Like many of the TimeStampedXXX, a shiftedBy function that shifts the date of the object could be useful to the TimeStampedDouble and TimeStampedDoubleAndDerivative classes.
The typical use case is to shift a whole curve in time in a for loop.
In the case of the TimeStampedDoubleAndDerivative, the derivative can be taken into account to produce a “logical” point, shifted in time, just like what is done in TimeStampedPVCoordinates, where the velocity and acceleration are used to extrapolate the PVA to a nearby time.
The newly added TimeStampedGeodeticPoint already implements it.
I already made an implementation in a separate branch.