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This program generates GTIs for ISGRI and PICsIT. The GTIs depend on the presence of the science data. A time is defined as bad if a science packet of the instrument is missing. The expected science packets depend on the actual mode of the instrument. This is taken into account while the GTI is being created. The program does not distinguish between a pointing, a slew and an engineering window. The time is also set to be "bad" if there are scientific data that do not agree with the reported mode of the instrument.

Time is also defined bad if the telemetry indicates that there was an interruption of the on-board processing due to a telemetry saturation. In normal operation this case is rather seldom.

The final GTI is written into the IBIS index group and has the name ``ISGRI_DATA_GAPS'' and ``PICSIT_DATA_GAPS'' for ISGRI and PICsIT correspondingly.