MAVS Simulation Input Files

MAVS primarily uses json input files. These files describe everything from the scene geometry to the simulation time step. This page documents the simulation input files and their contents.

There are two primary input file types: Input to autonomy simulations and input to sensor simulations. Some of the input fields in these files are paths to other json files, which will be discussed below.

Autonomy Simulation Inputs

An autonomy simulation contains a single vehicle with one or more attached sensors operating in a digital terrain.

Scene

"Scene":{
		 "Input File":"/media/sf_vm_shared/mavs/data/scenes/grass_maze.json",
		 "Origin": [32.3526,90.8779,73.152],
		  "Time Zone":6
	}

• “Input File”: Full path to the json input file defining the scene geometry. See the “Scene Input File” section below for details.
• “Origin”: The latitude, longitude, and altitude of the origin of the scene ([0,0,0] in East-North-Up coordinates) in decimal degrees and meters. Postive = Northing / Westing. For more information, see the MAVS Coordinate System page.
• “Time Zone”: The time zone of the scene, as an integer offset from GMT. Positive = west, such that CST offset is 6.

Driver

"Driver":{ 
		 "Type":"A* Planner",
		 "Input File": "/media/sf_vm_shared/mavs/data/waypoints/example_waypoints.json",
		 "Number Processors":1,
		 "Update Rate":10.0
	}

Vehicle

"Vehicle":{
		"Type":"Rp3d",
		 "Input File":"full_path_to_vehicle.json",
		 "Number Processors":1,
		 "Initial Position":[0.0,0.0,0.0],
		 "Initial Orientation":[1.0,0.0,0.0,0.0],
		 "CG Height":2.0,
		 "Update Rate":20000.0
	}

• “Type”: The type of simulated vehicle. The allowed types are “Rp3d”, and “Chrono”
  • “Rp3d”: A lumped parameter vehicle dynamics implementation
  • “Chrono”: Vehicle simulated using the Chrono Vehicle simulator
• “Input File”: The input file associated with the vehicle model. Not that this is currently only used with the Chrono vehicle.
• “Number Processors”: This should typically be 1.
• “Initial Position”: The initial position of the vehicle in world ENU coordinates.
• “Initial Orientation”: Quaternion representing the initial orientation of the vehicle in world ENU coordinates.
• “CG Height”: The height of the vehicle CG above the ground in the static state. Used by the Car, Bicycle, and Turtle models.
• “Update Rate”: Frequency with which to step the vehicle simulation, in Hz.

Sensors

"Sensors": [
		{"Type": "camera", 
		 "Model":"XCD-V60", 
		 "Offset": [0.0, 0.0, 0.0],
		 "Orientation":[1.0, 0.0, 0.0, 0.0],
		 "Repitition Rate (Hz)":10.0, 
		 "Name":"camera", 
		 "Number Processors":1
		},

		{"Type": "gps", 
		 "Input File":"gps", 
		 "Offset": [0.0, 0.0, 0.0],
		 "Orientation":[1.0, 0.0, 0.0, 0.0],
		 "Repitition Rate (Hz)":10.0, 
		 "Name":"gps", 
		 "Number Processors":1
		},

		{"Type": "compass", 
		 "Input File":"compass", 
		 "Offset": [0.0, 0.0, 0.0],
		 "Orientation":[1.0, 0.0, 0.0, 0.0],
		 "Repitition Rate (Hz)":10.0, 
		 "Name":"compass", 
		 "Number Processors":1
		},

		{"Type": "lidar", 
		 "Model":"HDL-32E", 
		 "Offset": [0.0, 0.0, 0.0],
		 "Orientation":[1.0, 0.0, 0.0, 0.0],
		 "Repitition Rate (Hz)":10.0, 
		 "Name":"lidar", 
		 "Number Processors":1
		}
	]

Environment

See the MAVS Environment Parameters page for a description of these inputs.

Other Simulation inputs

 "Time Step":5e-05,
 "Max Sim Time":10.0,
 "Display Sensors":true,
 "Save Data":false,

The final result of these fields is shown below in example_input.json.

{ 
 "Scene":{
		 "Input File":"/media/sf_vm_shared/mavs/data/scenes/grass_maze.json",
		 "Origin": [32.3526,90.8779,73.152],
		  "Time Zone":6
	},

 "Driver":{ 
		 "Type":"A* Planner",
		 "Input File": "/media/sf_vm_shared/mavs/data/waypoints/example_waypoints.json",
		 "Number Processors":1,
		 "Update Rate":10.0
	},
 "Vehicle":{
		"Type":"Car",
		 "Input File":"",
		 "Number Processors":1,
		 "Initial Position":[0.0,0.0,0.0],
		 "Initial Orientation":[1.0,0.0,0.0,0.0],
		 "CG Height":2.0,
		 "Update Rate":20000.0
	},

 "Time Step":5e-05,
 "Max Sim Time":10.0,
 "Display Sensors":true,
 "Save Data":false,
 "Sensors": [
		{"Type": "camera", 
		 "Model":"XCD-V60", 
		 "Offset": [0.0, 0.0, 0.0],
		 "Orientation":[1.0, 0.0, 0.0, 0.0],
		 "Repitition Rate (Hz)":10.0, 
		 "Name":"camera", 
		 "Number Processors":1
		},

		{"Type": "gps", 
		 "Input File":"gps", 
		 "Offset": [0.0, 0.0, 0.0],
		 "Orientation":[1.0, 0.0, 0.0, 0.0],
		 "Repitition Rate (Hz)":10.0, 
		 "Name":"gps", 
		 "Number Processors":1
		},

		{"Type": "compass", 
		 "Input File":"compass", 
		 "Offset": [0.0, 0.0, 0.0],
		 "Orientation":[1.0, 0.0, 0.0, 0.0],
		 "Repitition Rate (Hz)":10.0, 
		 "Name":"compass", 
		 "Number Processors":1
		},

		{"Type": "lidar", 
		 "Model":"HDL-32E", 
		 "Offset": [0.0, 0.0, 0.0],
		 "Orientation":[1.0, 0.0, 0.0, 0.0],
		 "Repitition Rate (Hz)":10.0, 
		 "Name":"lidar", 
		 "Number Processors":1
		}
	], 
 "Environment": { 
 		 "Month": 3,
 		 "Day": 22,
 		 "Year": 2004,
 		 "Hour": 14,
 		 "Minute": 0,
 		 "Second": 0,
 		 "Turbidity": 3.0,
 		 "Local Albedo":[0.25,0.25,0.25]
	 }
 }