StaticEOPProvider¶

Built-in Earth Orientation Parameters for testing and offline use.

StaticEOPProvider ¶

StaticEOPProvider()

Static Earth Orientation Parameter provider with constant values.

Provides EOP data using fixed values that don't change with time. Useful for testing or scenarios where time-varying EOP data is not needed.

Example

import brahe as bh

# Create static EOP provider with default values
eop = bh.StaticEOPProvider()

# Create static EOP provider with zero values
eop_zero = bh.StaticEOPProvider.from_zero()

# Create with custom values
eop_custom = bh.StaticEOPProvider.from_values(0.1, 0.0, 0.0, 0.0, 0.0, 0.0)

# Set as global provider
bh.set_global_eop_provider_from_static_provider(eop_custom)

Initialize instance.

doc `class-attribute` ¶

__doc__ = "Static Earth Orientation Parameter provider with constant values.\n\nProvides EOP data using fixed values that don't change with time.\nUseful for testing or scenarios where time-varying EOP data is not needed.\n\nExample:\n    ```python\n    import brahe as bh\n\n    # Create static EOP provider with default values\n    eop = bh.StaticEOPProvider()\n\n    # Create static EOP provider with zero values\n    eop_zero = bh.StaticEOPProvider.from_zero()\n\n    # Create with custom values\n    eop_custom = bh.StaticEOPProvider.from_values(0.1, 0.0, 0.0, 0.0, 0.0, 0.0)\n\n    # Set as global provider\n    bh.set_global_eop_provider_from_static_provider(eop_custom)\n    ```"

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

module `class-attribute` ¶

__module__ = 'brahe._brahe'

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

new `builtin` ¶

__new__(*args, **kwargs)

Create and return a new object. See help(type) for accurate signature.

repr `method descriptor` ¶

__repr__() -> str

Return repr(self).

str `method descriptor` ¶

__str__() -> str

Return str(self).

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.StaticEOPProvider.from_zero()
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.StaticEOPProvider.from_zero()
print(f"Extrapolation method: {eop.extrapolation()}")

from_values `builtin` ¶

from_values(ut1_utc: float, pm_x: float, pm_y: float, dx: float, dy: float, lod: float) -> StaticEOPProvider

Create a static EOP provider with specified values.

Parameters:

Name	Type	Description	Default
`ut1_utc`	`float`	UT1-UTC time difference in seconds	required
`pm_x`	`float`	Polar motion x-component in radians	required
`pm_y`	`float`	Polar motion y-component in radians	required
`dx`	`float`	Celestial pole offset dx in radians	required
`dy`	`float`	Celestial pole offset dy in radians	required
`lod`	`float`	Length of day offset in seconds	required

Returns:

Name	Type	Description
`StaticEOPProvider`	`StaticEOPProvider`	Provider with specified EOP values

Example

import brahe as bh

# Create EOP provider with custom values
eop = bh.StaticEOPProvider.from_values(
    ut1_utc=0.1,
    pm_x=1e-6,
    pm_y=2e-6,
    dx=1e-7,
    dy=1e-7,
    lod=0.001
)
bh.set_global_eop_provider_from_static_provider(eop)

from_zero `builtin` ¶

from_zero() -> StaticEOPProvider

Create a static EOP provider with all values set to zero.

Returns:

Name	Type	Description
`StaticEOPProvider`	`StaticEOPProvider`	Provider with all EOP values set to zero

Example

import brahe as bh

# Create EOP provider with all zeros (no corrections)
eop = bh.StaticEOPProvider.from_zero()
bh.set_global_eop_provider_from_static_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.StaticEOPProvider.from_zero()
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.StaticEOPProvider()
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.StaticEOPProvider.from_zero()
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.StaticEOPProvider.from_zero()
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.StaticEOPProvider.from_zero()
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.StaticEOPProvider.from_zero()
print(f"Interpolation enabled: {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.StaticEOPProvider.from_zero()
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.StaticEOPProvider.from_zero()
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.StaticEOPProvider.from_zero()
print(f"Last MJD with dx/dy: {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.StaticEOPProvider.from_zero()
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.StaticEOPProvider.from_zero()
print(f"Maximum MJD: {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.StaticEOPProvider.from_zero()
print(f"Minimum MJD: {eop.mjd_min()}")

Overview¶

StaticEOPProvider provides built-in historical EOP data that doesn't require external files. Useful for testing, examples, or when internet access is unavailable.

Module: brahe.eop

Use Cases: - Unit testing - Examples and tutorials - Offline applications - Quick prototyping

Limitations: - Fixed historical data (not updated) - Less accurate than file-based providers - Not suitable for production applications requiring current data

Creating a Provider¶

Zero Values¶

import brahe as bh

# All EOP values set to zero
provider = bh.StaticEOPProvider.from_zero()

# Set as global provider
bh.set_global_eop_provider(provider)

Custom Values¶

import brahe as bh

# Specify custom EOP values
provider = bh.StaticEOPProvider.from_values(
    ut1_utc=0.1,      # UT1-UTC offset (seconds)
    pm_x=0.0001,      # Polar motion X (radians)
    pm_y=0.0001,      # Polar motion Y (radians)
    dx=0.00001,       # Celestial pole offset dX (radians)
    dy=0.00001,       # Celestial pole offset dY (radians)
    lod=0.001         # Length of day offset (seconds)
)

Default Values¶

import brahe as bh

# Use built-in default values
provider = bh.StaticEOPProvider()

Usage Example¶

import brahe as bh

# Set up static EOP for testing
bh.set_global_eop_provider(
    bh.StaticEOPProvider.from_zero()
)

# Perform frame transformations
epoch = bh.Epoch.from_datetime(2024, 1, 1, 0, 0, 0.0, 0.0, bh.TimeSystem.UTC)

# ECI to ECEF transformation
pos_eci = [7000000.0, 0.0, 0.0]  # meters in ECI
pos_ecef = bh.position_eci_to_ecef(epoch, pos_eci)

# ECEF to ECI transformation
vel_ecef = [0.0, 7500.0, 0.0]  # m/s in ECEF
vel_eci = bh.position_ecef_to_eci(epoch, vel_ecef)

When to Use¶

✅ Use StaticEOPProvider for: - Unit tests - Documentation examples - Learning and prototyping - Applications where high accuracy isn't critical

❌ Don't use StaticEOPProvider for: - Production orbit determination - Precise tracking applications - Applications requiring current EOP data - High-accuracy simulations

StaticEOPProvider¶