The Satellite Object

The Satellite object models the properties and behavior of a vehicle in orbit around a central body. Select one or more of the following to model a satellite, impose constraints, and define the satellite's subobjects:

Basic Properties

Property Description
Orbit

Define a satellite's orbit, including coordinate system, orbital elements and time parameters for the following propagators:

Two Body J2 Perturbation J4 Perturbation HPOP
SGP4 GPS LOP StkExternal
SPICE Astrogator Real-time  
Attitude Define an attitude profile for the satellite.
Pass Break Specify the event that defines the boundary between passes (or revolutions) of an orbiting satellite.
Mass Specify the satellite's moment of inertia tensor and its mass.
Eclipse Bodies Define the eclipse central body list used for lighting computations.
Reference Specify a vehicle to be used as a reference satellite in a formation flying situation.
Ground Ellipses Add a set of ellipses for the satellite.
EOIR Shape Specify EOIR image generation properties for the satellite.
SEET

SEET property pages allow values to be entered that affect calculations involving the space environment as modeled by the STK/SEET Space Environmental Effects Tool:

  • Environment. Set parameters that affect the magnetic field model, and the entrance and exit times and probable fluxes due to a vehicle crossing the South Atlantic Anomaly (SAA), a region of space with an enhanced concentration of ionizing radiation.
  • Thermal. Set material properties and average Earth albedo that affect the determination of vehicle temperature exposed to direct solar and reflected Earth radiation.
  • Particle Flux. Set parameters that affect the determination of the level of (damaging) exposure due to meteroids and debris particles.
  • Radiation. Set parameters that affect the expected ionizing dose rate and energetic particle fluxes due to the trapped electron and proton populations, as well as integrated total dose and fluence (flux integrated over time).

STK/SEET radiation computations are also affected by scenario-level settings.
Description Record useful information about the satellite.

2D Graphics Properties

Property Description
Attributes Define color, line style and other graphics characteristics for the satellite, and opt whether to inherit or override global attributes defined at the Scenario level.
Time Events Display text, a marker, or a line to indicate an event that occurs at a particular time on the satellite's ground track
Pass Control the display of a satellite's ground track and orbit path in the 2D Graphics window.
Contours Define elevation angle contours in the 2D Graphics window.
Range Define range contours representing the various regions of the surface that can see an object at the specified level.
Lighting Define the graphical display of lighting conditions for the satellite during animation.
Swath Calculate and graphically display swath for the satellite.
Ground Ellipses Set the display graphics for a ellipse set defined on the Basic Ground Ellipse page for vehicles.
SEET Environment

Set parameters that affect the display of the magnetic field and the contours of the South Atlantic Anomaly (SAA) in relation to the vehicle, as modeled by the STK/SEET Space Environmental Effects Tool.

3D Graphics Properties

Property Description
Pass Control the display of the satellite's ground track and orbit path in the 3D Graphics window.
Orbit System Show the satellite’s orbit in a variety of coordinate systems.
Attitude Sphere The Attitude Sphere is a visualization aid that when combined with vector display constitutes a powerful tool for displaying the object's attitude and for tracking attitude changes over time.
Vector Control the display of vectors and other geometric elements related to the satellite.
Proximity Control the position of the satellite in the 3D Graphics window.
Drop Lines Define the display of lines between the satellite's orbit (the actual path that the satellite follows) and the central body.
Covariance Define the graphical display of a 3D ellipsoid.
B-Plane Control the display of B-Planes for the satellite.
Model Specify a model to represent the satellite in the 3D Graphics window, and then scale the model and adjust the position of any model articulations.
Offsets Position a model and marker representing the satellite in the 3D Graphics window by offsetting the object from its reference frame.
Contours Define elevation angle contours in the 3D Graphics window.
Range Display range contours for the satellite. Range contours display in accordance with the values set for the 2D Graphics Range Contours for the satellite.
Model Pointing Point parts of the satellite model toward a target, such as the Sun or Earth.
Data Display Display dynamic data for the satellite in the 3D Graphics window.
Vapor Trail Add a vapor trail to the satellite.

Constraints

Property Description
Basic Impose a variety of standard access constraints (azimuth and elevation angle and rate, range and range rate, propagation delay, etc.) from the satellite to another object.
Sun Impose a variety of access constraints from the satellite to another object based on the position of the Sun and the Moon.
Temporal Impose time-based access constraints from the satellite to another object.
Advanced Impose several advanced access constraints (grazing angle and altitude, doppler cone angle, solar beta angle, etc.) from the satellite to another object.
Zones Use inclusion and exclusion zones to define areas where access is or is not allowed.
Targeting Define the relationship between the satellite and its target in terms of cross-track range, in-track range and squint angle.
Vector Constrain access computations with respect to any valid vector or angle.
Special Special access constraints are defined in terms of geostationary belt exclusion, height above horizon, terrain grazing angle and exclusion of other scenario objects.
Search/Track

Radar Search/Track Constraints property pages allow minimum and maximum values to be entered for several parameters and presents a variety of doppler options:

  • Search/Track. These parameters correspond to the radar's main channel. These parameters account for the polarization mismatch, if polarization is selected on the Basic Polarization page.
  • ST w/Jamming. These parameters correspond to the main channel radar receiver that is under the influence of jamming. When the radar receiver polarization is set and the jammers are polarized, the search/track parameters take polarization mismatch into account. Most of these parameters are re-computed under the impact of jamming on the radar receiver main channel. For more information on the effects of jamming on constraints, see Constraints with Jamming.
  • S/T OrthoPol. These parameters correspond to the radar's orthogonal polarization channel.
  • S/T OrthoPolJam. These parameters correspond to the radar's orthogonal polarization channel under the threat of jamming.

The STK/Radar SAR computation and constraints can be extended with the Search/Track plug-in constraint. See Search Track User Plugin.
SAR

SAR property pages allow for the imposition of a variety of constraints on synthetic aperture (SAR) radar.

  • SAR. These parameters correspond to the main channel (SAR).
  • SAR w/Jamming. These parameters correspond to the main channel under jamming. For more information on the effects of jamming on constraints, see Constraints with Jamming.
  • SAR OrthoPol. These parameters are enabled when the receiver side orthogonal polarization is selected.
  • SAR OrthoPolJam. These parameters are enabled when the receiver side orthogonal polarization is selected. For more information on the effects of jamming on constraints, see Constraints with Jamming.

The STK/Radar SAR computation and constraints can be extended with the Search/Track plug-in constraint. See SAR User Plugin.
Plugins An interface is provided for defining custom constraints in terms of user-supplied scripts created in Perl, VBScript and MATLAB.
SEET Special access constraints are imposed based on relationships of the vehicle with, and the effects of, the space environment as modeled by the STK/SEET Space Environmental Effects Tool (e.g., debris and meteroid fluxes, radiation fluxes, vehicle temperature, magnetic field, etc.).

Satellite Subobjects

You can attach the following subobjects to a satellite: