Eclipse Shadow Model (Dual Cone)

Calculate fraction of solar disk visible at inertial positions

Since R2023b

• 

Libraries:
Aerospace Blockset / Environment / Celestial Phenomena

Alternative Configurations of Eclipse Shadow Model (Dual Cone) Block:
Eclipse Shadow Model (Cylindrical)

Description

The Eclipse Shadow Model (Dual Cone) block calculates the fraction of the solar disk that is visible from the provided inertial positions, assuming that the occulted bodies and the Sun are spherical. The block operates with two shadow models:

Dual cone model — The block differentiates between partial, annular, and total eclipse, which means the spacecraft can be in sunlight, penumbra, antumbra, or umbra. The eclipse is partial in penumbra, annular in antumbra, and total in umbra. In summary:

• Umbra, no sunlight — 0

• Penumbra or Antumbra, partial sunlight — 0 to 1

• Full sunlight — 1

Cylindrical model — The block differentiates only between total eclipse (umbra) and full sunlight. For more information, see Alternative Configurations section.

• Umbra, no sunlight — 0

• Full sunlight — 1

Ports

Input

X_icrf — Position of spacecraft

3-element vector | M-by-3 array

Position of the spacecraft with respect to ICRF coordinate system, specified as a 3-element vector or M-by-3 array, where M is the number of spacecraft. The Units parameter controls the units designation.

Data Types: double

T_JD — Julian date

scalar

Julian date specified as a scalar.

Dependencies

To enable this port, set Dialog to Port (Julian date).

Data Types: double

T0_JD — Julian date epoch

scalar

Julian date epoch from which to base elapsed Julian time, specified as a scalar.

Dependencies

To enable this port, set Dialog to Port (T0 and elapsed Julian time).

Data Types: double

ΔT_JD — Elapsed Julian time with respect to T0_JD

scalar

Elapsed Julian time with respect to ΔT_JD, specified as a scalar elapsed time.

Dependencies

To enable this port, set Dialog to Port (Julian date).

Data Types: double

R_ssbary,_cb — Custom central body position

3-by-1 array

Custom central body position with respect to the solar system barycenter, in the ICRF coordinate frame.

Dependencies

To enable this port, set Central body to Custom.

Data Types: double

Output

Fraction — Fraction of visible Sun

scalar | M-element vector

Fraction of visible Sun (eclipse), returned as a scalar or vector of size M. M is the number of input spacecraft.

Dependencies

• When the Shadow model parameter is set to Dual cone, the values are 0 (Umbra), between 0 and 1 (Penumbra or Antumbra), or 1 (Sunlight).

• When the Shadow model parameter is set to Cylindrical, the values are 0 (Umbra) or 1 (Sunlight).

Data Types: double

Region — Region

scalar | M-element vector | integer

Region depending on Shadow model value, returned as a scalar or M-element vector of integers. M is the number of spacecraft.

• When the Shadow model parameter is set to Dual cone, region can be 0 (Umbra), between 0 and 1 (Penumbra or Antumbra), or 1 (Sunlight).

• When the Shadow model parameter is set to Cylindrical, region can be 0 (Umbra) or 1 (Sunlight).

Dependencies

To enable this port:

• Select the Output index of shadow region check box.

Data Types: int32

Secondary Region — Secondary region

scalar | M-element vector | integer

Region depending on Shadow model value, returned as a scalar or M-element vector of integers. M is the number of spacecraft.

• When the Shadow model parameter is set to Dual cone, region can be 0 (Umbra), between 0 and 1 (Penumbra or Antumbra), or 1 (Sunlight).

• When the Shadow model parameter is set to Cylindrical, region can be 0 (Umbra) or 1 (Sunlight).

Dependencies

To enable this port, select the Output index of shadow region check box and one of these settings:

• • Set Central body to Earth.

  • Select Include Moon.

or:

• • Set Central body to Moon.

  • Select Include Earth.

