The Spectral and Photometric Imaging Receiver (SPIRE) is one of three scientific instruments on the European
Space Agency's (ESA) Herschel Space Observatory (HSO). The medium resolution spectroscopic capabilities of
SPIRE are provided by an imaging Fourier transform spectrometer (IFTS). A software simulator of the SPIRE
IFTS was written to create realistic data products, making use of available qualification and test data. A
graphical user interface (GUI) provides fast and flexible access to the simulation engine. We present the design
and integration of the simulator, as well as results from the simulator predicting the instrument performance
under varying operational conditions.
Imaging Fourier transform spectrometers (IFTS) are becoming the preferred systems for remote sensing spectral imaging applications because of their ability to provide, simultaneously, both high spatial and spectral resolution images of a scene. IFTS can be operated in either step-and-integrate or rapid-scan modes, where it is common practice to sample interferograms at equal optical path difference intervals. The step-and-integrate mode requires a translation stage with fast and precise point-to-point motion and additional external trigger circuitry for the detector focal plane array (FPA), and produces uniformly position-sampled interferograms which can be analyzed using standard FFT routines. In the rapid-scan mode, the translation stage is continuously moving and interferograms are often acquired at the frame-rate of the FPA. Since all translation stages have associated velocity errors, the resulting interferograms are sampled at non-uniform intervals of optical path difference, which requires more sophisticated analysis. This paper discusses the processing pipeline which is being developed for the analysis of the non-uniform rapid-scan data produced by the Herschel/SPIRE IFTS.
The Spectral and Photometric Imaging Receiver (SPIRE) is one of three scientific instruments on ESA's Herschel mission. The spectroscopic capabilities of SPIRE are provided by an imaging Fourier transform spectrometer (IFTS). A software simulator of the IFTS has been constructed to predict the instrument performance under operational conditions. We describe in detail the design and integration of the simulator. Examples of simulated data of astronomical targets are presented.