Publications
Collision avoidance system optimization with probabilistic pilot response models
Summary
Summary
All large transport aircraft are required to be equipped with a collision avoidance system that instructs pilots how to maneuver to avoid collision with other aircraft. Uncertainty in the compliance of pilots to advisories makes designing collision avoidance logic challenging. Prior work has investigated formulating the problem as a Markov...
Unmanned aircraft collision avoidance using continuous-state POMDPs
Summary
Summary
An effective collision avoidance system for unmanned aircraft will enable them to fly in civil airspace and greatly expand their applications. One promising approach is to model aircraft collision avoidance as a partially observable Markov decision process (POMDP) and automatically generate the threat resolution logic for the collision avoidance system...
Analytical workload model for estimating en route sector capacity in convective weather
Summary
Summary
We have extended an analytical workload model for estimating en route sector capacity to include the impact of convective weather. We use historical weather avoidance data to characterize weather blockage, which affects the sector workload in three ways: (1) Increase in the conflict resolution task rate via reduction in available...
A new approach for designing safer collision avoidance systems
Summary
Summary
The Traffic Alert and Collision Avoidance System (TCAS) has been shown to significantly reduce the risk of mid-air collision and is currently mandated worldwide on all large transport aircraft. Engineering the collision avoidance logic was a very costly undertaking that spanned several decades. The development followed an iterative process where...
Establishing a risk-based separation standard for unmanned aircraft self separation
Summary
Summary
Unmanned Aircraft Systems require an ability to sense and avoid other air traffic to gain access to civil airspace and meet requirements in civil aviation regulations. One sense and avoid function is self separation, which requires that aircraft remain "well clear." An approach is proposed in this paper to treat...
A space-time multiscale analysis system: a sequential variational analysis approach
Summary
Summary
As new observation systems are developed and deployed, new and presumably more precise information is becoming available for weather forecasting and climate monitoring. To take advantage of these new observations, it is desirable to have schemes to accurately retrieve the information before statistical analyses are performed so that statistical computation...
Triangle TCAS antenna
Summary
Summary
The Traffic Alert and Collision Avoidance (TCAS) provides a pilot display showing the range and bearing of nearby aircraft. TCAS obtains the bearing information by using an angle-of-arrival antenna. In the development of TCAS at Lincoln Laboratory, the first airborne tests were conducted using an Adcock antenna, which is a...
Partially-controlled Markov decision processes for collision avoidance systems
Summary
Summary
Deciding when and how to avoid collision in stochastic environments requires accounting for the likelihood and relative costs of future sequences of outcomes in response to different sequences of actions. Prior work has investigated formulating the problem as a Markov decision process, discretizing the state space, and solving for the...
Aircraft collision avoidance using Monte Carlo real-time belief space search
Summary
Summary
The aircraft collision avoidance problem can be formulated using a decision-theoretic planning framework where the optimal behavior requires balancing the competing objectives of avoiding collision and adhering to a flight plan. Due to noise in the sensor measurements and the stochasticity of intruder state trajectories, a natural representation of the...
Robust airborne collision avoidance through dynamic programming
Summary
Summary
The Traffic Alert and Collision Avoidance System (TCAS) uses an on-board beacon radar to monitor the local air traffic and logic to determine when to alert pilots to potential conflict. The current TCAS logic was the result of many years of development and involved the careful engineering of many heuristic...