Exploring and Validating the Altitude Reporting Trajectory Update Algorithm for TCAS in Dense Airspace

The swift advancement of eVTOL aircraft, diverse UAVs, helicopters, and civilian airliners like the C919 has significantly increased airspace congestion, thereby elevating flight safety risks. Equipping aircraft with TCAS emerges as a viable solution to this challenge. This paper utilizes Matlab to simulate the core technology of TCAS: trajectory updating. We have constructed a flight scenario with an airspace density of 0.3 aircraft per square nautical mile and conducted simulation experiments using the altitude reporting trajectory update algorithm. The paper delves into the impact of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$a$</tex> and β parameter selection on trajectory update errors and introduces a method to ascertain optimal <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$a$</tex> and β parameters. This method considers the average error and variance between estimated and target values for the target aircraft's range and altitude, alongside the relationship among reply range, reply altitude, and time. Simulation results indicate that the altitude reporting trajectory update algorithm can accurately match replies to the correct trajectory in high-density scenarios, effectively achieving trajectory updating. The findings of this paper hold immense significance for ensuring safe flight operations in aircraft equipped with TCAS.