Movers and Routes

A mover is a platform subsystem that defines how a platform is able to move within its environment. A route is an ordered list of specific positions (or waypoints) that define the path of a particular platform as it moves.

Several domain specific AFSIM mover types include:

WSF_AIR_MOVER

WSF_GROUND_MOVER

WSF_SURFACE_MOVER

WSF_ROAD_MOVER

Quick Start

A mover may be defined within a platform definition, within a platform type definition, or defined independently, and added to or modified within a given platform or platform type.

The following code samples result in the same output and are scalable. To encourage best practices and use of abstraction, a platform defined mover is not provided:

Independently Defined Mover	Platform Type Defined Mover
mover CARGO_AIR_MOVER WSF_AIR_MOVER operational update_interval 3 sec end_mover platform_type CARGO_AIRCRAFT WSF_PLATFORM icon c130 spatial_domain air category cargo add mover CARGO_AIR_MOVER end_mover end_platform_type	platform_type CARGO_AIRCRAFT WSF_PLATFORM icon c130 spatial_domain air category cargo mover WSF_AIR_MOVER operational update_interval 3 sec end_mover end_platform_type

The following code sample demonstrates the basics of a platform route. Add a route to a platform by including the following route command block in the platform definition:

route
   position 00:30s 01:30w altitude 8000 m speed 500 km/h
   position 00:30s 01:45e
end_route

The platform’s initial position will be set to the first position defined in the route. Subsequent position commands will define subsequent locations in the route. Labels may be used to create loops in a route if desired. If not specified, the default route altitude is determined from the owning platform’s initial position information, if available. The altitude and speed arguments are optional for a given position. If not specified, a platform will remain at the last specified altitude and speed.

Closer Look

Movers are the first in a list of several platform parts which are critical to AFSIM simulations. Though the two are not synonymous, for simpler platforms such as ground vehicles, it is often helpful to think of a mover as a vehicles engine. However, this analogy breaks down for multi-engine vehicles such as aircraft, which in most cases require only a single mover.

Note

The following steps assume that the “simple_flight” scenario is present as discussed in Platforms and Platform Types.

Adding Movers to a Scenario

1. Open the simple_flight project and simple_flight.txt in Wizard.

2. Add the following mover command block within the CARGO_AIRCRAFT platform type definition and save the file:

   mover WSF_AIR_MOVER
      operational
   end_mover
   

   Note

   With the addition of this mover block, any platforms inheriting from the CARGO_AIRCRAFT platform type are capable of powered flight through (Earth) air.

3. Now capable of powered flight, platforms inheriting the CARGO_AIRCRAFT platform type require initial kinematic state information. This should be provided as part of a route.

Adding Platform Routes

1. Add the following route command block to platform “cargo-1”:

   route
      position 00:30s 01:30w altitude 8000 m speed 500 km/h
      position 00:30s 01:30e
   end_route
   

2. In the Wizard Map Display, select “cargo-2”.

3. Right click cargo-2 to open the context menu. From there, select Route, then select Create Route on cargo-2. This will create a waypoint at the platform and a route in the platform’s definition in the scenario file.

4. With cargo-2’s first route waypoint selected, right click the map display somewhere near coordinate 00:30s 01:45w (just west of cargo-1’s initial position) and select Add at Location, Waypoint after selection.

5. Though the formatting may vary, this process will result in cargo-2’s route resembling the following:

   route
      position 00:30s 01:30e altitude 8000 m speed 500 km/h
      position 00:30s 01:45w
   end_route
   

6. Save the file.

Wizard’s Map Display should reflect the following:

Note that with the routes provided, “cargo-1” and “cargo-2” are on a collision course, having only minutes to react before colliding. The focus of upcoming modules is to provide these aircraft the means to avoid a collision, and return to their assigned routes after navigating around one another.

Review

After completing this section, the simple_flight project should include a single scenario file, simple_flight.txt that reflects the following:

# simple_flight demo

simulation_name "Simple Flight"

execute at_time 0.1 sec absolute
   writeln("\nSimulating simple_flight scenario...");
end_execute

end_time 30 min

platform_type CARGO_AIRCRAFT WSF_PLATFORM
   icon c130
   spatial_domain air
   category cargo

   mover WSF_AIR_MOVER
      update_interval 3 sec
   end_mover

end_platform_type

platform cargo-1 CARGO_AIRCRAFT
   heading 90 deg
   altitude 8000m

   route
      position 00:30s 01:30w altitude 8000 m speed 500 km/h
      position 00:30s 01:45e
   end_route

end_platform

platform cargo-2 CARGO_AIRCRAFT
   heading -90 deg
   altitude 8000m

   route
      position 00:30s 01:30e altitude 0.00 ft speed 500 kmh
      position 00:30s 01:45w
   end_route

end_platform

Summary

Movers facilitate movement of the owning platform, and routes provide travel instructions to platforms. Routes may be created with the Wizard Map Display, or directly from within a given scenario file. In either case, existing routes may be modified via both interfaces as well. A platform’s route will override the existing initial position and kinematic state of the owning platform if they are defined, so it is unnecessary to provide an initial position to a platform if an initial route is provided.

For more advanced simulations, multiple movers may exist on a single platform, facilitating the simulation of cross-domain vehicles, such as an aircraft capable of landing and moving on water.

Routes may also include labels to allow a platform to repeat a route indefinitely.

Related Topics

Wizard

Platforms and Platform Types

Sensors and Signatures