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Condition 3 (Figure 17) applies if condition 2 is true. It avoids that short flights flying several time in a day (same callsign and airport of departure/arrival) be merged. If the three following criteria are checked and true, then the merge is cancelled:

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If the difference of event times between the sets of flight legs of the two flights is less than 15 minutes.

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And if the difference (in absolute value) of time between the last event time and first event time of the first flight is higher than an hour.

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And if the difference (in absolute value) of time between the fist event time of the second flight and the last event time of the first flight is higher or equal to half of the difference of time between the last event time and first event time of the first flight.

Using the previous criteria, duplicated flights are retrieved and compared in order to identify which flight will provide its flight legs for the final merged flight. If the flights are considered as matching, then the OID of the earliest flight is kept. All other matching flights are tagged with this OID. The arrival time selected is the latest time.
.  Update of duplicated flights

Comparisons are made on a set of tagged duplicated flights that should be merged. The first record in the set is replaced with the result of the comparison. The choice of the legs to select is based on the result of the assessment and the number of flight legs for a zone. For example, if the first flight is incomplete for the departure but the flight to compare with is complete then the leg to be selected will be the one from the second flight. If the second flight was also incomplete then the number of legs is counted and the flight with the larger number of legs is kept. The same method is applied to all zones. This approach assures that the best of all trajectory data is retained.

. Copy of flight headers and legs from the temporary table to the definitive table
All flight headers and legs from the temporary flight headers and legs tables are then copied into definitive flight headers and legs tables (Table 30 and Table 31). Flights for which no duplicated flights were identified are saved unchanged in the merge table. 

Table 30: Table FLIGHT.

Col #  Column Name  Data Type  Data Description 
1  OID  NUMBER(15)  Object Identifier for the flight 
2  CALLSIGN  VARCHAR2(15)  Flight’s callsign 
3  DEP_TIME  DATE  Time and date of departure 
4  DEP_AIRPORT  VARCHAR2(5)  Airport of departure 
5  ARR_AIRPORT  VARCHAR2(5)  Airport of arrival 
6  SOURCES  VARCHAR2(20)  The name of the sources this record was imported from (AMOC, ETMS, Back Aviation) 
7  FLUID  VARCHAR2(21)  Flight unique identifier 
8  AIRCRAFT_TYPE  VARCHAR2(15)  Aircraft type 
9  ARR_TIME  DATE  Time and date of arrival 
10  ASSESSMENT  NUMBER  Number (0 to 7) attributed to the trajectory for assessing the quality 

Table 31: Table FLIGHT_LEG.
Col #  Column Name  Data Type  Data Description 
1  OID  NUMBER(15)  Object Identifier for the flight 
2  FLIGHT_OID  NUMBER(15)  Object Identifier for each leg of the flight 
3  CALLSIGN  VARCHAR2(15)  Flight’s callsign 
4  EVENT_TIME  DATE  Time and date of the event 
5  LATITUDE  NUMBER(17,7)  Latitude of the event in decimal degree 
6  LONGITUDE  NUMBER(17,7)  Longitude of the event in decimal degree 
7  GROUND_SPEED  NUMBER(17,7)  Ground speed in knots 
　
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本文鏈接地址：AERO2K Flight Movement Inventory Project Report(27)