Table of Contents

Editor: RADAR Payloads

Description

The RADAR Payload allows users to simulate a mono-static RADAR type within Nominal Editor. The RADAR is capable of detecting any Unreal actor in the simulation as long as it has a mesh and has been added to the RADAR’s detectable objects array. Each RADAR Component has an Emitter Origin, which is used to define the reference position of where the RADAR measurements are made from. Having this separate from the origin of the component allows for additional customization.

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Parameter Configuration

The RADAR component has the following parameters that can be configured via the Details Panel:

  • Field of View: The Field of View of the RADAR in degrees
  • Range: The maximum effective distance of the RADAR in meters
  • Sample Rate: The time between RADAR samples in Seconds. Setting this parameter disables automatic RADAR sampling. Manual sampling is achieved by calling the Ping function to update the RADAR Sample Structure array.
  • Resolution: The number of sample points evenly distributed within the RADARs Field of View
  • Seed: The seed value to be used to generate noise for the Dynamic Error
  • Error Dynamic: A factor that represents the amount of dynamic noise added to distance values in the Samples array.
  • Error Constant: A consistent distance offset that is applied to the determined distance values
  • Trace to Targets: When the RADAR’s debug is enabled, this enables visible lines will be drawn from the RADAR emitter and the actors in the detectable objects array
  • Trace Ping: When the RADAR’s Debug is enabled, this enables visible lines to be drawn to the RADAR’s sample points that are based on its Field of View and Resolution
Note

The Field of View and Range cannot be adjusted mid-simulation. They must be defined either on the Begin Play event or in the associated Blueprint class.

Warning

As the RADAR Payload uses Unreal Ray Casts, consideration for simulation performance needs to be given when setting the Range and Resolution of the RADAR.

RADAR Output

The results generated by the RADAR Component are stored in a RADAR Sample Structure that contains:

  • Altitude: The Altitude angle of the sample in radians
  • Azimuth: The Azimuth angle of the sample in radians
  • Depth: The distance value of the sample in meters
  • Velocity: The velocity of the sample compared to the previous RADAR Ping in m/s
  • Hit Actor: The Unreal Actor detected by the sample, if one was detected
  • Noise Factor: The random Noise applied to this specific sample

The following functions can be used to access the sample structure data generated by the RADAR component:

  • Get Sample: Return a RADAR Sample Structure for a specified X and Y value. The X and Y values relate to the Resolution of the RADAR. To get all Samples using this function, place the function inside two nested For Loops (one for x, one for y) that iterate between 0 and one less than the RADAR’s resolution. An example of this is shown below.
  • Get Sample From Angle: For a configured Azimuth and Altitude, this function will return an instance of the RADAR Sample Structure
  • Get Visible Actors: Returns a list of every unique Actor that the RADAR detected on the previous Ping.

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RADAR Usage

Users have access to the following additional functions that are specific to the RADAR Component:

  • Load Targets: Triggers the RADAR to search for and add all acceptable Unreal Actors to the detectable objects array of the RADAR. The Add and Remove Actor To Targets functions can be used afterwards to augment the outcome. The following Actor types are automatically ignored:
    • Reaction Wheel Static Class
    • Spacecraft Static Class
    • Magnetic Torque Bar Static Class
    • This RADAR Component
    • The simulated Sun
    • Any Actor that is invalid or a null pointer
  • Add Actor To Targets: Adds a specific actor to the list of detectable objects for the RADAR.
  • Remove Actor From Targets: Removes a specific actor in the detectable objects array of the RADAR if it exists.
  • Remove All Targets: Removes every entry in the detectable objects array of the RADAR.
  • Set Resolution: Updates the Resolution of the RADAR and the backbend calculations dependant
  • Ping: Triggers the RADAR to update the RADAR Sample Structure array, applicable for when RADAR updates aren’t to be triggered by the Sample Rate (a negative Sample Rate disabled automatic RADAR Sample Structure updates).

The Load Targets function automatically includes the planets in the simulation and any Cesium tile sets, allowing for the RADAR to detect the height data of the planets for RADAR Imaging applications.

Warning

There is currently a disconnect between the mesh topology used for planets and their back-end models that may lead to inaccuracies in RADAR imaging applications.