A method for detecting an obstacle includes the steps of: calculating, for each point of a space around a telemeter, a plurality of corresponding intermediate probabilities of presence, each intermediate probability of presence being associated with a respective orientation of the telemeter among a plurality of predetermined orientations around a current orientation of the telemeter, each orientation being certain; for each point of space, calculating a probability of the presence of an obstacle from each corresponding intermediate probability of presence and from an uncertainty model on the orientation of the telemeter; and generating an alert if the probability of the presence of an obstacle in a predetermined zone with respect to the telemeter is greater than or equal to a predetermined alert threshold.