  By taking into account the contamination of foreground radiations, we employ
the Fisher matrix to forecast the future sensitivity on the tilt of power
spectrum of primordial tensor perturbations for several ground-based (AdvACT,
CLASS, Keck/BICEP3, Simons Array, SPT-3G), balloon-borne (EBEX, Spider) and
satellite (CMBPol, COrE, LiteBIRD) experiments of B-mode polarizations. For the
fiducial model $n_t=0$, our results show that the satellite experiments give
good sensitivity on the tensor tilt $n_t$ to the level
$\sigma_{n_t}\lesssim0.1$ for $r\gtrsim2\times10^{-3}$, while the ground-based
and balloon-borne experiments give worse sensitivity. By considering the
BICEP2/Keck Array and Planck (BKP) constraint on the tensor-to-scalar ratio
$r$, we see that it is impossible for these experiments to test the consistency
relation $n_t=-r/8$ in the canonical single-field slow-roll inflation models.
