En-Route Automation Modernization (ERAM) trajectory model evolution to support trajectory-based operations (TBO)

The En Route Automation Modernization (ERAM) system is the Federal Aviation Administration's (FAA) automation platform used to manage air traffic at 20 en route centers in the US. This paper describes the trajectory model in the currently operational ERAM system and presents an approach to enhance ERAM's aircraft performance model with a high fidelity kinetic capability that can provide greater consistency with the guidance trajectory generated by Flight Management Systems (FMS). ERAM has a parametric trajectory predictor that uses static aircraft data. A physics-based kinetic trajectory predictor, on the other hand, can exploit flight-specific aircraft intent that will become increasingly available as the Operational Improvements in the Next Generation Air Transportation (NextGen) system are deployed. Additionally, a kinetic model will provide increased interoperability between air traffic management systems. A kinetic aircraft performance model for ERAM has been prototyped and evaluated. When flight-specific intent information is available or can be derived, the accuracy of predicting the top of descent (TOD) is significantly improved with a kinetic model. An ERAM test run with the kinetic prototype based on recorded traffic of 50 flights executing idle thrust descents shows that, relative to the baseline ERAM legacy system, the number of trajectories with along-track TOD prediction errors less than 5 nautical miles increases from 9% to 63%. Considering the incremental nature of the NextGen implementation, a low risk approach to evolving ERAM is to first move to a hybrid kinetic-parametric trajectory model, where current parametric modeling is retained and kinetic modeling is performed when flight-specific intent is available.