FileEOPProvider¶

Load Earth Orientation Parameters from IERS data files.

FileEOPProvider ¶

FileEOPProvider()

File-based Earth Orientation Parameter provider.

Loads EOP data from files in standard IERS formats and provides interpolation and extrapolation capabilities.

Example

import brahe as bh

# Create from C04 file with interpolation
eop = bh.FileEOPProvider.from_c04_file(
    "./eop_data/finals2000A.all.csv",
    interpolate=True,
    extrapolate="Hold"
)

# Create from standard file
eop = bh.FileEOPProvider.from_standard_file(
    "./eop_data/finals.all",
    interpolate=True,
    extrapolate="Zero"
)

# Use default file location
eop = bh.FileEOPProvider.from_default_c04(True, "Hold")

# Set as global provider
bh.set_global_eop_provider_from_file_provider(eop)

# Get EOP data for a specific MJD
mjd = 60310.0
ut1_utc, pm_x, pm_y, dx, dy, lod = eop.get_eop(mjd)

Initialize instance.

eop_type `method descriptor` ¶

eop_type() -> str

Get the EOP data type.

Returns:

Name	Type	Description
`str`	`str`	EOP type string

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
print(f"EOP type: {eop.eop_type()}")

extrapolation `method descriptor` ¶

extrapolation() -> str

Get the extrapolation method.

Returns:

Name	Type	Description
`str`	`str`	Extrapolation method string

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
print(f"Extrapolation: {eop.extrapolation()}")

from_c04_file `builtin` ¶

from_c04_file(filepath: str, interpolate: bool, extrapolate: str) -> FileEOPProvider

Create provider from a C04 format EOP file.

Parameters:

Name	Type	Description	Default
`filepath`	`str`	Path to C04 EOP file	required
`interpolate`	`bool`	Enable interpolation between data points	required
`extrapolate`	`str`	Extrapolation method ("Hold", "Zero", or "Error")	required

Returns:

Name	Type	Description
`FileEOPProvider`	`FileEOPProvider`	Provider initialized with C04 file data

Example

import brahe as bh

eop = bh.FileEOPProvider.from_c04_file("./eop_data/finals2000A.all.csv", True, "Hold")
bh.set_global_eop_provider_from_file_provider(eop)

from_default_c04 `builtin` ¶

from_default_c04(interpolate: bool, extrapolate: str) -> FileEOPProvider

Create provider from the default C04 EOP file location.

Parameters:

Name	Type	Description	Default
`interpolate`	`bool`	Enable interpolation between data points	required
`extrapolate`	`str`	Extrapolation method ("Hold", "Zero", or "Error")	required

Returns:

Name	Type	Description
`FileEOPProvider`	`FileEOPProvider`	Provider initialized with default C04 file

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_c04(True, "Hold")
bh.set_global_eop_provider_from_file_provider(eop)

from_default_file `builtin` ¶

from_default_file(eop_type: str, interpolate: bool, extrapolate: str) -> FileEOPProvider

Create provider from default EOP file location with specified type.

Parameters:

Name	Type	Description	Default
`eop_type`	`str`	EOP file type ("C04" or "StandardBulletinA")	required
`interpolate`	`bool`	Enable interpolation between data points	required
`extrapolate`	`str`	Extrapolation method ("Hold", "Zero", or "Error")	required

Returns:

Name	Type	Description
`FileEOPProvider`	`FileEOPProvider`	Provider initialized with default file of specified type

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_file("C04", True, "Hold")
bh.set_global_eop_provider_from_file_provider(eop)

from_default_standard `builtin` ¶

from_default_standard(interpolate: bool, extrapolate: str) -> FileEOPProvider

Create provider from the default standard IERS EOP file location.

Parameters:

Name	Type	Description	Default
`interpolate`	`bool`	Enable interpolation between data points	required
`extrapolate`	`str`	Extrapolation method ("Hold", "Zero", or "Error")	required

Returns:

Name	Type	Description
`FileEOPProvider`	`FileEOPProvider`	Provider initialized with default standard file

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
bh.set_global_eop_provider_from_file_provider(eop)

from_file `builtin` ¶

from_file(filepath: str, interpolate: bool, extrapolate: str) -> FileEOPProvider

Create provider from an EOP file with automatic format detection.

