<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<?xml-model href="https://pds.nasa.gov/pds4/pds/v1/PDS4_PDS_1I00.sch" schematypens="http://purl.oclc.org/dsdl/schematron"?>

<Product_Observational xmlns="http://pds.nasa.gov/pds4/pds/v1" 
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
  xsi:schemaLocation="http://pds.nasa.gov/pds4/pds/v1 https://pds.nasa.gov/pds4/pds/v1/PDS4_PDS_1I00.xsd">
  <Identification_Area>
    <logical_identifier>urn:nasa:pds:grail_gravity_derived:data_shbdr:jggrx_0900d_shb_l900</logical_identifier>
    <version_id>1.0</version_id>
    <title>GRAIL Gravity Binary Spherical Harmonic Model: jggrx_0900d_shb_l900</title>
    <information_model_version>1.18.0.0</information_model_version>
    <product_class>Product_Observational</product_class>
    <Modification_History>
      <Modification_Detail>
        <modification_date>2022-08-16</modification_date>
        <version_id>1.0</version_id>
        <description>Initial PDS4 version</description>
      </Modification_Detail>
    </Modification_History>
  </Identification_Area>
  <Observation_Area>
    <Time_Coordinates>
      <start_date_time>2012-03-01T16:28:00.000Z</start_date_time>
      <stop_date_time>2012-12-14T20:56:00.000Z</stop_date_time>
    </Time_Coordinates>
    <Investigation_Area>
      <name>Gravity Recovery and Interior Laboratory</name>
      <type>Mission</type>
      <Internal_Reference>
        <lid_reference>urn:nasa:pds:context:investigation:mission.gravity_recovery_and_interior_laboratory</lid_reference>
        <reference_type>data_to_investigation</reference_type>
      </Internal_Reference>
    </Investigation_Area>
    <Observing_System>
      <Observing_System_Component>
        <name>Gravity Recovery and Interior Laboratory A</name>
        <type>Host</type>
        <Internal_Reference>
          <lid_reference>urn:nasa:pds:context:instrument_host:spacecraft.grail-a</lid_reference>
          <reference_type>is_instrument_host</reference_type>
        </Internal_Reference>
      </Observing_System_Component>
      <Observing_System_Component>
        <name>Gravity Recovery and Interior Laboratory B</name>
        <type>Host</type>
        <Internal_Reference>
          <lid_reference>urn:nasa:pds:context:instrument_host:spacecraft.grail-b</lid_reference>
          <reference_type>is_instrument_host</reference_type>
        </Internal_Reference>
      </Observing_System_Component>
      <Observing_System_Component>
        <name>Lunar Gravity Ranging System A for GRAIL-A</name>
        <type>Instrument</type>
        <Internal_Reference>
          <lid_reference>urn:nasa:pds:context:instrument:grail-a.lgrs-a</lid_reference>
          <reference_type>is_instrument</reference_type>
        </Internal_Reference>
      </Observing_System_Component>
      <Observing_System_Component>
        <name>Lunar Gravity Ranging System B for GRAIL-B</name>
        <type>Instrument</type>
        <Internal_Reference>
          <lid_reference>urn:nasa:pds:context:instrument:grail-b.lgrs-b</lid_reference>
          <reference_type>is_instrument</reference_type>
        </Internal_Reference>
      </Observing_System_Component>
    </Observing_System>
    <Target_Identification>
      <name>Moon</name>
      <type>Satellite</type>
      <Internal_Reference>
        <lid_reference>urn:nasa:pds:context:target:satellite.earth.moon</lid_reference>
        <reference_type>data_to_target</reference_type>
      </Internal_Reference>
    </Target_Identification>
  </Observation_Area>
  <File_Area_Observational>
    <File>
      <file_name>jggrx_0900d_shb_l900.dat</file_name>
      <creation_date_time>2013-11-06T00:00:00.000</creation_date_time>
      <comment>
        This file contains coefficients and related data for the JPL Lunar gravity
        field GL0900D, a 900th degree and order spherical harmonic model. It is a
        JPL gravity field that includes the entire Primary Mission
        (March 1, 16:30 to May 29, 16:36, 2012) and the entire Extended Mission of
        GRAIL tracking data (August 30, 16:20 to Dec. 14, 20:56, 2012). This
        solution uses the version 3 level-1 data for both the primary mission and
        extended mission.
        
        Some details describing this model are:
        The spherical harmonic coefficients are fully normalized.
        The reference radius = 1738.0 km
        The planetary ephemeris is de430 and defines the lunar body-fixed
        coordinate system.
        A power law constraint (1/n^1/2) is applied starting at n=701.
        
        The weighting of the KBRR data is 0.03 to 0.06 microns/sec for the
        primary mission and 0.05 microns/sec for the extended mission except
        the data from Nov. 19 to Dec. 14 is weighted near 0.2 microns/sec.
        
