Verification

Verification is the process of confirming that a product, system, or component meets specified requirements. Verification ensures that each stage of the development lifecycle correctly implements the requirements of the previous stage.

For instance, if a design specifies a certain behavior for an autonomous driving system, verification activities would confirm that the implemented code truly exhibits that exact behavior. This is crucial because errors introduced early in the development process can propagate and become much more difficult and costly to fix later, potentially leading to systematic faults and unsafe conditions.

Verification encompasses a wide range of activities throughout the development lifecycle. Common examples include reviews, inspections, walkthroughs, and various types of testing.

• Code reviews, for instance, involve engineers systematically examining source code to identify defects and ensure adherence to coding standards and design requirements.

• Static analysis, another key verification activity, uses specialized software tools to analyze code without executing it, checking for potential vulnerabilities, coding errors, and rule or standard compliance.

• Dynamic testing, such as unit testing, integration testing, and system testing, involves executing the software to observe its behavior and confirm it operates as intended under various conditions.

• In the automotive domain, hardware-in-the-loop (HIL) testing is a sophisticated verification method where real hardware components are tested against simulated environments to ensure proper interaction, timing and functional behavior.

Verification must be performed with utmost care because it directly impacts the safety and reliability of safety-critical systems. The goal is to detect and address errors as early as possible in the development process. If errors are not caught during verification, they can lead to system malfunctions, failures, and potentially hazardous situations in the final product.

For example, an unverified control algorithm in an automotive braking system could lead to unpredictable braking behavior. ISO 26262 emphasizes rigorous verification activities with defined methods and confidence levels to ensure that all safety requirements are met and that residual risks are reduced to an acceptable level. Proper verification provides the necessary assurance that the system will perform its intended safety functions under all specified operating conditions.

Verification and Validation are distinct but complementary processes in functional safety. While verification checks adherence to specifications and requirements, validation ensures that the final product meets the user's needs and intended purpose in its operational environment.

For example, verification might confirm that a radar sensor’s software accurately processes raw data according to its design specifications.

Validation, conversely, would involve testing the autonomous driving system in representative real-world scenarios to confirm that the sensor data, as processed by the software, correctly contributes to safe navigation and obstacle detection for the end-user.

Both verification and validation are essential for achieving functional safety, working in tandem to build a reliable and safe system that not only works correctly but also effectively fulfills its safety objectives.

The distinction can be expressed as follows:

• Verification: Ensures the system is built according to its specified design and requirements.

• Validation: Confirms that the completed system fulfills its intended purpose and achieves the required safety outcomes.

Verification is fundamental to achieving functional safety under ISO 26262. The standard mandates specific verification activities at each stage of the automotive safety lifecycle, from concept phase to production and operation. It specifies the methods, techniques, and confidence levels required for various development artifacts based on their Automotive Safety Integrity Level (ASIL). For instance, for higher ASILs, more rigorous and independent verification methods are typically required.

ISO 26262 also emphasizes the independence of verification activities, meaning that the team performing verification should ideally be organizationally or functionally independent from the team that developed the item. This independence helps ensure objectivity and thoroughness in identifying defects.

By systematically applying verification processes and documenting the results, organizations can demonstrate that their safety-critical systems meet the stringent requirements of ISO 26262, fostering trust in the reliability and safety of their automotive products.