Parameters:

Name	Type	Description	Default
`filepath`	`str`	Path to EOP file	required
`interpolate`	`bool`	Enable interpolation between data points	required
`extrapolate`	`str`	Extrapolation method ("Hold", "Zero", or "Error")	required

Returns:

Name	Type	Description
`FileEOPProvider`	`FileEOPProvider`	Provider initialized with file data

Example

import brahe as bh

eop = bh.FileEOPProvider.from_file("./eop_data/eop.txt", True, "Hold")
bh.set_global_eop_provider_from_file_provider(eop)

from_standard_file `builtin` ¶

from_standard_file(filepath: str, interpolate: bool, extrapolate: str) -> FileEOPProvider

Create provider from a standard IERS format EOP file.

Parameters:

Name	Type	Description	Default
`filepath`	`str`	Path to standard IERS EOP file	required
`interpolate`	`bool`	Enable interpolation between data points	required
`extrapolate`	`str`	Extrapolation method ("Hold", "Zero", or "Error")	required

Returns:

Name	Type	Description
`FileEOPProvider`	`FileEOPProvider`	Provider initialized with standard file data

Example

import brahe as bh

eop = bh.FileEOPProvider.from_standard_file("./eop_data/standard_eop.txt", True, "Hold")
bh.set_global_eop_provider_from_file_provider(eop)

get_dxdy `method descriptor` ¶

get_dxdy(mjd: float) -> tuple[float, float]

Get celestial pole offsets for a given MJD.

Parameters:

Name	Type	Description	Default
`mjd`	`float`	Modified Julian Date	required

Returns:

Type	Description
`tuple[float, float]`	tuple[float, float]: Celestial pole offsets dx and dy in radians

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
dx, dy = eop.get_dxdy(58849.0)
print(f"Celestial pole offsets: dx={dx} rad, dy={dy} rad")

get_eop `method descriptor` ¶

get_eop(mjd: float) -> tuple[float, float, float, float, float, float]

Get all EOP parameters for a given MJD.

Parameters:

Name	Type	Description	Default
`mjd`	`float`	Modified Julian Date	required

Returns:

Type	Description
`tuple[float, float, float, float, float, float]`	tuple[float, float, float, float, float, float]: UT1-UTC, pm_x, pm_y, dx, dy, lod

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
ut1_utc, pm_x, pm_y, dx, dy, lod = eop.get_eop(58849.0)
print(f"EOP: UT1-UTC={ut1_utc}s, PM=({pm_x},{pm_y})rad")

get_lod `method descriptor` ¶

get_lod(mjd: float) -> float

Get length of day offset for a given MJD.

Parameters:

Name	Type	Description	Default
`mjd`	`float`	Modified Julian Date	required

Returns:

Name	Type	Description
`float`	`float`	Length of day offset in seconds

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
lod = eop.get_lod(58849.0)
print(f"Length of day offset: {lod} seconds")

get_pm `method descriptor` ¶

get_pm(mjd: float) -> tuple[float, float]

Get polar motion components for a given MJD.

Parameters:

Name	Type	Description	Default
`mjd`	`float`	Modified Julian Date	required

Returns:

Type	Description
`tuple[float, float]`	tuple[float, float]: Polar motion x and y components in radians

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
pm_x, pm_y = eop.get_pm(58849.0)
print(f"Polar motion: x={pm_x} rad, y={pm_y} rad")

get_ut1_utc `method descriptor` ¶

get_ut1_utc(mjd: float) -> float

Get UT1-UTC time difference for a given MJD.

Parameters:

Name	Type	Description	Default
`mjd`	`float`	Modified Julian Date	required

Returns:

Name	Type	Description
`float`	`float`	UT1-UTC time difference in seconds

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
ut1_utc = eop.get_ut1_utc(58849.0)
print(f"UT1-UTC: {ut1_utc} seconds")

interpolation `method descriptor` ¶

interpolation() -> bool

Check if interpolation is enabled.