        The second degree Love number solution is fixed to k2=0.0239.
        The second degree gravity coefficients of this model do not include
        the permanent tide.
        
        This product contains the full covariance of the GL0900D
        gravity model or JGGRX_0900D_SHA.
        
        The reference for the GL0900D gravity field is KONOPLIVETAL2014,
        published in Geophysical Research Letters with the DOI number
        10.1002/2013GL059066.
        
        This product is a set of binary tables:
        a header table, a names table, a coefficients table, and a covariance
        table. Definitions of the tables follow. This GRAIL moon gravity model
        is in the form of a Spherical Harmonics Binary Data Record (SHBDR).
      </comment>
    </File>
    <Table_Binary>
      <name>SHBDR_Header_Table</name>
      <offset unit="byte">0</offset>
      <records>1</records>
      <description>The SHBDR Header includes descriptive information about the spherical
        harmonic coefficients that follow in SHBDR_Coefficients_Table. The header consists
        of a single record of nine data columns requiring 56 bytes. The Header is followed by
        a pad of binary integer zeroes.</description>
      <Record_Binary>
        <fields>9</fields>
        <groups>0</groups>
        <record_length unit="byte">56</record_length>
        <Field_Binary>
          <name>Reference_Radius</name>
          <field_number>1</field_number>
          <field_location unit="byte">1</field_location>
          <data_type>IEEE754LSBDouble</data_type>
          <field_length unit="byte">8</field_length>
          <unit>km</unit>
          <description>The assumed reference radius of the spherical planet.</description>
        </Field_Binary>
        <Field_Binary>
          <name>Constant</name>
          <field_number>2</field_number>
          <field_location unit="byte">9</field_location>
          <data_type>IEEE754LSBDouble</data_type>
          <field_length unit="byte">8</field_length>
          <description>For a gravity field model
            the gravitational constant GM in km cubed per second
            squared for the planet. For a topography model, set to 1.
          </description>
        </Field_Binary>
        <Field_Binary>
          <name>Uncertainty_in_Constant</name>
          <field_number>3</field_number>
          <field_location unit="byte">17</field_location>
          <data_type>IEEE754LSBDouble</data_type>
          <field_length unit="byte">8</field_length>
          <description>For a gravity field model the uncertainty in the 
            gravitational constant GM in km cubed per second squared for
            the planet. For a topography model, set to 0.</description>
        </Field_Binary>
        <Field_Binary>
          <name>Degree_of_Field</name>
          <field_number>4</field_number>
          <field_location unit="byte">25</field_location>
          <data_type>SignedLSB4</data_type>
          <field_length unit="byte">4</field_length>
          <description>Degree of the model field.</description>
        </Field_Binary>
        <Field_Binary>
          <name>Order_of_Field</name>
          <field_number>5</field_number>
          <field_location unit="byte">29</field_location>
          <data_type>SignedLSB4</data_type>
          <field_length unit="byte">4</field_length>
          <description>Order of the model field.</description>
        </Field_Binary>
        <Field_Binary>
          <name>Normalization_State</name>
          <field_number>6</field_number>
          <field_location unit="byte">33</field_location>
          <data_type>SignedLSB4</data_type>
          <field_length unit="byte">4</field_length>
          <description>The normalization indicator. For gravity field:
            0   coefficients are unnormalized
            1   coefficients are normalized
            2   other.</description>
        </Field_Binary>
        <Field_Binary>
          <name>Number_of_Names</name>
          <field_number>7</field_number>
          <field_location unit="byte">37</field_location>
          <data_type>SignedLSB4</data_type>
          <field_length unit="byte">4</field_length>
          <description>Number of valid names in
            the SHBDR_Names_Table. Also, the number of valid
            coefficients in the SHBDR_Coefficients_Table.</description>
        </Field_Binary>
        <Field_Binary>
          <name>Reference_Longitude</name>
          <field_number>8</field_number>
          <field_location unit="byte">41</field_location>
          <data_type>IEEE754LSBDouble</data_type>
          <field_length unit="byte">8</field_length>
          <unit>degree</unit>
          <description>Reference longitude for the spherical harmonic 
            expansion; normally 0.</description>
        </Field_Binary>
        <Field_Binary>
          <name>Reference_Latitude</name>
          <field_number>9</field_number>
          <field_location unit="byte">49</field_location>
          <data_type>IEEE754LSBDouble</data_type>
          <field_length unit="byte">8</field_length>
          <unit>degree</unit>
          <description>Reference latitude for the spherical harmonic
            expansion; normally 0.</description>
        </Field_Binary>
      </Record_Binary>
    </Table_Binary>
    
