8
.
G
I
S
r
e
p
r
e
s
e
n
t
a
t
i
o
n

GIS was used for representing the trajectories imported and merged. It allowed checking the inventory as shown in Figure 18. This example shows the incorrect merge of several flights leading to a flight lasting for a day. After reviewing the merge process, two of the flights previously merged incorrectly are now identified separately.

Figure 18: Identification of a dubious flight visualized in GIS before and after solving the problem.

9
.
I
m
p
r
o
v
e
d
G
r
e
a
t
C
i
r
c
l
e
t
r
a
j
e
c
t
o
r
y
g
e
n
e
r
a
t
o
r

9.1. Introduction
The migration of the tool developed in Access to Oracle resulted in reviewing and
improving the Great Circle trajectory generator.

Schedule type of data such as data obtained from Back Aviation for the rest of the world
do not own any information on the trajectory flown by the aircraft between the airport of
departure and the airport of destination. The inventory consists of supplying coordinates
(latitude/longitude/altitude and time) of points along the trajectory so that emissions can
be calculated at a given time and location.

Resulting of this lack of information on the flight trajectory, two options were retained to
attribute a trajectory to a flight:

Use of existing trajectory from ETMS or AMOC if one exists.
Use of route network, waypoints and aircraft performance defined from existing trajectory.

These two options were developed as two methods respectively named:

.  
Method 1: City-pair-based trajectory.

.  
Method 2: Profile-based trajectory.

The first method is related to the existing in AMOC or ETMS of a trajectory, which is used and fitted to the city-pair without trajectory as identified in Back Aviation. This is done taking into account the aircraft type. The second method is based on the use of ETMS flight data for modeling aircraft performance profiles and the knowledge of the route network for calculating missing coordinates.

9.2. Method 1: City-pair-based trajectory
Method 1 is based on the existing of the city-pairs studied in the AMOC-ETMS inventory. It can be divided into two cases. For the city-pair studied, either the aircraft type mentioned in the schedule type of data is the same than in the AMOC-ETMS inventory or the aircraft type mentioned is different.
Case A: the aircraft type is the same
If the city-pair studied and the aircraft type are represented in the AMOC-ETMS inventory, the flight with the departure time as close as possible to the scheduled time is chosen. The time spent (.T) for flying from the airport of departure (ADEP) to the airport of arrival
(.Tsched
(ADES) is calculated using respectively schedule information ADEP-ADES) and inventory information (.Tinv ADEP-ADES).
.TADEP-ADES = arrival time -departure time
Both schedule (.TschedADEP-ADES) and merged (.Tinv ADEP-ADES) inventory times are then compared. According to the result, two options exist (Table 34):
.  
If both variations of time are equal, then the flight legs from the merged inventory are selected and implemented into the schedule data. The time of each position is recalculated in function of the departure time, the position of the points are kept.

.  
If the variations of time are different, first the time of arrival of the schedule data is recalculated with the inventory time variation and then the flight legs are selected and implemented in the schedule data.
　
中國航空網 www.k6050.com
航空翻譯 www.aviation.cn
本文鏈接地址：AERO2K Flight Movement Inventory Project Report(29)