Returns:

Name	Type	Description
`bool`	`bool`	True if interpolation is enabled

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
print(f"interpolation: {eop.interpolation()}")

is_initialized `method descriptor` ¶

is_initialized() -> bool

Check if the provider is initialized.

Returns:

Name	Type	Description
`bool`	`bool`	True if initialized

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
print(f"is_initialized: {eop.is_initialized()}")

len `method descriptor` ¶

len() -> int

Get the number of EOP data points.

Returns:

Name	Type	Description
`int`	`int`	Number of EOP data points

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
print(f"EOP data points: {eop.len()}")

mjd_last_dxdy `method descriptor` ¶

mjd_last_dxdy() -> float

Get the last Modified Julian Date with dx/dy data.

Returns:

Name	Type	Description
`float`	`float`	Last MJD with dx/dy data

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
print(f"mjd_last_dxdy: {eop.mjd_last_dxdy()}")

mjd_last_lod `method descriptor` ¶

mjd_last_lod() -> float

Get the last Modified Julian Date with LOD data.

Returns:

Name	Type	Description
`float`	`float`	Last MJD with LOD data

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
print(f"Last MJD with LOD: {eop.mjd_last_lod()}")

mjd_max `method descriptor` ¶

mjd_max() -> float

Get the maximum Modified Julian Date in the dataset.

Returns:

Name	Type	Description
`float`	`float`	Maximum MJD

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
print(f"mjd_max: {eop.mjd_max()}")

mjd_min `method descriptor` ¶

mjd_min() -> float

Get the minimum Modified Julian Date in the dataset.

Returns:

Name	Type	Description
`float`	`float`	Minimum MJD

Example

import brahe as bh

eop = bh.FileEOPProvider.from_default_standard(True, "Hold")
print(f"Minimum MJD: {eop.mjd_min()}")

Overview¶

FileEOPProvider loads EOP data from files in either Standard or C04 format provided by the International Earth Rotation and Reference Systems Service (IERS).

Module: brahe.eop

Data Sources: - Standard Format: finals2000A.all - Combined rapid + predicted data - C04 Format: eopc04_IAU2000.XX - Long-term historical data

Creating a Provider¶

From Default Files¶

import brahe as bh

# Use default standard format file
provider = bh.FileEOPProvider.from_default_standard()

# Use default C04 format file
provider = bh.FileEOPProvider.from_default_c04()

From Custom Files¶

import brahe as bh

# Load from custom standard file
provider = bh.FileEOPProvider.from_standard_file(
    "/path/to/finals2000A.all",
    interpolate=True,
    extrapolate="Hold"
)

# Load from custom C04 file
provider = bh.FileEOPProvider.from_c04_file(
    "/path/to/eopc04.XX",
    interpolate=True,
    extrapolate="Hold"
)

Configuration Options¶

Interpolation¶

interpolate: bool - Enable/disable interpolation between data points

True: Linear interpolation for dates between data points (recommended)
False: Use nearest data point (step function)

Extrapolation¶

extrapolate: str - Behavior when querying dates outside data range

"Hold": Use first/last values for dates before/after data range
"Zero": Return zero for all EOP values outside range
"Error": Raise an error if date is outside range

Usage with Global EOP¶

import brahe as bh

# Create provider from file
provider = bh.FileEOPProvider.from_default_standard(
    interpolate=True,
    extrapolate="Hold"
)

# Set as global provider
bh.set_global_eop_provider(provider)

# Now all frame transformations use this EOP data
epoch = bh.Epoch.from_datetime(2024, 1, 1, 0, 0, 0.0, 0.0, bh.TimeSystem.UTC)
pos_eci = [7000000.0, 0.0, 0.0]
pos_ecef = bh.position_eci_to_ecef(epoch, pos_eci)

Downloading EOP Files¶

import brahe as bh

# Download latest standard EOP file
filepath = bh.download_standard_eop_file("./data")

# Download latest C04 EOP file
filepath = bh.download_c04_eop_file("./data")

# Use downloaded file
provider = bh.FileEOPProvider.from_standard_file(filepath)

FileEOPProvider¶