Sensor

Author: Marcelo Jacinto (marcelo.jacinto@tecnico.ulisboa.pt)
License: BSD-3-Clause. Copyright (c) 2023, Marcelo Jacinto. All rights reserved.
Description: Definition of the Sensor class which is used as the base for all the sensors.

Classes:

Sensor

The base class for implementing a sensor
class pegasus.simulator.logic.sensors.sensor.Sensor

Bases: object

The base class for implementing a sensor

update_period

The period for each sensor update: update_period = 1 / update_rate (in s).

Type:

float

origin_lat

The latitude of the origin of the world in degrees (might get used by some sensors).

Type:

float

origin_lon

The longitude of the origin of the world in degrees (might get used by some sensors).

Type:

float

origin_alt

The altitude of the origin of the world relative to sea water level (might get used by some sensors)

Type:

float

Methods:

__init__(sensor_type, update_rate)

Initialize the Sensor class

config_from_dict(config_dict)

Method that should be implemented by the class that inherits Sensor.

initialize(vehicle, origin_lat, origin_lon, ...)

Method that initializes the sensor latitude, longitude and altitude attributes.

reset()

Method that when implemented, should handle the reset of the vehicle simulation to its original state

set_update_rate(update_rate)

Method that changes the update rate and period of the sensor

start()

Method that when implemented should handle the begining of the simulation of vehicle

stop()

Method that when implemented should handle the stopping of the simulation of vehicle

update(state, dt)

Method that should be implemented by the class that inherits Sensor.

update_at_rate()

Decorator function used to check if the time elapsed between the last sensor update call and the current sensor update call is higher than the defined update_rate of the sensor.

Attributes:

sensor_type

(str) A name that describes the type of sensor.

state

(dict) A dictionary which contains the data produced by the sensor at any given time.

update_rate

(float) The rate at which the data in the sensor should be refreshed (in Hz).
__init__(sensor_type, update_rate)

Initialize the Sensor class

Parameters:

  • sensor_type (str) – A name that describes the type of sensor

  • update_rate (float) – The rate at which the data in the sensor should be refreshed (in Hz)

config_from_dict(config_dict)

Method that should be implemented by the class that inherits Sensor. This is where the configuration of the sensor based on a dictionary input should be performed.

Parameters:

config_dict (dict) – A dictionary containing the configurations of the sensor

initialize(vehicle, origin_lat, origin_lon, origin_alt)

Method that initializes the sensor latitude, longitude and altitude attributes.

Note

Given that some sensors require the knowledge of the latitude, longitude and altitude of the [0, 0, 0] coordinate of the world, then we might as well just save this information for whatever sensor that comes

Parameters:

  • vehicle (Vehicle) – A reference to the vehicle that this sensor is associated with

  • origin_lat (float) – The latitude of the origin of the world in degrees (might get used by some sensors).

  • origin_lon (float) – The longitude of the origin of the world in degrees (might get used by some sensors).

  • origin_alt (float) – The altitude of the origin of the world relative to sea water level (might get used by some sensors).

reset()

Method that when implemented, should handle the reset of the vehicle simulation to its original state

set_update_rate(update_rate)

Method that changes the update rate and period of the sensor

Parameters:

update_rate (float) – The new rate at which the data in the sensor should be refreshed (in Hz)

start()

Method that when implemented should handle the begining of the simulation of vehicle

stop()

Method that when implemented should handle the stopping of the simulation of vehicle

update(state, dt)

Method that should be implemented by the class that inherits Sensor. This is where the actual implementation of the sensor should be performed.

Parameters:

  • state (State) – The current state of the vehicle.

  • dt (float) – The time elapsed between the previous and current function calls (s).

Returns:

(dict) A dictionary containing the current state of the sensor (the data produced by the sensor)

update_at_rate()

Decorator function used to check if the time elapsed between the last sensor update call and the current sensor update call is higher than the defined update_rate of the sensor. If so, we need to actually compute new values to simulate a measurement of the sensor at a given rate.

Parameters:

fnc (function) – The function that we want to enforce a specific update rate.

Examples

>>> class GPS(Sensor):
>>>    @Sensor.update_at_rate
>>>    def update(self):
>>>        (do some logic here)
Returns:

This decorator function returns None if there was no data to be produced by the sensor at the specified timestamp or a dict with the current state of the sensor otherwise.

Return type:

[None, Dict]

property sensor_type

(str) A name that describes the type of sensor.

property state

(dict) A dictionary which contains the data produced by the sensor at any given time.

property update_rate

(float) The rate at which the data in the sensor should be refreshed (in Hz).