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AwSim
is a general-purpose trajectory simulator aimed at providing
a realistic air traffic data source for ATC/ATM systems that can be
used in the areas of testing, modeling and training.
Trajectory Simulation
The main output produced by
AwSim is a stream of trajectories
(i.e. objects encapsulating a 4-dimensional profile of a moving
vehicle in an Earth center coordinate system). The segments from which
trajectories are built can be made to snap to an airspace structure
(i.e. aerodromes, fixes and airways) or alternatively, they can be
generated in a free-flight unrestricted fashion. The user can set the
parameters that control the statistical distribution functions from
which the population of segments is drawn. The variables under control
(all of which have their separate distribution function) are: segment
speed, segment length, Gaussian transverse deviation, segment
altitude, start and end location of the trajectory, number of segments
in a trajectory, and start time.
When generating trajectories,
AwSim randomly chooses the departure
and arrival aerodromes based on a prepared aerodrome table that
includes the airport capacity and optionally a 'hub' designator (which
allows it to be connected to any other 'hub' airport). For a non-hub
airport, AwSim
accepts for each airport the list of its connecting
airports along with relative traffic weight. Thus, for instance one
can configure a non-hub airport A, connecting (i.e. accepting flights
between) three other airports B (30%), C (25%), and D (45%) with the
fraction of the traffic split as indicated by the percent figures.
A time weighing function allows the controlling of the traffic load
depending on the time of day. This time function together with the
traffic coefficients for each airport allows for a very flexible and
realistic control of the generated traffic patterns.
The AwSim
output port writes trajectories by default, but it also
has the option of writing text messages (i.e. ICAO flight plans)
suitable for sending via AFTN or message gateway of any ATC system. In
this manner AwSim
can be used as a source of input for any ATC/ATM
system.
Conflict Prediction
The AwSim Conflict Prediction (CPR)
process examines the AwSim
trajectories (or trajectories from other sources) and determines if
any violations of the separation rules exists. CPR provides the
relevant conflict data to AwSim
metrics application for display and comparison purposes.
CPR applies the U.S. domestic separation rules of
5nm lateral separation, 10 or 20 FL vertical, depending on altitude,
or other adaptable parameters. CPR provides an option to use block
altitudes, or to interpolate altitudes during climb/descent.
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