A320 Captain reported failure of multiple navigation systems during climb resulted in the flight crew using raw data. Flight crew returned to the departure airport.

Narrative

During climb out between FL270- FL280 received ECAM - NAV LS TUNING DISAGREE. Captain was pilot flying (PF) and continued to fly and called for ECAM actions. First Officer (FO) ( pilot monitoring (PM) ) acknowledged ECAM and applied QRH procedures for this non-normal and the fault was cleared. After a few minutes we received the same ECAM - NAV LS TUNING DISAGREE followed by Autopilot; Auto throttles and Flight Director (FD) 1&2 disconnected. Also MAP DISPLAY NOT AVAILABLE and GPS PRIMARY LOST message on Navigation display ( ND ). I ( Captain ) continued to fly and called for ECAM actions. FO ran ECAM and proceeded to QRH. We advised ATC and requested radar vectors and headings to avoid weather North of our flight path. When QRH was completed we made the decision to return to ZZZ and [requested priority handling]. Control was then transferred from Captain to FO. We assessed our non normal. I ( Captain ) contacted Dispatch and Maintenance Control via SATCOM. Maintenance asked if we performed QRH for dual FMGC failure. I advised we had but I would do it again. After reviewing QRH with no success we made the decision to use Raw Data as primary navigation aid and made ATC aware of the aircraft malfunctions. I then briefed the flight attendants. PA was made for the passengers about our intention to return to ZZZ due to aircraft maintenance issues. We calculated approach speed using QRH and flight manual and completed our checklist. Requested radar vectors from ATC for a visual approach and the landing was uneventful. When clear of the runway advised flight attendants to remain seated and taxied to the gate. Passengers deplaned and made logbook entries. END.