Estimation of alerting thresholds for Sense-and-Avoid

In this paper, a method to calculate alerting thresholds is outlined along with the assumptions and an example. First, the definitions and recommendations of the FAA sponsored Sense-and-Avoid (SAA) workshop report has been adapted to a formal mathematical definition. These definitions are then realized using assumptions and other logic and are translated into a more concrete SAA scenarios. Alerting threshold is first calculated as a range-based specification and then translated into a time-based specification using time to closest point of approach (CPA). It is shown that both, range and time based thresholds can serve important roles in the development of a SAA systems as well as development of the minimum performance standards for SAA. The range-based threshold can be used to define the baseline sensor specification and the time-based threshold can be used as the minimum CPA for collision avoidance. An example of calculating collision avoidance threshold (CAT) for level-turn maneuvers of the unmanned aircraft (UA) is presented along with the results.