The asynchronous interference and multi-echo aliasing exist when two secondary surveillance radar(SSR)interrogators trigger a same target transponder.By carrier phase encoding and modulating within the existing SSR pulse using the extended binary phase shift keying(EBPSK),the Cramer-Rao lower bound and maximum likelihood estimation of a single SSR ranging are derived.And the detection performance in multi-echo response aliasing circumstance is analyzed and simulated.It indicates that when two SSR interrogat...