Abstract: A seeker circuit for homing missile guidance comprising a velocity memory loop and an acceleration memory loop. During the presence of an adequate target data signal, the guidance computer uses a command line-of-sight rate based on velocity components of the actual line-of-sight computed by the velocity memory loop. But, during the absence of an adequate target data signal, estimated line-of-sight rate components of the last actual line-of-sight rate computed by the acceleration memory loop are input to the guidance computer. Further, when the target data signal is fading in and out, a stabilizing means effectively stabilizes both loops.