Data Types: int32

Parameters

Units — Position port units

Metric (m) (default) | Metric (km) | English (ft) | English (M)

Position port units, specified as one of these values:

Units	Distance
Metric (m)	meters
Metric (km)	kilometers
English (ft)	feet
English (M)	miles

Programmatic Use

Block Parameter: units

Type: character vector

Values: 'Metric (m)' | 'Metric (km)' | 'English (ft)' | 'English (M)'

Default: 'Metric (m)'

Shadow model — Shadow model

Dual cone (default) | Cylindrical

Shadow model for eclipse calculations, specified as one of these values.

• Cylindrical — Fraction can be 0.0 (Umbra) or 1.0 (Sunlight).

• Dual cone — Fraction can be 0.0 (Umbra), between 0.0 and 1.0 (Penumbra or Antumbra), or 1.0 (Sunlight).

Programmatic Use

Block Parameter: shadowModel

Type: character vector

Values: 'Dual cone' | 'Cylindrical'

Default: 'Dual cone'

Output index of shadow region — Output index of shadow region

on (default) | off

To enable the port for the index of the shadow region, select this check box. Otherwise, clear this check box.

Programmatic Use

Block Parameter: outputShadowRegion

Type: character vector

Values: 'off' | 'on'

Default: 'on'

Time source — Time source method

Dialog (default) | Port (Julian date) | Port (T0 and elapsed Julian time)

Time source method, specified as one of these values:

• Dialog — Block dialog parameter.

• Port (Julian date) — T_JD port.

• Port (T0 and elapsed Julian time) — T_JD and ΔT_JD ports.

Programmatic Use

Block Parameter: timeSource

Type: character vector

Values:'Dialog' | 'Port (Julian date)' | 'Port (T0 and elapsed Julian time)'

Default: 'Dialog'

Start date/time (JD) — Initial start date and time for simulation

juliandate(2020, 1, 1) (default) | valid scalar Julian date

Initial start date and time of simulation, specified as a valid scalar Julian date. To determine the current time at each simulation timestep, the block adds elapsed simulation time to this value.

Tip

To calculate the Julian date, use the juliandate function.

Dependencies

To enable this parameter, set Time source to Dialog.

Programmatic Use

Block Parameter: startDate

Type: character vector

Values:'juliandate(2020, 1, 1)' | valid scalar Julian date

Default: 'juliandate(2020, 1, 1)'

Central body — Occulting celestial body for eclipse calculations

Earth (default) | Moon | Mercury | Venus | Mars | Jupiter | Saturn | Uranus | Neptune | Custom

Occulting celestial body for eclipse calculations, specified as Earth, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, or Custom.

Position inputs are referenced with respect to the origin of the central body.

Programmatic Use

Block Parameter: centralBody

Type: character vector

Values: 'Earth' | 'Moon' |'Mercury' | 'Venus' | 'Mars' | 'Jupiter' | 'Saturn' | 'Uranus' | 'Neptune' | 'Custom' |

Default: 'Earth'

Custom radius — Custom central body radius

3396200 (default) | double scalar

Equatorial radius for a custom central body, specified as a double scalar in the units specified in the Units parameter..

Dependencies

To enable this parameter, set Central body to Custom.

Programmatic Use

Block Parameter: customR

Type: character vector

Values: '3396200' | double scalar

Default: '3396200'

Include Moon — Option to include Moon

on (default) | off

Option to include Moon as a secondary occulting body in eclipse calculations when central body is Earth.

Dependencies

Set the Central body parameter to Earth.

Programmatic Use

Block Parameter: includeMoon

Type: character vector

Values: 'off' | 'on'

Default: 'on'

Include Earth — Option to include Earth

on (default) | off

Option to include Earth as a secondary occulting body in eclipse calculations when central body is Moon.

Dependencies

Set the Central body parameter to Moon.

Programmatic Use

Block Parameter: includeEarth

Type: character vector

Values: 'off' | 'on'

Default: 'on'

Ephemeris model — Ephemeris model

DE405 (default) | DE421 | DE423 | DE430 | DE432t

Select one of these ephemerides models defined by the Jet Propulsion Laboratory.

