A method for securing a ground speed used for guiding landing of an aircraft by determining a ground speed of the aircraft and determining a landing guidance instruction based on the determined ground speed. Next, estimate the vertical speed of the aircraft and limit, during guidance along a glide path having a descent angle, the determined ground speed as a function of the estimated vertical speed. The guidance instruction is based on the limited ground speed. Further, measure the height of the aircraft and compare it with a threshold height. If the measured height is greater than the threshold height, limit the ground speed as a function of acceleration measurements. If the measured height is below the threshold height, limiting the ground speed as a function of the estimated vertical speed and as a function of acceleration measurements of the aircraft taken once threshold height has been crossed.