pointAt

R2026b

Point transmitter or receiver at target

Since R2023a

Syntax

pointAt

pointAt(asset,"none")

pointAt(asset,coordinates)

pointAt(asset,target)

pointAt(asset,"nadir")

pointAt(asset,weights)

pointAt(___,ReferenceCelestialBody=celestialBody)

Description

pointAt specifies the target at which the phased array antenna on a transmitter or a receiver must point. The antenna is electronically steered toward the desired target by computing the appropriate weights and assigning them to the array elements. The antenna is continuously steered electronically for the duration of the simulation to point at the desired target.

Note

For satellites and gimbals, use this pointAt function.

pointAt(asset,"none") disables pointing for the transmitters or receivers specified by asset. All elements in asset must contain a phased array antenna. The phased array weights are set to the original values as they were at the time of creation of the transmitter or receiver. "none" is the default pointing mode.

pointAt(asset,coordinates) steers the phased array antennas in transmitters or receivers in the vector asset toward the planetographic coordinates specified by coordinates. The coordinates are referenced to the central body of the parent, unless a ReferenceCelestialBody name-value argument is specified. If the parent is a matlabshared.satellitescenario.Satellite, matlabshared.satellitescenario.GroundStation, or matlabshared.satellitescenario.Platform object, the central body is specified by the CentralBody property of the object. If the parent is a matlabshared.satellitescenario.Gimbal object, the central body is specified by the CentralBody property of the parent of the gimbal, which in turn can be a matlabshared.satellitescenario.Satellite, matlabshared.satellitescenario.GroundStation, or matlabshared.satellitescenario.Platform object.

pointAt(asset,target) steers phased array antennas in transmitters or receivers specified by asset toward the specified target target. Input target can be a satellite, ground station, or platform, specified as a scalar or a vector.

pointAt(asset,"nadir") steers the phased array antennas in transmitters or receivers specified by the row vector asset toward the nadir direction of their respective parents, specified by latitude and longitude of the parent, and 0 m altitude. The latitude and longitude are defined on central body of the parent, unless a ReferenceCelestialBody name-value argument is specified.

pointAt(asset,weights) explicitly assigns the weights for the phased array antenna elements of the transmitters or receivers.

pointAt(___,ReferenceCelestialBody=celestialBody) specifies the celestial body used to define the nadir direction or the celestial body with respect to which coordinates is defined.

Input Arguments

asset — Transmitter or receivers

scalar | vector

Transmitter or receiver objects, specified as either a scalar or a vector.

coordinates — Planetographic coordinates of transmitter or receiver

three-element vector | 2-D array

Planetographic coordinates of the transmitter or receiver, specified as a three-element vector, or a two-dimensional array.

• When specified as a three-element vector, the elements correspond to the latitude, longitude, and altitude, in that order, and all assets are steered to point at this location.

• When coordinates is specified as an array, the number of rows must equal three. The number of columns must equal the number of assets in asset. The rows correspond to the latitude, longitude, and altitude, in that order, and each column represents the pointing coordinates of the corresponding asset in the vector asset. The latitudes and longitudes are specified in degrees and the altitudes are specified in meters. They represent the height above the surface of the central body of the parent, unless a ReferenceCelestialBody name-value argument is specified.

target — Target

scalar | vector

Target at which input asset is pointed. Input target can be a satellite, ground station, or platform, specified as a scalar or a vector.

• When specified as a scalar, all assets point to the specified target.

• If target is a vector, its length must equal the number of assets in asset, and each element in target represents the pointing target of an asset in asset.

weights — Weights for phased array antenna elements

scalar | vector

Weights for phased array antenna elements, specified as a scalar or a vector of complex numbers whose length is equal to the number of phased array elements.

ReferenceCelestialBody — Reference celestial body for pointing

CentralBody property of parent (default) | "Earth" | "Moon"

Since R2026b

Reference celestial body used to:

• Define the "nadir" direction.

• Define the celestial body with respect to which coordinates is defined.

The valid values are "Earth" and "Moon". If you specify "Moon" and the Moon has not been added to the satellite scenario, the function returns an error. To add the Moon, use the centralBodyOptions (Aerospace Toolbox) function.

ReferenceCelestialBody is ignored when all of these conditions are true:

• coordinates input is not used.

• "nadir" input is not used.

The default value is the celestial body defined by the CentralBody property of the parent matlabshared.satellitescenario.Satellite, matlabshared.satellitescenario.GroundStation, or matlabshared.satellitescenario.Platform object.

Data Types: string

Version History

Introduced in R2023a

R2026b: Support for pointing at lunar targets

You can now point transmitter and receiver phased array antennas at lunar assets (satellites, ground stations, and platforms with CentralBody="Moon"), at Moon nadir, and at Moon surface coordinates. When pointing at a lunar target, the secondary constraint vector is locked to the ICRF velocity with respect to the pointed‑at body.