function ConstantPositionProperty(value, referenceFrame) {
  this._definitionChanged = new Event();
  this._value = Cartesian3.clone(value);
  this._referenceFrame = referenceFrame ?? ReferenceFrame.FIXED;
}
A {@link PositionProperty} whose value does not change in respect to the
{@link ReferenceFrame} in which is it defined.

@alias ConstantPositionProperty
@constructor

@param {Cartesian3} [value] The property value.
@param {ReferenceFrame} [referenceFrame=ReferenceFrame.FIXED] The reference frame in which the position is defined.