General description
Specifies mission profiles required for the performance evaluation of air vehicles (aircraft, rotorcraft, etc.). The missionDefininitions node is constructed in such a way, that all civil aircraft missions and missions from MIL-STD-3013A can be specified.
>Hierarchical buildup of the mission definition
The mission definition is built-up in a hierarchical way. As the topmost element of the hierarchical mission definition, missions are created within the missions node. Here, one or more segmentBlocks are referenced. These again link to a sequence of segments, making up parts of the missions:
<missions> | containing the <startCondition> and a sequence of <segmentBlockUIDs> |
<segmentBlocks> | grouping multiple
|
<segments> | containing detailed information per segment: EITHER
OR OR |
startConditions, constraints, endConditions and the relationalOperator attribute
the startCondition is provided at the mission node. Each subsequent segmentBlock/segment ends by the provided endCondition.
<startCondition> | start condition of the mission (can be an airfield or mid-air condition) |
<endCondition> | specific end condition for a <segmentBlock> or <segment> (e.g.: an altitude or velocity) |
<constraint> | specific performance settings for a <segmentBlock> or <segment> (e.g.: a cruise Mach number) |
attribute @relationalOperator | Indicate how conditions should be interpreted:
|
Example implementation for a civil transport mission
In the figure above, an example for a civil aircraft transport mission is provided.
The mission starts at a position of 0, 0, 0 with 0 velocity, as provided by the of the <mission> node. Furthermore, the environmental conditions are provided: ISA atmosphere with a <deltaTemperature> of 0 [K]. The mission consists of three <segmentBlocks>: designMission, reserves and endPhase, the last one comprising the landing and taxiIn phase.
<mission uID="exampleMission">
<name>example mission</name>
<description>this is an example mission</description>
<startCondition>
<calibratedAirSpeed>0.0</calibratedAirSpeed>
<positionXYZ>
<x>0.0</x>
<y>0.0</y>
<z>0.0</z>
</positionXYZ>
<environment>
<atmosphericModel>ISA</atmosphericModel>
<deltaTemperature>0.0</deltaTemperature>
</environment>
</startCondition>
<segmentBlockUIDs>
<uID>designMission</uID>
<uID>reserves</uID>
<uID>endPhase</uID>
</segmentBlockUIDs>
</mission> The designMission <segmentBlock> is shown below. It provides a set of five segments, together making up a mission with a range of 1000 [nm] or 1852 [km]. The “cruise” segment is the variable segment, which thereby should have a range of: 1852000 – range(climb) – range(descent), provided the taxiOut and takeOff segments are not providing any range credit. The fuel burned during this <segmentBlock> should be added to the designFuel, the <segmentDirection> is provided for illustration purposes.
<segmentBlocks>
<segmentBlock uID="designMission">
<name>design mission</name>
<description>segment block for the design mission</description>
<segmentBlockConstraints>
<endCondition>
<range relationalOperator="eq">1852000</range>
</endCondition>
</segmentBlockConstraints>
<variableSegments>
<variableSegment>
<segmentUID>cruise</segmentUID>
<variableConditions>range</variableConditions>
</variableSegment>
</variableSegments>
<fuelPlanningType>designFuel</fuelPlanningType>
<segmentDirection>outbound</segmentDirection>
<segmentUIDs>
<uID>taxiOut</uID>
<uID>takeOff</uID>
<uID>climb</uID>
<uID>cruise</uID>
<uID>descent</uID>
</segmentUIDs>
</segmentBlock>
</segmentBlocks> The first and second segment are providing input for the part of the <segmentBlock> that doesn’t need simulation. During the taxiOut phase, 50 [kg] of fuel is burned. The takeOff phase has a duration of 30 [sec].
<segment uID="taxiOut">
<name>taxi out</name>
<description>taxi out segment</description>
<segmentType>massFraction</segmentType>
<fuelMass>50</fuelMass>
</segment>
<segment uID="takeOff">
<name>take off</name>
<description>take off segment</description>
<segmentType>takeOff</segmentType>
<endCondition>
<duration relationalOperator="eq">30</duration>
</endCondition>
</segment> The rest of the segments make-up the flying part of the designMission. The climb phase, ending at an altitude of FL330 or 10058.4 [m], provides a constraint-lapse having discrete steps, typical for transport aircraft (a 250 kt / 300 kt / M 0.78 climb profile). Through the <referenceEndConditionUID> “altClimb”, a link to the altitude <endCondition> of the segment at the basis of this climb profile is provided.
| Altitude from | Altitude to | calibratedAirspeed | machNumber |
| 0.0 [m] | 0.303 * 10058.4 = 3047.7 [m] | ≤ 128.61 [m/s] | ≤ 0.78 [-] |
| 0.303 * 10058.4 = 3047.7 [m] | 10058.4 [m] | ≤ 154.33 [m/s] | ≤ 0.78 [-] |
The cruise phase is not fixed to a certain altitude and has no <endCondition>, since its range is determined by the <segmentBlock> information. The descent phase makes sure the vehicle lands at an altitude of 0 [m]. In this case, since the values are not explicitly provided, it is up to the mission simulation software to determine, when the cruise phase ends and the descent phase starts.
<segment uID="climb">
<name>climb</name>
<description>climb with: speed @ MFCS (set to machNumber le 0.78 [-]), altitude @ FL330</description>
<segmentType>climb</segmentType>
<endCondition>
<positionGeo>
<altitude relationalOperator="ge" uID="altClimb">10058.4</altitude> <!-- FL330 -->
</positionGeo>
</endCondition>
<constraints>
<constraint>
<referenceEndConditionUID>altClimb</referenceEndConditionUID>
<endConditionRatio>0.0;0.303</endConditionRatio> <!-- FL0, FL100 -->
<continuity>discrete</continuity>
<calibratedAirSpeed relationalOperator="le">128.61;154.33</calibratedAirSpeed><!-- 250 [kt], 300 [kt]-->
<machNumber relationalOperator="le">0.78;0.78</machNumber>
<prioritySetting>velocity</prioritySetting>
</constraint>
</constraints>
</segment>
<segment uID="cruise">
<name>cruise</name>
<description>cruise with: speed @ optimum cruise speed, altitude @ optimum cruise altitude</description>
<segmentType>cruise</segmentType>
<endCondition/>
</segment>
<segment uID="descent">
<name>descent to MSL</name>
<description>descent to MSL altitude</description>
<segmentType>descent</segmentType>
<endCondition>
<positionGeo>
<altitude relationalOperator="eq">0</altitude>
</positionGeo>
</endCondition>
</segment> Two more <segmentBlocks> make up the mission. The “reserves” <segmentBlock> provides information for the cruise to alternate airport and loitering phase and the corresponding burnt fuel is considered reserveFuel. The mission ends with a landing and taxiIn phase within the “endPhase” <segmentBlock>, of which the burnt fuel is considered additionalFuel. The following then holds: blockFuel = designFuel + additionalFuel.