| Abstract | Transport Canada (TC) and NRC have identified several key areas of technology performance evaluation that are required to enable safe Remotely Piloted Aircraft System (RPAS) operations conducted Beyond Visual Line of Sight (BVLOS); a key area that has been identified is RPAS detect and avoid (DAA) capability. Advancing technology performance assessment in this area will help guide operational risk assessments for future BVLOS SFOC applications as well as inform regulatory developments.
In 2020 TC, LookNorth, and NRC conducted an initial investigation into operator/integrator developed ground based DAA systems that involved the operators conducting flight tests of their systems, and providing the data to NRC for analysis. The results published in 2021indicated a desire to improve the consistency of data collection and test design, as well as to collect more data regarding airborne DAA systems. As a result, TC performed a targeted call for participation to industry, which targeted technologies/systems with detection technology onboard of the Remotely Piloted Aircraft (RPA). This project differs from the previous DAA evaluation project (LookNorth/TC 2021), as mounting each DAA system onboard a single traditional aircraft ensured known and common test conditions.
National Research Council Canada and Transport Canada obtained participation from 3 airborne DAA system manufacturers with different sensor modalities (1 electro-optical and 2 radar-based). The selected systems were integrated onto the NRC Bell 205 airborne simulator medium utility helicopter, and a series of 80 flight test points were conducted using the NRC Mk IV Harvard, and Bell 206 Jetranger as instrumented Intruder aircraft.
This report provides an overview of each of the systems tested including a description of the hardware and software integration of the DAA systems on board the NRC Bell 205 as well as the supporting systems developed to facilitate the conduct of ‘near miss intercepts’. An overview of the flight test plan, the associated techniques, and the test objectives is then provided. Next, the report breaks out the integration and test performance aspects of the individual systems. Finally, the combined system performance is presented followed by conclusions and recommendations. None of the sensors tested can be considered as complete ‘plug-and-play’ systems. The task of having to integrate three sensors to a single airborne platform highlighted the fact that there is no common interface standard definition for DAA sensors. Moreover, the three sensors tested required different degrees of integration and levels of familiarity with the basic sensing modality and its associated parameters.
All sensors exhibited average detection ranges that were comparable with the manufacturer’s published specifications, however the variance between intercepts was significant. It is conjectured that this variance will have an impact on the realized risk ratio of the DAA system. The range at first detection performance achieved for the closing rates tested yielded a time to closest approach of 20 to 40 seconds on average. These values are low if the decision making loop requires human intervention. If the DAA system requires human intervention, the delay times should be accounted for in any modelling effort used to assess the full system risk ratio. The salient conclusion from this flight testing is that the performance results are highly dependent on the quality of the system integration. Moreover, one cannot conduct a performance assessment of the sensor alone without considering the integration into the greater system. The importance of flight testing DAA systems for RPAs cannot be overstated, as it is the ultimate validation of functionality and effectiveness of these systems in real-world scenarios, allowing both the operator and regulator to understand the degree to which DAA systems can mitigate the air risk. The airborne testing of three DAA sensors described in this report highlights the importance of flight testing for both system performance validation as well as system integration testing and development. Each integration of a DAA sensor into a specific RPAS and airspace (i.e. traffic distribution) will require a separate assessment of risk ratio. This highlights the need for a well established and agreed upon means for integrators to calculate the risk ratio. |
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