Ephemeris Model	Description
DE405	Released in 1998. This ephemeris takes into account the Julian date range 2305424.50 (December 9, 1599) to 2525008.50 (February 20, 2201). This block implements these ephemerides with respect to the International Celestial Reference Frame version 1.0, adopted in 1998.
DE421	Released in 2008. This ephemeris takes into account the Julian date range 2414992.5 (December 4, 1899) to 2469808.5 (January 2, 2050). This block implements these ephemerides with respect to the International Celestial Reference Frame version 1.0, adopted in 1998.
DE423	Released in 2010. This ephemeris takes into account the Julian date range 2378480.5 (December 16, 1799) to 2524624.5 (February 1, 2200). This block implements these ephemerides with respect to the International Celestial Reference Frame version 2.0, adopted in 2010.
DE430	Released in 2013. This ephemeris takes into account the Julian date range 2287184.5 (December 21, 1549) to 2688976.5 (January 25, 2650). This block implements these ephemerides with respect to the International Celestial Reference Frame version 2.0, adopted in 2010.
DE432t	Released in April 2014. This ephemeris takes into account the Julian date range 2287184.5, (December 21, 1549 ) to 2688976.5, (January 25, 2650). This block implements these ephemerides with respect to the International Celestial Reference Frame version 2.0, adopted in 2010.

Note

This block requires that you download ephemeris data using the Add-On Explorer. To start the Add-On Explorer, in the MATLAB^® Command Window, type aeroDataPackage. In the MATLAB desktop toolstrip, click Add-Ons.

Programmatic Use

Block Parameter: ephemerisModel

Type: character vector

Values: DE405 | DE421 | DE423 | DE430

Default: 'DE405'

Limit ephemerides date range — Open to enable start and end of range of ephemeris data

on (default) | off

Control how much data is loaded into memory during simulation and how much data is included in generated code for the block:

• Clear this check box to include data for the complete date range defined in the Ephemeris model table.

• Select this check box to limit the loading of ephemeris data to a specified date range.

Programmatic Use

Block Parameter: useDateRange

Type: character vector

Values: 'off' | 'on' |

Default: 'on'

Start date (JD) — Start date of ephemerides date range

juliandate(2020, 1, 1) (default) | Julian date

Start date of ephemerides date range, specified as a Julian date.

Dependencies

To enable this parameter, select the Limit ephemerides date range check box.

Dependencies

To enable this parameter:

• Set the Propagation method parameter to Numerical (high precision).

• Set the Limit ephemerides date range parameter to on.

Programmatic Use

Block Parameter: startDate

Type: character vector

Values: 'juliandate(2020, 1, 1)' | Julian date

Default: 'juliandate(2020, 1, 1)'

End date (JD) — End date of ephemerides date range

juliandate(2050, 1, 1) (default) | Julian date

End date of ephemerides date range, specified as a Julian date.

Dependencies

To enable this parameter, select the Limit ephemerides date range check box.

Dependencies

To enable this parameter:

• Set the Propagation method parameter to Numerical (high precision).

• Set the Limit ephemerides date range parameter to on.

Programmatic Use

Block Parameter: endDate

Type: character vector

Values: 'juliandate(2050, 1, 1)' | Julian format date

Default: 'juliandate(2050, 1, 1)'

Action for out-of-range input — Out-of-range block behavior

Error (default) | Warning | None

Out-of-range block behavior, specified as one of these values:

Action	Description
None	No action.
Warning	Warning in the Diagnostic Viewer, model simulation continues.
Error (default)	Error in the Diagnostic Viewer, model simulation stops.

Programmatic Use

Block Parameter: action

Type: character vector

Values: 'None' | 'Warning' | 'Error'

Default: 'Error'

Alternative Configurations

Eclipse Shadow Model (Cylindrical) — Calculate fraction of solar disk visible at inertial positions

The Eclipse Shadow Model (Cylindrical) block calculates a fraction of the solar disk visible at inertial positions while assuming that:

• The Sun is infinitely far from the occulting bodies and the spacecraft.

• All rays of sunlight are parallel.

The block cannot differentiate between partial, annular, and total eclipse, which means the that the eclipse is either full sunlight or umbra only.

Differences between this block and the Eclipse Shadow Model (Cylindrical) include:

• Shadow model is Cylindrical by default.

• Output index of shadow region is cleared by default, resulting in only the output Fraction port appearing by default.

Libraries:
Aerospace Blockset / Environment / Celestial Phenomena

Extended Capabilities

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

Version History

Introduced in R2023b