IRS inflight alignment??

[Mork]

It was my understanding that IRS/INS's are to be aligned on the ground with the aircraft parked. I was told these days that IRS's are capable of inflight alignment with the use of GPS, and useable for navigational purposes after.

I know that the IRS's can be realgined in flight to recover the attitude indicator but without navigational capabilities.

Can anyone help me out and explain if newer aircraft have this capability??

Thanks in advance,

Mork