Controlling spacecraft landings with constantly and exponentially decreasing time-to-contact

Two bioinspired landing strategies are studied. Both strategies enforce a constant ventral optic flow with constantly decreasing time-to-contact or exponentially decreasing time-to-contact. Until now these strategies have only been studied assuming the visual quantities to be known, i.e., without sensor noise and delay. In this study, the control laws executing the aforementioned landing strategies are studied both theoretically and empirically, taking into account the actual extraction of the visual cues from images.