Analysis of induced Traffic Alert and Collision Avoidance System collisions in unsegregated airspace using a Colored Petri Net model

Abstract

For rigorously safe aviation, it is of great significance to conduct an analysis of the current and new operations, providing a global perspective of the scenario dynamics and a better understanding of the potential collision occurrence for risk assessment. The objective of this study is to consider a number of the difficulties that are involved when establishing a validation of the Traffic Alert and Collision Avoidance System (TCAS), which constitutes the last resort for reducing the risk of near mid-air collisions between aircraft in a multithread scenario, and to analyze the TCAS logic using a causal model. In this paper, the causal model that is specified in the Colored Petri Net (CPN) formalism is employed as a key approach to analyze quantitatively the state space of a congested traffic scenario in which the events could transform a conflict into a potential collision. It offers a rigorous tool not only for TCAS validation but also for the analysis of a wide range of properties of the TCAS behavior. This CPN model assumes unrestrained initial positions and TCAS II-equipped aircraft; it is demonstrated to be extremely effective for generating all possible future TCAS failure end-states from the current locations, and the Interactive Collision Avoidance Simulator EuroControl simulator is used to illustrate the collision process of a three-aircraft scenario.

Cooperative conflict detection and resolution of civil unmanned aerial vehicles in metropolis

“…When aircrafts are predicted to lose separation in miles, Traffic alert and Collision Avoidance System (TCAS)-II would coordinate with neighboring planes to find maneuvers with least hazard. 11 When it comes to freeflight mode, onboard algorithms are devised to find the conflict-free solutions for multiple planes. 12,13 There are also many researches on UAVs' CD&R problem.…”

“…In order to solve this nonlinear optimization efficiently, we make further discussion on the safe separation constraint. We obtain the equation d(j i , j j ) = r ij s from inequality (11). The equation is expanded as…”

Extended Traffic Alert Information to Improve TCAS Performance by means of Causal Models

“…It is used as a causal analysis model to improve the TCAS avoidance performance in dense air traffic. collision also could emerge especially in the dense air traffic [2][3][4][5][6][7][8][9]. Therefore, based on the mathematical model presented in the previous section, a causal analysis model in CPN formalism is critical for the CA process of multiple aircraft.…”

“…(3) Although there would be a large number of aircraft in the entire airspace, the aircraft number to be considered by TCAS is limited to a restricted range of the own aircraft. A highly efficient method for avoiding computational redundancies in the state space is clustering, which reduces the general problem to several sets of independent scenarios (known as clusters [8], just as the four-aircraft scenario in this paper) in a partial scope. It means that there may be several aircraft as the surrounding traffic of the four aircraft, but they have been ignored because they have no direct influence on TCAS performance neither in the cluster results.…”

“…Their study results quantitatively indicate the variation of risk ratio which measures how the probability of an NMAC changes when an aircraft is equipped with TCAS versus being unequipped. Besides, in our previous research [8,9], the causal encounter models have been proposed and improved to identify TCAS weaknesses (potential collision) by predictively generating the flyable scenario for a specific scenario, and the relationship between potential collisions and different pilot delays has been displayed.…”