EarthCenteredKeplerian

R2026b

Target specification for earth-centered Keplerian satellite

Since R2026b

Description

An EarthCenteredKeplerian object contains a target specification for an earth-centered satellite in a Keplerian orbit. You can use the EarthCenteredKeplerian object as an input target specification to multiSensorTargetTracker. The target specification defines the state convention for trackers initialized with it. For EarthCenteredKeplerian, the output state convention is [x;vx;y;vy;z;vz] in the Earth-centered inertial (ECI) coordinate frame, where:

• x, y, and z represent the x-, y-, and z-coordinates in meters.

• vx, vy, and vz represent the velocity components in different directions in meters per second.

The state transition model uses a Keplerian satellite motion model with disturbance acceleration noise.

Note

The EarthCenteredKeplerian target specification requires an Aerospace Toolbox license.

Creation

To create an EarthCenteredKeplerian object, use the trackerTargetSpec function with the input arguments "space", "earth-centered", and "keplerian". For example:

spec = trackerTargetSpec("space","earth-centered","keplerian")

Properties

MinAltitude — Minimum altitude of target above Earth surface

120000 (default) | nonnegative scalar

Minimum altitude of the target above the Earth surface, specified as a nonnegative scalar. Tracks are deleted rapidly when their altitude falls below this value. The value must be less than MaxAltitude. Units are in meters. The altitude is computed using an assumed Earth radius of 6356752.3 meters.

Example: 100000

Data Types: single | double

MaxAltitude — Maximum altitude of target above Earth surface

2000000 (default) | positive scalar

Maximum altitude of the target above the Earth surface, specified as a positive scalar. Tracks are deleted rapidly when their altitude exceeds this value. The value must be greater than MinAltitude. Units are in meters. The altitude is computed using an assumed Earth radius of 6356752.3 meters.

Example: 1500000

Data Types: single | double

MaxSpeed — Maximum speed of target

8000 (default) | positive scalar

Maximum speed of the target, specified as a positive scalar. This value characterizes the velocity standard deviation used for track initialization. Units are in meters per second.

Example: 7800

Data Types: single | double

MaxDisturbanceAcceleration — Maximum disturbance acceleration of target

0.02 (default) | nonnegative scalar

Maximum disturbance acceleration of the target, specified as a nonnegative scalar. This value characterizes the process noise intensity in the Keplerian satellite motion model and accounts for perturbations such as atmospheric drag, solar radiation pressure, and gravitational harmonics. Units are in meters per second squared.

Example: 0.01

Data Types: single | double

Object Functions

hasTrackerInput

Determine whether tracker needs additional input for target specification

Examples

Create and Configure Specification for Earth-Centered Keplerian Satellite

Create an earth-centered Keplerian satellite target specification.

spec = trackerTargetSpec("space","earth-centered","keplerian")

spec = 
  EarthCenteredKeplerian with properties:

                   MinAltitude: 1.2e+05    m   
                   MaxAltitude: 2e+06      m   
                      MaxSpeed: 8000       m/s 
    MaxDisturbanceAcceleration: 0.02       m/s²

Configure the satellite specification based on your application. The satellite of interest have a maximum speed of 7.5 km/s.

spec.MaxSpeed = 7500;

More About

Keplerian Satellite Motion Model

The EarthCenteredKeplerian target specification uses a Keplerian satellite motion model for state transition. The model propagates satellite states in the Earth-centered inertial (ECI) coordinate frame using two-body orbital mechanics, where the primary gravitational force is from the Earth.

The model accounts for small perturbations, such as atmospheric drag, solar radiation pressure, and gravitational harmonics, through a disturbance acceleration noise term. The MaxDisturbanceAcceleration property controls the intensity of this noise.

Tracks with altitudes within the range defined by MinAltitude and MaxAltitude have a high probability of survival during prediction. Tracks with altitudes outside this range are deleted rapidly.

Tips

• To deploy an application that uses satellite specifications using MATLAB^® Compiler™, add propagateOrbit as a dependency to the deployed application package. To do this, you can either use the -a filepath (MATLAB Compiler) input argument of the mcc (MATLAB Compiler) function or use the %#function (MATLAB Compiler) pragma in your entry-point function.

Version History

Introduced in R2026b