GPS World

Tag: Fault Tree Analysis

  • UAV Navigation defines operational envelope for VECTOR-600 autopilot

    UAV Navigation defines operational envelope for VECTOR-600 autopilot

    An independent study conducted by UAV Navigation has defined the operational envelope of the VECTOR-600 autopilot based on the Specific Operations Risk Assessment (SORA) methodology. The operational envelope defines the operational risk profile within which an aircraft can operate safely, taking into consideration all risk mitigations included within the system.

    The SORA methodology evaluates the safety risks involved with the operation of an unmanned aerial system (UAS) of any class, size or type of operation. The concept of operation (ConOps) is normally used as the input for this analysis; the output takes the form of the Specific Assurance and Integrity Level (SAIL) for a particular operation, which indicates the level of robustness that must be demonstrated for the operational safety objectives.

    In this case, instead of performing a conventional SORA analysis from the ConOps to the SAIL output, this study was performed the other way around because the objective of the study was to identify the operational envelope of the sytem.

    EUROCAE ED-280, the guidelines for UAS safety and analysis for specific categories of low and medium levels of robustness, recommends to any operator a detailed definition of different mission and platform points: the ConOps, the entire UAS architecture including functions, systems, and implementation, identification and classification of failure conditions; verification that safety objectives are fulfilled and a complete probable failure analysis using FMEA-like techniques and Fault Tree Analysis (FTA).

    UAV Navigation prepared an FMECA and FTA analysis performed by a third-party and independent company on the VECTOR-600 autopilot and its onboard sensor suite, the POLAR-300. The study concluded that within the operational envelope of the VECTOR-600, any failure – however remote the probability – is highly unlikely to result in a catastrophic outcome, such as the loss of the aircraft. The conclusions reached indicate that the system is perfectly suited for VLOS/BVLOS operations – including appropriate restrictions where applicable. The system has proved its robustness and suitability for safe operations over a wide range of missions usually performed by professional UAS.

    The analysis is available on request to all clients interested. Contact UAV Navigation for more information.

    Photo: UAV Navigation
    Photo: UAV Navigation
  • UAV Navigation puts Vector-600 autopilot through paces

    UAV Navigation puts Vector-600 autopilot through paces

    The Vector-600 autopilot. (Photo: UAV Navigation)
    The Vector-600 autopilot. (Photo: UAV Navigation)

    UAV Navigation has confirmed the safety and reliability of its Vector-600 autopilot for civil applications with an independent study. The study was performed as part of the European Union VaNeT project, and conducted by third-party company Anzen Engineering.

    An autopilot system in an unmanned aerial vehicle (UAV)  is the heart of the flight control system. For the Vector-600, the study included a reliability prediction report (RPR), failure mode effects and criticality analysis (FMECA) and fault tree analysis (FTA).

    Reliability Prediction Report. The RPR analyzes probability of failure of every single sensor and component inside a system. It helps define component failure rates and, consequently, a prediction of the time that the VECTOR-600 is expected to operate free of failures under given operating conditions. According to this, the VECTOR-600 has shown a mean time between failures of more than 19,500 hours.

    Failure Mode Effects and Criticality Analysis. A FMECA study identifies potential failures of system functions and assesses their effects, so that mitigation actions can be defined. It is a bottom-up analysis considering each single elementary failure mode and assessing its effects.

    Fault Tree Analysis. Fault trees are a classic deductive analysis technique useful for both qualitative and quantitative analysis. For the Vector-600, a quantitative FTA provided probability estimates for major hazards, as well as identifying single-point failure modes and guiding further design for hazard reduction. According to the results, Vector-600 showed a probability of loss of mission per flight hour of 1,809E-05 under its operating conditions.

    “The FMECA, RPR, and FTA analysis performed by the external and independent company Anzen have proven that our most advanced autopilot, Vector-600, is one of the most reliable GNC [guidance, navigation and control] systems for NATO Class I and II unmanned aircrafts available in the market and enables our clients to execute missions ensuring safety,” UAV Navigation stated in a press release.

    The EU regulation framework defines three classes of operations: open, specific and certified. In specific and certified category operations, including most professional UAS flights, operators and aircraft manufacturers need to prove safe operation of their platforms. For this reason, the study of the reliability of the systems involved in the UAV becomes a must to demonstrate the system can operate free of failures under specific operational conditions.

    The full analysis report is available on request.