  Tachyon inflation is reconsidered by using the recent observational data
obtained from Planck-2013 and BICEP2. The Hamilton-Jacobi formalism is picked
out as a desirable approach in this work, which allows one to easily obtain the
main parameters of the model. The Hubble parameter is supposed as a power-law
and exponential function of the scalar field, and each case is considered
separately. The constraints on the model, which come from observational data,
are explained during the work. The results show a suitable value for the tensor
spectral index and an appropriate form of the potential.
