def process_prologue(self):
        """Reprocess prologue to correct types."""

        for key in ['TCurr', 'TCHED', 'TCTRL', 'TLHED', 'TLTRL', 'TIPFS',
                    'TINFS', 'TISPC', 'TIECL', 'TIBBC', 'TISTR', 'TLRAN',
                    'TIIRT', 'TIVIT', 'TCLMT', 'TIONA']:
            try:
                self.prologue[key] = make_sgs_time(self.prologue[key])
            except ValueError:
                self.prologue.pop(key, None)
                logger.debug("Invalid data for %s", key)

        for key in ['SubSatLatitude', "SubSatLongitude", "ReferenceLongitude",
                    "ReferenceDistance", "ReferenceLatitude"]:
            self.prologue[key] = make_gvar_float(self.prologue[key])
Reprocess prologue to correct types.