Ionospheric sounding using coded pulse signals

At present, ionospheri c so unders rely on t he transmission of hi gh peak-pulse-power to provide for t he detection of rece ived echoes . To allow for t he detection of signals wit h pOOl' signal-to-noise ra t ios, t he transmitted energy must be in creased . It can be ass umed that significa nt increases a re not likel y to be obtained t hrou g h increases in t he peak t ransmi tted power. Also, an y increase in t ra nsmitted e nergy ac hi eved t hrough a simple in crease in pulse duration is acco mpa nied by a corrcsponding loss of ra nge resolu tion . Pulse comprcssion signals provide a n increase in t ra n smi tte r! ene rgy, wi t hout an increase of peak power, a nd "'it hou t a loss of range resolution .