Lunar Reconnaissance Orbiter SPK files, University of Bonn
**************************************************************************************
Author: Anno Löcher
Institute of Geodesy and Geoinformation
Nussallee 17
D-53115 Bonn
Date of this file: 21 August 2017
Revision: 5 September 2017 (reference to PHASES.txt)
14 February 2018 (solutions added: 10.5 days radio and 2.5 days radio + laser)
Content and usage
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This directory contains orbit data for the Lunar Reconnaissance Orbiter (LRO) for
use with the Spice software system (https://naif.jpl.nasa.gov/naif/). The Spice ID
for LRO is -85. The orbits should be used together with the lunar ephemeris from
DE421.
The orbits are provided in different flavours characterized by the arc length and
the observation types used in the determination of the orbit. Each solution is
stored in a separate subdirectory. Currently, the following solutions are provided:
==================================================================================
Subdirectory | Arc length | Observation types | Mean overlap
| | | error
==================================================================================
LRO_IGG_2.5d_DT_210817 | 2.5 days | Doppler ranges + | 2.81 m
| | two-way ranges |
----------------------------|---------------|-------------------------------------
LRO_IGG_4.5d_DT_210817 | 4.5 days | Doppler ranges + | 2.21 m
| | two-way ranges |
----------------------------|---------------|-------------------------------------
LRO_IGG_6.5d_DT_210817 | 6.5 days | Doppler ranges + | 2.15 m
| | two-way ranges |
----------------------------|---------------|-------------------------------------
LRO_IGG_8.5d_DT_210817 | 8.5 days | Doppler ranges + | 1.99 m
| | two-way ranges |
----------------------------|---------------|-------------------------------------
LRO_IGG_10.5d_DT_130218 | 10.5 days | Doppler ranges + | 2.13 m
| | two-way ranges |
----------------------------|---------------|-------------------------------------
LRO_IGG_2.5d_DTL_130218 | 2.5 days | Doppler ranges + | 2.74 m
| | two-way ranges + |
| | laser ranges |
----------------------------|---------------|-------------------------------------
Each subdirectory contains 64 SPK kernels covering in total the period from 23 June
2009 to 9 September 2014 corresponding to the mission phases Commissioning Orbit
(CO), Nominal Orbit (NO), Science Mission (SM) and the first two years of the
Extended Science Mission (ES). The periods covered by the single kernels correspond
to the mission subphases as defined and used by NASA. The mission subphase is
indicated in the file name after the leading "LRO_IGG". For the start and end times
of mission subphases see the file PHASES.txt.
Short description
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The orbits in this directory were produced from tracking data from the LRO ground
network retrieved from the Planetary Data System (http://pds-geosciences.wustl.edu/).
The orbit determination was performed using an independent software which applies
the variational equations approach. The dynamical modelling is based on the GRAIL
gravity field model GL0900D truncated at degree 400. The solar radiation pressure
was modelled using a spacecraft 3-D model accounting for the effects of
self-shadowing and a model for the lunar albedo force. The parameter set estimated
for each arc included a scale factor for solar radiation and a piecewise linear
acceleration in along-track direction. For the details of data processing see the
publication in the "Reference" section.
For the orbit computation, the data were processed in overlapping arcs. The orbits
in the SPK kernels were assembled from several such arcs with linear transitions
in the overlap periods. The state vectors from the orbit integration were converted
to the SPK data type 9 (Lagrange interpolation, unequal time steps, polynomial
degree 9).
Reference
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When using these orbits please cite:
A Löcher, J Kusche (2017): Precise orbits of the Lunar Reconnaissance Orbiter from
radiometric tracking data. Submitted to Journal of Geodesy
Acknowledgement
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The orbits in this directory were computed at the University of Bonn in the
framework of the research unit FOR 1503 "Space-Time Reference Systems for
Monitoring Global Change and for Precise Navigation in Space" funded by the German
Research Foundation (DFG).
Contact
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If you have any questions regarding these orbits please contact:
Anno Löcher
Institute of Geodesy and Geoinformation
Nussallee 17
D-53115 Bonn
loecher@geod.uni-bonn.de