Method and system for detecting obstacles with an obstacle sensor for a rotary-wing aircraft

A signaling method for signaling, in an aircraft having at least one rotary wing, obstacles present in a surrounding space situated outside the aircraft,

• wherein the signaling method comprises an initialization comprising an in-flight determination of a mapping reference frame provided with a vertical axis in the terrestrial reference frame, and a series of operating cycles, each operating cycle comprising:
• acquiring, with at least one LiDAR obstacle sensor, positioning data in a reference frame of the obstacle sensor, each positioning data relating to a position of an obstacle point present on an obstacle in the surrounding space in relation to the obstacle sensor;
• constructing, during the flight, a three-dimensional map of the surrounding space, and positioning the aircraft in the map, by applying a simultaneous localization and mapping process based at least on the positioning data, the map being generated in the mapping reference frame;
• and
• displaying, during the flight, on a display of the aircraft, an aircraft symbol showing the aircraft and a two-dimensional representation, restricted to the display, of at least a part of the map containing the aircraft and unlimited in altitude, each point displayed in the representation being associated with a level of risk that varies as a function of a relative altitude between an obstacle of the surrounding space associated with this displayed point and the aircraft, each displayed point of the representation being displayed according to a graphic charter taking the associated level of risk into consideration.