Trajectory-Based Operations (TBO) - Joint Planning and ...

Trajectory-Based Operations (TBO)
Study Team Report
Trajectory operations are enabled by improved utilization of current and emerging aircraft
capabilities—Area Navigation/Required Navigation Performance (RNAV/RNP), FMS, ADS-B, and
data communications—and improvements in ground automation/infrastructure: data communications,
surveillance, net-centric data operations, and ANSP and Flight Operations Center (FOC) automation.
Surveillance accuracy using ADS-B has a direct functional relationship to improved navigation
performance accuracy because ADS-B uses the same GNSS source. These enablers result in increased
accuracy of the aircraft surveillance information, increased accuracy in navigation of the intended path,
new capabilities to deliver clearances more efficiently and accurately, and increased timeliness in
executing an Air Traffic Control (ATC) clearance or meeting an aircraft-specific flow constraint. As a
result, the trajectory is more accurate in execution and more predictable in time and
position. Improvements in trajectory precision can then lead to reductions in separation and manage
more aircraft in the airspace. These improvements are leveraged through system-wide sharing of
information with all authorized users via net-centric data operations and data communications with the
aircraft. Better information and seamless information access provide the users and operators of the
NAS with common awareness, a more accurate view of the system, and improved decision-making.
While trajectory operations begin with limited capabilities focused mainly on using TBO strategically,
TBO rounds out the performance capabilities by incorporating tools and procedures to implement gateto-gate
use of trajectories for both strategic and tactical management of operations. TBO is the use of
4DT for planning, sequencing, spacing, and separation based on where the aircraft will be, with
measured progress and conformance to its clearance, and using ground automation in determining and
de-conflicting downstream flows of aircraft.
TBO is based on a significant change in separation. Today, there is procedural separation involving
position reporting when outside of the surveillance area of the ANSP. In the presence of surveillance,
aircraft are separated based on their known position. Under TBO, current position is still used, but
separation is based on where the aircraft is and where the aircraft will be at a time in the future. This is
why conformance monitoring is important. The progress toward that point in space at a time in the
future must be tracked to separate based on TBO.
3.0 Definition of Terms
Trajectory Operations – The concept of an ATM system in which every aircraft that is operating in
or managed by the system is represented by a 4DT. Every managed aircraft known to the system has a
4DT either provided by the user or derived from a flight plan or type of operation. Trajectory
operations, or TOps, represent a mid-term implementation strategy to gain capacity and efficiency.
Trajectory-Based Operations – Extends TOps and provides separation, sequencing, and merging and
spacing of flights based on a combination of their current and future positions. TBO operates gate-togate,
extending benefits to all phases of flight operations. TBO uses the 4DT to both strategically
manage and tactically control surface and airborne operations. Aircraft are handled by their trajectory.
4DT – Defined laterally and longitudinally by latitude and longitude, vertically by altitude and with
time. Surface movement is a 3DT—lateral, longitudinal, and time.
Joint Planning and Development Office
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