urn:nasa:pds:grail_gravity_derived:data_shadr:gggrx_1200b_sha
1.2
GRAIL Gravity ASCII Spherical Harmonic Model: GRGM1200B
1.18.0.0
Product_Observational
2023-05-24
1.2
Updated file comment regarding principal axis frame
2023-02-01
1.1
Updated a description in the SHADR Coefficients Table
2022-08-12
1.0
Initial version
2012-03-01Z
2012-12-14Z
Gravity Recovery and Interior Laboratory
Mission
urn:nasa:pds:context:investigation:mission.gravity_recovery_and_interior_laboratory
data_to_investigation
Gravity Recovery and Interior Laboratory A
Host
urn:nasa:pds:context:instrument_host:spacecraft.grail-a
is_instrument_host
Gravity Recovery and Interior Laboratory B
Host
urn:nasa:pds:context:instrument_host:spacecraft.grail-b
is_instrument_host
Lunar Gravity Ranging System A for GRAIL-A
Instrument
urn:nasa:pds:context:instrument:grail-a.lgrs-a
is_instrument
Lunar Gravity Ranging System B for GRAIL-B
Instrument
urn:nasa:pds:context:instrument:grail-b.lgrs-b
is_instrument
Moon
Satellite
urn:nasa:pds:context:target:satellite.earth.moon
data_to_target
gggrx_1200b_sha.tab
2019-09-17
This file contains coefficients and related data for the GSFC Lunar gravity
field GRGM1200B, a degree and order 1200 Spherical Harmonic Model. It is a
GSFC gravity field that includes the entire GRAIL data set (and that does
not include other data).
Some details describing this model are:
The spherical harmonic coefficients are fully normalized (geodesy 4pi
normalized).
The uncertainties are calibrated (the formal uncertainties multiplied by
a factor of 1.555).
The reference radius = 1738.0 km
The gravitational parameter is GM = 4902.80012244530 km**3/s**2
The planetary ephemeris is de430 and defines the lunar body-fixed
coordinate system in the principal axes frame.
A Kaula type power law constraint is applied to the spherical harmonics
coefficients for degrees greater than 600 (3.6e-4/n^2).
The weighting of the KBRR data is:
0.03 microns/sec in the primary mission
0.05 microns/sec in the extended mission
The weighting of the DSN data is:
0.12mm/s in both the primary and extended mission
The nominal tidal Love number is k2 = 0.024116 +/- 0.000108
The current best reference for the GRGM1200B gravity field is
GOOSSENSETAL2019, submitted to Journal of Geophysical Research: Planets.
For additional details on the GRAIL mission, data and methods see
LEMOINEETAL2013 and LEMOINEETAL2014.
This file is a pair of ASCII tables: a header table and a table of
1442397 coefficients. Definitions of the tables follow.
0
1
The SHADR header includes
descriptive information about the spherical harmonic
coefficients which follow in SHADR_COEFFICIENTS_TABLE.
The header consists of a single record of eight (delimited)
data columns requiring 137 bytes, a pad of 105 unspecified
ASCII characters, an ASCII carriage-return, and an ASCII
line-feed.
Carriage-Return Line-Feed
9
0
244
Reference_Raduis
1
1
ASCII_Real
23
Km
The assumed reference radius of the spherical planet.
Constant
2
25
ASCII_Real
23
For a gravity field model the assumed gravitational
constant GM in kilometers cubed per seconds squared for the
planet. For a topography model, set to 1.
Uncertainty_in_Constant
3
49
ASCII_Real
23
For a gravity field model the uncertainty in the gravitational
constant GM in kilometers cubed per seconds squared for the
planet. For a topography model, set to 1.
Degree_of_Field
4
73
ASCII_Integer
5
The degree of model field.
Order_of_Field
5
79
ASCII_Integer
5
The order of the model field.
Normalization_State
6
85
ASCII_Integer
5
The normalization indicator. For gravity field:
0 coefficients are unnormalized
1 coefficients are normalized
2 other.
Reference_Longitude
7
91
ASCII_Real
23
Degree
The reference longitude for
the spherical harmonic expansion; normally 0.
Reference_Latitude
8
115
ASCII_Real
23
Degree
The reference latitude for
the spherical harmonic expansion; normally 0.
Fill
9
138
ASCII_String
105
SHADR Coefficients Table
244
721800
The SHADR coefficients table
contains the coefficients for the Spherical Harmonic Model.
Each row in the table contains the degree index m, the
order index n, the coefficients Cmn and Smn, and the
uncertainties in Cmn and Smn. The (delimited) data
require 107 ASCII characters; these are followed by a pad
of 13 unspecified ASCII characters, an ASCII carriage-
return, and an ASCII line-feed.
Carriage-Return Line-Feed
7
0
122
COEFFICIENT DEGREE
1
1
ASCII_Integer
5
The degree index m of the C and S coefficients
in this record.
COEFFICIENT ORDER
2
7
ASCII_Integer
5
The order index n of the C and S coefficients
in this record.
C
3
13
ASCII_Real
23
The coefficient Cmn for this spherical harmonic
model.
S
4
37
ASCII_Real
23
The coefficient Smn for this spherical harmonic
model.
C_Uncertainty
5
61
ASCII_Real
23
The uncertainty in the
coefficient Cmn for this Spherical Harmonic Model.
S_Uncertainty
6
85
ASCII_Real
23
The uncertainty in the
coefficient Smn for this Spherical Harmonic Model.
Fill
7
108
ASCII_String
13
A pad of 13 unspecified ASCII characters.
gggrx_1200b_sha.lbl
0
PDS3
Original PDS3 label
Carriage-Return Line-Feed