A Time-Domain Keystone Transform Filter

This paper proposes an alternative form of the Keystone Transform (KT), which is known for mitigating range walk in radar returns. While traditionally applied as an interpolation to the cross ambiguity function (CAF), the present work shows that the KT can be implemented prior to, and agnostic of, the cross correlation operation. The new time-domain KT algorithm is derived as a time-variant filter and demonstrated against simulated data. The computational cost, and architectural flexibility offered by the filter, are each examined.