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Sensors in AirSim

AirSim currently supports the following sensors. Each sensor is associated with a integer enum specifying its sensor type.

  • Camera
  • Barometer = 1
  • Imu = 2
  • Gps = 3
  • Magnetometer = 4
  • Distance Sensor = 5
  • Lidar = 6

Note : Cameras are configured differently than the other sensors and do not have an enum associated with them. Look at general settings and image API for camera config and API.

Default sensors

If no sensors are specified in the settings.json, then the following sensors are enabled by default based on the sim mode.

Multirotor

  • Imu
  • Magnetometer
  • Gps
  • Barometer

Car

  • Gps

ComputerVision

  • None

Behind the scenes, createDefaultSensorSettings method in AirSimSettings.hpp sets up the above sensors with their default parameters, depending on the sim mode specified in the settings.json file.

Configuring the default sensor list

The default sensor list can be configured in settings json:

"DefaultSensors": {
    "Barometer": {
        "SensorType": 1,
        "Enabled" : true,
        "PressureFactorSigma": 0.001825,
        "PressureFactorTau": 3600,
        "UncorrelatedNoiseSigma": 2.7,
        "UpdateLatency": 0,
        "UpdateFrequency": 50,
        "StartupDelay": 0

    },
    "Imu": {
        "SensorType": 2,
        "Enabled" : true,
        "AngularRandomWalk": 0.3,
        "GyroBiasStabilityTau": 500,
        "GyroBiasStability": 4.6,
        "VelocityRandomWalk": 0.24,
        "AccelBiasStabilityTau": 800,
        "AccelBiasStability": 36
    },
    "Gps": {
        "SensorType": 3,
        "Enabled" : true,
        "EphTimeConstant": 0.9,
        "EpvTimeConstant": 0.9,
        "EphInitial": 25,
        "EpvInitial": 25,
        "EphFinal": 0.1,
        "EpvFinal": 0.1,
        "EphMin3d": 3,
        "EphMin2d": 4,
        "UpdateLatency": 0.2,
        "UpdateFrequency": 50,
        "StartupDelay": 1
    },
    "Magnetometer": {
        "SensorType": 4,
        "Enabled" : true,
        "NoiseSigma": 0.005,
        "ScaleFactor": 1,
        "NoiseBias": 0,
        "UpdateLatency": 0,
        "UpdateFrequency": 50,
        "StartupDelay": 0
    },
    "Distance": {
        "SensorType": 5,
        "Enabled" : true,
        "MinDistance": 0.2,
        "MaxDistance": 40,
        "X": 0, "Y": 0, "Z": -1,
        "Yaw": 0, "Pitch": 0, "Roll": 0,
        "DrawDebugPoints": false
    },
    "Lidar2": {
        "SensorType": 6,
        "Enabled" : true,
        "NumberOfChannels": 16,
        "RotationsPerSecond": 10,
        "PointsPerSecond": 100000,
        "X": 0, "Y": 0, "Z": -1,
        "Roll": 0, "Pitch": 0, "Yaw" : 0,
        "VerticalFOVUpper": -15,
        "VerticalFOVLower": -25,
        "HorizontalFOVStart": -20,
        "HorizontalFOVEnd": 20,
        "DrawDebugPoints": true,
        "DataFrame": "SensorLocalFrame"
    }
},

Configuring vehicle-specific sensor list

A vehicle can override a subset of the default sensors listed above. A Lidar and Distance sensor are not added to a vehicle by default, so those you need to add this way. Each sensor must have a valid "SensorType" and a subset of the properties can be defined that override the default values shown above and you can set Enabled to false to disable a specific type of sensor.

"Vehicles": {

    "Drone1": {
        "VehicleType": "SimpleFlight",
        "AutoCreate": true,
        ...
        "Sensors": {
            "Barometer":{
                "SensorType": 1,
                "Enabled": true,
                "PressureFactorSigma": 0.0001825
            },
            "MyLidar1": {
                "SensorType": 6,
                "Enabled" : true,
                "NumberOfChannels": 16,
                "PointsPerSecond": 10000,
                "X": 0, "Y": 0, "Z": -1,
                "DrawDebugPoints": true
            },
            "MyLidar2": {
                "SensorType": 6,
                "Enabled" : true,
                "NumberOfChannels": 4,
                "PointsPerSecond": 10000,
                "X": 0, "Y": 0, "Z": -1,
                "DrawDebugPoints": true
            }
        }
    }
}

Sensor specific settings

For detailed information on the meaning of these sensor settings see the following pages:

Server side visualization for debugging

Be default, the points hit by distance sensor are not drawn on the viewport. To enable the drawing of hit points on the viewport, please enable setting DrawDebugPoints via settings json. E.g. -

"Distance": {
    "SensorType": 5,
    "Enabled" : true,
    ...
    "DrawDebugPoints": true
}

Sensor APIs

Jump straight to hello_drone.py or hello_drone.cpp for example usage, or see follow below for the full API.

Barometer

msr::airlib::BarometerBase::Output getBarometerData(const std::string& barometer_name, const std::string& vehicle_name);
barometer_data = client.getBarometerData(barometer_name = "", vehicle_name = "")

IMU

msr::airlib::ImuBase::Output getImuData(const std::string& imu_name = "", const std::string& vehicle_name = "");
imu_data = client.getImuData(imu_name = "", vehicle_name = "")

GPS

msr::airlib::GpsBase::Output getGpsData(const std::string& gps_name = "", const std::string& vehicle_name = "");
gps_data = client.getGpsData(gps_name = "", vehicle_name = "")

Magnetometer

msr::airlib::MagnetometerBase::Output getMagnetometerData(const std::string& magnetometer_name = "", const std::string& vehicle_name = "");
magnetometer_data = client.getMagnetometerData(magnetometer_name = "", vehicle_name = "")

Distance sensor

msr::airlib::DistanceSensorData getDistanceSensorData(const std::string& distance_sensor_name = "", const std::string& vehicle_name = "");
distance_sensor_data = client.getDistanceSensorData(distance_sensor_name = "", vehicle_name = "")

Lidar

See the lidar page for Lidar API.