    <Table_Binary>
      <name>SHBDR_Names_Table</name>
      <offset unit="byte">512</offset>
      <records>811798</records>
      <description>
        The SHBDR_Names_Table contains names for the solution parameters (including
        gravity field coefficients) which will follow in SHBDR_Coefficients_Table.
        The order of the names in SHBDR_Names_Table corresponds identically to the
        order of the parameters in SHBDR_Coefficients_Table. Each coefficient name
        is of the form Cij or Sij where i is the degree of the coefficient and j is 
        the order of the coefficient. Both indices are three-digit zero-filled
        right-justified ASCII character strings (for example, C010005 for the 10th
        degree 5th order C coefficient, or S002001 for the 2nd degree 1st order
        S coefficient). The eighth byte in the table is an ASCII blank used to ensure
        that the row length is equal to 8 bytes. Names of other solution parameters are
        limited to 8 ASCII characters; if less than 8, they will be left-justified and
        padded with ASCII blanks. The Names Table itself will be padded with ASCII blanks,
        if necessary.</description>
      <Record_Binary>
        <fields>1</fields>
        <groups>0</groups>
        <record_length unit="byte">8</record_length>
        <Field_Binary>
          <name>Parameter_Name</name>
          <field_number>1</field_number>
          <field_location unit="byte">1</field_location>
          <data_type>ASCII_String</data_type>
          <field_length unit="byte">8</field_length>
          <description>The name of the coefficient or other solution parameter, 
            left-justified and padded with ASCII blanks (if needed) to 8 
            characters.</description>
        </Field_Binary>
      </Record_Binary>
    </Table_Binary>
    
    <Table_Binary>
      <name>SHBDR_Coefficients_Table</name>
      <offset unit="byte">6495232</offset>
      <records>811798</records>
      <description>The SHBDR_Coefficients_Table contains the coefficients and other
        solution parameters for the spherical harmonic model. The order of the 
        coefficients in this table corresponds exactly to the order of the coefficient
        and parameter names in SHBDR_Names_Table. The SHBDR_Coefficients_Table will be
        padded with double precision zeroes.</description>
      <Record_Binary>
        <fields>1</fields>
        <groups>0</groups>
        <record_length unit="byte">8</record_length>
        <Field_Binary>
          <name>Coefficient_Value</name>
          <field_number>1</field_number>
          <field_location unit="byte">1</field_location>
          <data_type>IEEE754LSBDouble</data_type>
          <field_length unit="byte">8</field_length>
          <description>A coefficient Cij or Sij or other solution parameter as specified
            in the SHBDR_Names_Table.</description>
        </Field_Binary>
      </Record_Binary>
    </Table_Binary>
    
    <Table_Binary>
      <name>SHBDR_Covariance_Table</name>
      <offset unit="byte">12989952</offset>
      <records>329508402301</records>
      <description>The SHBDR_Covariance_Table
        contains the covariances for the spherical harmonic model
        coefficients and other solution parameters. The order of
        the covariances in this table is defined as columnwise
        vector storage of the upper triangular matrix formed by
        the product of the SHBDR Names Table with its transpose.
        For example, if the Names Table has four entries  A, B, 
        C, and D,  then the covariances are given by the column 
        vectors in the upper triangular matrix of:
        | A | [ A B C D ] = | AA AB AC AD |
        | B |               | BA BB BC BD |
        | C |               | CA CB CC CD |
        | D |               | DA DB DC DD |
        
        That is, the covariance table will list (in this order)
        AA, AB, BB, AC, BC, CC, AD, BD, CD, and DD.
        The SHBDR_Covariance_Table will be padded with double
        precision zeroes</description>
      <Record_Binary>
        <fields>1</fields>
        <groups>0</groups>
        <record_length unit="byte">8</record_length>
        <Field_Binary>
          <name>Covariance_Value</name>
          <field_number>1</field_number>
          <field_location unit="byte">1</field_location>
          <data_type>IEEE754LSBDouble</data_type>
          <field_length unit="byte">8</field_length>
          <description>The covariance value for the coefficients and other 
            solution parameters specified by the product of SHBDR_Names_Table
            with its transpose, after omitting redundant terms.</description>
        </Field_Binary>
      </Record_Binary>
    </Table_Binary>
  </File_Area_Observational>
  
  <File_Area_Observational_Supplemental>
    <File>
      <file_name>jggrx_0900d_shb_l900.lbl</file_name>
    </File>
    <Stream_Text>
      <offset unit="byte">0</offset>
      <parsing_standard_id>PDS3</parsing_standard_id>
      <description>Original PDS3 label</description>
      <record_delimiter>Carriage-Return Line-Feed</record_delimiter>
    </Stream_Text>
  </File_Area_Observational_Supplemental>
</Product_Observational>
