Sensor modeling options

Control over sensor behaviors is provided by both sensor specifications and the SensorModel class. Gyroscopes and accelerometers share common enough operating principles that the same model can be applied to both.

By default, all supported behaviors are simulated.

For an effect to be seen on the sensor measurement, both the corresponding specification and the model option boolean must be set. If the specification value is left unset, it defaults to zero (or identity) so the behavior will be simulated but it will have no effect.

Errors are applied as per Standard [05], Section 8.3. Misalignment causes the true motion of the device to be sensed along misaligned sensing axes. Input limits, biases, and noise, represent the effects of physical and digital processes superimposed on the true input. Scaling errors and digital quantization then affect the final output.

The default SensorModel options are show below:

from inertialsim.sensors import SensorModel

# Initialize the sensor model
model = SensorModel()
# Default data interface options
model.data_interface.simulate_sample_rate = True
model.data_interface.simulate_quantization = True
model.data_interface.simulate_delta_outputs = False
# Default axis misalignment options
model.misalignment.simulate_random = True
# Default input limits options
model.input_limits.simulate_minimum = True
model.input_limits.simulate_maximum = True
# Default bias options
model.bias.simulate_fixed = True
model.bias.simulate_random = True
model.bias.simulate_temperature = True
# Default random noise options
model.noise.simulate_quantization = True
model.noise.simulate_random_walk = True
model.noise.simulate_bias_instability = True
model.noise.simulate_rate_random_walk = True
model.noise.simulate_rate_ramp = True
# Default scale factor options
model.scale_factor.simulate_fixed = True
model.scale_factor.simulate_random = True

IMU Model

The IMUModel is a composite that includes two [SensorModel] instances and a single data interface section. This allows for separate model options to apply to gyro and accelerometer sensors in the IMU.

from inertialsim.sensors.imu import IMUModel

# Initialize the sensor model
model = IMUModel()
# Default data interface options
model.data_interface.simulate_sample_rate = True
model.data_interface.simulate_quantization = True
model.data_interface.simulate_delta_outputs = False
# Gyro defaults are same as SensorModel()
model.gyro
# Accelerometer defaults are same as SensorModel()
model.accelerometer

<inertialsim.sensors._sensor.SensorModel at 0x110c04740>