are located under the kernels/pck
directory of this archive.
IK (Instrument Kernel) files contain instrument parameters relevant
for computing an instrument's geometry such as field-of-view
definitions, CCD and optical distortion characteristics, and internal
timing parameters. IK files are located under the kernels/ik
directory of this archive.
CK (C-matrix Kernel) files contain time varying orientations for
spacecraft, spacecraft structures, and articulating science
instruments. CK files are located under the kernels/ck
directory of this archive.
DSK (Digital Shape Kernel) files contain detailed shape models for
extended objects. These objects typically are solar system bodies such as
planets, dwarf planets, natural satellites, asteroids, and comet nuclei. DSK
data can represent the shapes of such objects, as well as local topography,
such as that in the vicinity of a rover or a tracking station. DSK data also
can represent shapes of artificial objects such as spacecraft components, or
represent abstractions such as the subset of a target body's surface that
has a property of interest. DSK files are located under the kernels/dsk
directory of this archive.
LSK (Leapseconds Kernel) files contain the leapseconds and the
values of other constants required to perform a transformation
between Universal Time Coordinated (UTC) and Ephemeris time (ET),
which is also known as Barycentric Dynamical Time (TDB). LSK
files are located under the kernels/lsk directory of
this archive.
SCLK (Spacecraft Clock Kernel) files contain on-board clock
calibration data required to perform a transformation between
Ephemeris time (ET) and spacecraft on-board time (SCLK). SCLK files
are located under the kernels/sclk directory of this
archive.
FK (Frame definitions Kernel) files contain information required to
define reference frames, sources of frame orientation data and
connections between these frames and other frames supported within
the SPICE system. The science instrument frame definitions provided
in the FK files include mounting alignment information for the
instruments. FK files are located under the kernels/fk
directory of this archive.
MK (Meta-Kernel) files list sets of related SPICE kernels that
should be used together, providing an easy way to make data from
these kernel sets available to a SPICE-based application by loading
meta-kernels into the program using the high level SPICE data loader
routine FURNSH. MK files are located the kernels/mk
directory of this archive.
Kernel Details
==============
The subsections below provide details, such as file naming
conventions and specific details, for each of the kernel types
included in this archive.
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SKD Latest Release Notes
========================
This section provides the latest release notes of the GNSS
SPICE Kernel Dataset
Back to Table of Contents
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SPICE Software and Documentation
================================
The latest SPICE Toolkit for a variety of computer platforms,
additional utility programs, documentation, tutorials, and hands-on
lessons are available at the NAIF Node of the PDS:
http://naif.jpl.nasa.gov
specifically:
Toolkit: http://naif.jpl.nasa.gov/naif/toolkit.html
Utilities: http://naif.jpl.nasa.gov/naif/utilities.html
Tutorials: http://naif.jpl.nasa.gov/naif/tutorials.html
Lessons: http://naif.jpl.nasa.gov/naif/lessons.html
Back to Table of Contents
Contact Information
===============================
If you have any questions regarding this file contact the
ESA SPICE Service (ESS) at ESAC:
Alfredo Escalante Lopez
(+34) 91-8131-429
spice@sciops.esa.int
End of GNSS SPICE Kernel Dataset description.
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