199. System Signal

The system_signal monitors various vehicle system signals and raises an issue when a signal remains in a specific, user-defined state. This framework is designed to be extensible, allowing users to monitor both standard vehicle indicators and custom properties.

The modifier contains three example checkers:

• lights_signals_checker: Monitors the vehicle's turn signals.
• hazard_lights_checker: Monitors the vehicle's hazard lights.
• additional_properties_checker: Monitors a custom signal from the vehicle's additional_properties list, which is useful for evaluating proprietary or non-standard system data, often from log replay scenarios.

A new interval is triggered each time a monitored signal enters one of the configured signal_states and continues until the signal transitions to another state. The lights_signals_checker and hazard_lights_checker use the vehicle.state.vehicle_indicators struct to retrieve information on the vehicle's sensors. The additional_properties_checker should use the vehicle.state.additional_properties list, so the signal_name parameter must match one of the items in this list.

The signal_states list varies according to the monitored signal, and is user-customizable. The checkers will raise an issue when the state is in the issue_states list, which is the list of states that raise issues when entered and also user-customizable. The severity of the raised issues (issue_severity) is also user-customizable.

The user can configure whether a checker is enabled by default by setting the enable parameter accordingly.

199.0.1 Start condition

The system_signal monitors the signals at each top.clk. An interval begins when a signal's current state is found within the configured signal_states list and continues until the signal transitions to another state.

199.0.2 End condition

An interval is closed as soon as the signal's state changes or is no longer a member of the configured signal_states list. The while_w construct automatically terminates the interval when the trigger condition is no longer met at the next top.clk.

199.1 Plot

199.2 Attributes

The following attributes define the behavior and characteristics of the evaluator.

199.3 Configuration parameters

The following parameters can be configured to customize the evaluator's behavior.

199.4 Metrics

The following metrics are recorded and tracked by the evaluator.

199.5 Log and Error Messages

199.6 Usage

199.6.1 How to instantiate

The system signals framework is built into the Ego only, via global modifier sut_vehicle.system_signal. It contains three checkers:

• lights_signals_checker — monitors turn signals (vehicle_indicators.turn_signal_state)
• hazard_lights_checker — monitors hazard lights (vehicle_indicators.hazard_lights)
• additional_properties_checker — monitors a custom protobuf property (additional_properties, matched by signal_name)

You do not instantiate the checkers with constructor parameters in scenario OSC.

199.6.2 Set parameters at instantiation time

Each checker has its own system_signals_checker_config instances in ftlx_global_eval_config:

• ego_light_signals_checker_config — turn signals (default: monitor only, issue_severity = ignore)
• ego_hazard_lights_checker_config — hazard lights (default: issue on active, severity warning)
• ego_additional_properties_checker_config — custom signal (default: disabled, example signal occlusion)

199.6.3 Define and use a custom parameter set

Apply a custom config globally To customize a checker for all scenarios, create a config instance and apply it via ftlx_global_eval_config. The following example customizes the hazard lights checker. Create a config instance:

const custom_hazard_config: system_signals_checker_config = new
set custom_hazard_config.signal_name = "hazard_lights_status"
set custom_hazard_config.signal_states = ["active", "off"]
set custom_hazard_config.issue_states = ["active"]
set custom_hazard_config.issue_severity = error
set custom_hazard_config.enabled = true

extend ftlx_global_eval_config:
    set ego_hazard_lights_checker_config.signal_states = custom_hazard_config.signal_states
    set ego_hazard_lights_checker_config.issue_states = custom_hazard_config.issue_states
    set ego_hazard_lights_checker_config.issue_severity = custom_hazard_config.issue_severity

Customize per scenario To override fields for a specific scenario, extend the modifier directly. The fields are bound to the config by default:

extend sut_vehicle.system_signal:
    keep(issue_states_hazard_lights == ["active"])
    keep(signal_states_lights_signals == ["off", "left_on", "right_on", "unknown"])

199.6.4 Disabling the checker

• To disable a single checker:

  extend ftlx_global_eval_config:
      set ego_light_signals_checker_config.enabled = false
  

• To disable the checkers at runtime:

  extend sut_vehicle.system_signal:
      on @start:
          override(lights_signals_checker, run_mode: freeze)
          override(hazard_lights_checker, run_mode: freeze)
          override(additional_properties_checker, run_mode: freeze)
  

199.7 Additional information

All parameters are required, but you don't need to customize all of them. For any parameter you don't customize with set, the default value defined in system_signals_checker_config is used. The modifier can raise the following issues.