Conflict Detection Metrics for Aircraft Sense and Avoid Systems

Abstract

Abstract:The task of an airborne collision avoidance system is to continuously evaluate the risk of collision and in the case of too high risk initiate an evasive action. The traditional way to assess risk is to focus on a critical point of time. A recently proposed alternative is to evaluate the cumulated risk over time. It is the purpose of this contribution to evaluate the difference between these two concepts and also to validate an approximate method for computing the cumulated risk, suitable for real-time implementations. For this purpose, random scenarios are generated from stochastic models created from observed conflicts. A realistic tracking filter, based on angle-only measurements, is used to produce uncertain state estimates which are used for risk assessment. It is shown that the cumulated risk is much more robust to estimation accuracy than the maximum of the instantaneous risk. The intended application is for unmanned aerial vehicles to be used in civilian airspace, but a real mid-air collision scenario between two traffic aircraft is studied as well.

Remotely piloted aircraft system with optimum avoidance maneuvers

“…14 The concept of CAS, including the discussion of the conflict detection issues with other aircrafts and anti-collision maneuvers of the UA were described by various authors. 11,12,[15][16][17][18][19][20][21] Related tasks concern stationary (ground) obstacle avoidance. The issue was discussed in the works of Kang 22 and Watanabe et al 23 Among the most important works, it is necessary to mention those within the frame of the SESAR 1 program and the MID-air collision avoidance system (MIDCAS) project.…”

Airborne Radar-Based Collision Detection and Risk Estimation for Small Unmanned Aircraft Systems

“…This event probability is then compared to a certain threshold above which the aircraft is deemed to be in collision. These probabilities can be estimated using approximate analytical solution [5], numerical approximation [39,40], or Monte Carlo methods [13,41,42]. The expected utility is another approach used to develop a risk alerting system that accounts for future changes in alerts and the responses to them [43].…”

Efficient Estimation of Probability of Conflict Between Air Traffic Using Subset Simulation

“…Probabilistic methods for conflict resolution requiring the calculation of metrics like the Probability of Conflict (P c ) have been discussed in [5]. Nordlund and Gustafsson [20] noted the huge number of simulations required to get sufficient reliability for small risks and suggested an approach that reduced the three dimensional problem to a one dimensional integral along piecewise straight paths [21], [22]. More recently, Jilkov et al have extended a method developed by Blom and Bakker [23] and estimated P c using multiple models for aircraft trajectory prediction [24].…”