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Earth Orientation Parameters

Calculate Earth orientation parameters (EOP)

  • Library:
  • Aerospace Blockset / Environment / Celestial Phenomena

Description

The Earth Orientation Parameters block calculates these parameters:

  • Difference between the UTC and Universal Time (UT1)

  • Movement of the rotation axis with respect to the crust of the Earth

  • Adjustment to the location of the Celestial Intermediate Pole (CIP)

By default, this block uses a prepopulated list of International Earth Rotation and Reference Systems Service (IERS) data. This list contains measured and calculated (predicted) data supplied by the IERS. The IERS measures and calculates this data for a set of predetermined dates. For dates after those listed in the prepopulated list, Earth Orientation Parameters calculates the ΔUT1 using this equation, limiting the values to +/- 0.9 s:

UT1-UTC=0.5309-0.00123(MJD-57808)-(UT2-UT1) 

Use this block when your application uses Earth Centered Inertial to Earth Centered Earth Fixed transformations, such as for high altitude applications.

Ports

Input

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UT1 for UTC, specified as a scalar modified Julian date. Use the Julian Date Conversion block to convert the UTC date to a modified Julian date.

Data Types: double

Output

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Difference between UT1 and UTC, specified as a scalar, in seconds.

Data Types: double

Polar displacement of the Earth, [xp,yp], specified as a vector, in radians, from the motion of the Earth crust, along the x- and y-axes.

Data Types: double

Adjustment to the location of the Celestial Intermediate Pole (CIP), specified as a vector, in radians. This location ([dX,dY]) is along the x- and y-axes.

Data Types: double

Return errors for the measured and predicted values in the IERS data for the difference between UT1 and UTC, specified as a vector, in seconds.

Dependencies

This port is enabled when the Output parameter error is selected.

Return errors for the measured and predicted values in the IERS data for the polar displacement of Earth, specified as a vector, in radians.

Dependencies

This port is enabled when the Output parameter error is selected.

Return errors for the measured and predicted values in the IERS data for the adjustment to location of Celestial Intermediate Pole (CIP), specified as a vector, in radians.

Dependencies

This port is enabled when the Output parameter error is selected.

Parameters

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Custom list of Earth orientation data, specified in a MAT-file.

Programmatic Use

Block Parameter: FileName
Type: character vector
Values: scalar
Default: 'aeroiersdata.mat'

Select this parameter to enable output ports to return errors for the measured and predicted values in the IERS data file:

  • Difference between UT1 and UTC

  • Polar displacement of Earth

  • Adjustment to location of Celestial Intermediate Pole (CIP)

Dependencies

Selecting this check box enables these ports:

  • ΔUT1err

  • [xp,yp]err

  • [dX,dY]err

Programmatic Use

Block Parameter: OutputError
Type: character vector
Values: scalar
Default: 'off'

Out-of-range action, specified as a string.

Action to take in case of out-of-range or predicted value dates, specified as a string:

  • Warning — Displays warning and indicates that the dates were out-of-range or predicted values.

  • Error — Displays error and indicates that the dates were out-of-range or predicted values.

  • None — Does not display warning or error.

Programmatic Use

Block Parameter: FileName
Type: character vector
Values: 'Warning' | 'Error' | 'None'
Default: 'Warning'

Website or Earth orientation data file containing the Earth orientation data according to the IAU 2000A, specified as a website address or file name.

Programmatic Use

Block Parameter: FileName
Type: character vector
Values: scalar
Default: 'aeroiersdata.mat'

Folder for IERS data file, specified as a character array or string. Before running this function, create foldername with write permission.

To create the IERS data file in the destination folder, click the Create button.

Programmatic Use

Block Parameter: FileName
Type: character vector
Values: scalar
Default: 'aeroiersdata.mat'

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Introduced in R2018b