33.6. Platform Motion
The platform motion model simulates an imaging system platform that can move as a function of time. The <platformmotion> element contains description for the time-based position and orientation. The following diagram shows the content of the element:
33.6.1. Method
The <method> element describes the method in which the data was created (hand-generated or imported from other sources). In this example, we used a free-style "raw" method to create the data:
<method type="raw" />
33.6.2. Uncertainty
The optional <uncertainty> element contains description for uncertainty associated with each location and orientation parameter. At this time, the model only supports a zero meaned, normal distributed noise about the supplied data. For each parameter, the user can supply the variance for that normal distribution. In the future time, a mean value may be added that would model an offset in the measured values:
<uncertainty enabled="0" >
<xlocation type="normal" >
<variance>0.0000000000</variance>
</xlocation>
<ylocation type="normal" >
<variance>0.0000000000</variance>
</ylocation>
<zlocation type="normal" >
<variance>0.0000000000</variance>
</zlocation>
</uncertainty>
33.6.3. Data
The <data> element contains a series of <entry> elements that describe the platform location and orientation at specific sets of time. The <data> tag includes the rotationorder attribute which is assigned a string that indicates the order of the axis rotations. The spatialunits attribute is used to define the units of all the location values as it currently supports only metric units. The angularunits attribute is used to define the units of all rotational angles as it currently only supports radians.
The <entry> element defines the description for the time-based location and orientation. The <datetime> element supports both absolute and relative times. The X, Y and Z locations are in scene units and the X, Y and Z rotations are assumed to be absolute and in radians in this sample:
<data rotationorder="zyx" angletype="absolute" angularunits="radians" spatialunits="meters" >
<entry>
<datetime type="absolute" >1996-06-24T12:30:00.0000-05:00</datetime>
<xlocation>243.8400000000</xlocation>
<ylocation>243.8400000000</ylocation>
<zlocation>304.8000000000</zlocation>
<xrotation>0.0000000000</xrotation>
<yrotation>0.0000000000</yrotation>
<zrotation>0.0000000000</zrotation>
</entry>
</data>