Air carrier pilot flying reported experiencing GPS jamming in the area that caused the GPS to malfunction and led to the flight crew needing to hand-fly the approach. The reporter stated there were no NOTAMs.

Narrative

Approximately 50 miles west of CIKAN GPS 2 started to falter and lose integrity dropping offline. Went to QRH and completed procedure which was the message presented on ECAM. We reached out to Dispatch to inform them of situation and their response was to also run [another] procedure; which we did and completed this as well. While completing the QRH procedures we advised ATC of the situation. When advised of this we were told; Yeah expect that until almost TUS." We continued to actively monitor FMGC integrity and position to maintain accurate navigation. When handed off to TUS we advised them of the situation as well and they advised it should come back as we get closer. We continued to monitor the GPS and saw that GPS 1 was coming back; it managed to obtain 10 satellite signals before quickly dropping back down and losing integrity again. It never recovered a signal strong enough to become reliable. At this point we requested to VOR 30 which we were vectored for as we had briefed previously as a backup in case of the GPS not coming back. After being cleared for the approach it was armed and did not acquire the approach accurately to which we then continued the approach hand-flown / raw data. The box had become what we think was lost and contributed to this issue of the approach. Cause: GPS jamming that was not NOTAM'd out in the area."