USRP2 synchronization

Hi,

Can anyone give me an idea how to synchronize two USRP2’s using two
GPS
receiver modules, I have one GPS receiver for each USRP2.

I have connected Ref Clock and 1 PPS to the USRP2 from GPS receiver ,
and
similarly for another USRP2.

After the setup, do USRP2 sycnhronize automatically to the given
Reference
clock and PPS ??

If Yes then How do I cross check or verify that they are synchronized ?

Thanks in advance

MADAN