About the Instrument Simulator FllnS

The work presented in this thesis is the first version of the instrument simulator FllnS and, although proved valid for relatively simple simulations, more instrumental effects need to be implemented in order to approach the simulation of the performance of a real spectro-spatial interferometer in space. 

In the MV-map generator module, accounting for the slewing time of the telescopes will be interesting in order to compute the total observation time, as well as fuel calculations. Related to this, the pointing errors of the telescope need to be simulated not only for the different telescope positions, but also the pointing errors during an FTS scan will need to be modelled. To model these some software optimisation is required because this process is computationally heavy. 

The FTS drive is delicate, and the effect of errors in the velocity of the drive is included in FllnS. However other effects like vibrations during the scan, metrology errors, temperature variations, among others must be taken into account because it can affect the readout of the position of the drive, and hence distort the recovered datacube. 

The telescope beam has been modelled in two ways from the Fourier transform of the telescope aperture, and from the Hankel transform of the radial profile of the telescope, both for a uniform illumination. In both cases different illuminations of 

The thermal system (optics modules) in FllnS has been modelled according to the FIRI-CDF Study Report (ESA Concurrent Design Facility 2006). Variations of this optical setup will require to perform some minimal modifications in FllnS. Currently the cold optics emissivities and transmission (and hence reflection) are constant along the band of operation of the instrument. To input transmission profiles from the different optical elements will narrow the gap between an ideal simulator and a much more realistic one. 

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