The astronomical lore in Vedic literature provides elements of an absolute chronology in a consistent way.  For what it is worth, this corpus of astronomical indications suggests that the Rg-Veda was completed in the 4th millennium AD, that the core text of the Mahabharata was composed at the end of that millennium, and that the Brahmanas and Sutras are products of the high Harappan period towards the end of the 3rd millennium BC.  This corpus of evidence is hard to reconcile with the AIT, and has been standing as a growing challenge to the AIT defenders for two centuries.