Several continuous phase modulation (CPM) models along with binary phase shift keying (BPSK) are compared as for the signal delay estimate potential accuracy with multipath propagation, spectral resources being tightly limited. Despite of the effects of the multipath interference, the CPM formats remain always superior to the BPSK format at least by 8–10 dB under the worst conditions despite of the effects of the multipath interference, the CPM formats remain always superior to the BPSK format at least by 8–10 dB under the worst conditions.