NSEU,
Regarding Autobrakes/Antiskid. On the B744, the IRS and main wheel speed transducers (located in the main wheel axles) send speed signals to the BSCU (Brake system control unit) for antiskid/autobrake control.
The wheel speed signal is the PRIMARY signal and the IRS signal is the secondary. For hydroplane and autobraking protection there is, to some degree, cross referencing of speed signals from both the wheel transducers and the IRS by the BSCU.
McHale.