Method for locating an aircraft in flight

Method for locating an aircraft in-flight, the aircraft overflying a zone of space comprising on the ground, the overflown zone being a landing site of the aircraft, characteristic elements arranged in at least one row, the characteristic elements being characteristic elements of the landing site, the method being implemented by a locating device borne by the aircraft, the locating device comprising a first locating unit and a second locating unit, the first locating unit comprising at least one sensor selected from an inertial sensor and a radio-navigation sensor, the second locating unit comprising a radar, the method comprising:

• a first phase of determining a position of the aircraft, called first position, by the first locating unit as a function of a signal supplied by the at least one sensor;
• simultaneously with the first phase of determining, a second phase of determining a position of the aircraft, called second position, by the second locating unit, the second phase of determining comprising:
• detecting, by the radar, the characteristic elements of the zone overflown, each detection of the characteristic elements being associated with coordinates;
• determining, according to the coordinates of the detected characteristic elements:
• distance of an orthogonal projection on a straight line passing through the at least one of the rows of elements of the horizontal projection of the radar, called the first distance, the horizontal projection of the radar being the orthogonal projection of the position of the radar on the ground;
• and
• distance of the orthogonal projection on a line perpendicular to the at least one of the rows of elements, called the second distance;
• and
• determining the second position according to the determined first and second distances;
• and
• a phase of comparing data associated with the first position and data associated with the second position after which the first position is either validated or invalidated,
• wherein the landing site comprises a runway having a longitudinal axis equidistant from the longitudinal edges of the runway, called runway centerline, the characteristic elements being distributed over the runway in at least two longitudinal rows and at least one transverse row, the longitudinal rows being substantially parallel to the runway centerline, two of the longitudinal rows being each arranged along a distinct longitudinal edge of the runway, the at least one transverse row being substantially perpendicular to the runway centerline, the last one of the at least one transverse row along the direction of aircraft landing on the runway being called the runway threshold, the first distance being the distance from the orthogonal projection on the runway centerline of the horizontal projection of the radar, called axial offset, the second distance being the distance from the orthogonal projection on the straight line passing through the runway threshold of the horizontal projection of the radar, called the distance to the runway threshold.