Method of using telemetry to detect at least one suspended threadlike object, the object lying in the detection field of a telemeter mounted on board a vehicle

A method of detecting the presence of at least one threadlike object suspended in the detection field of a telemeter on board a vehicle, the method comprising the following steps of mounting the telemeter on board the vehicle, and:

• i) calculating the terrestrial coordinates (x, y, z) of points corresponding to echoes delivered by the telemeter and selecting candidate points from the points;
• ii) searching in a horizontal plane for straight line segments that are close to vertical projections of the candidate points;
• and
• iii) searching in each vertical plane containing a straight line segment found in step ii) for catenary portions that are close to the candidate points;
• wherein in step iii), for each vertical plane under consideration, and for each set of at least four candidate points close to the vertical plane under consideration, using the least squares method to calculate the values of three parameters a, b, and c of a catenary having an equation of the form:
• y=a cos h[(x−b)/a]+c
• the catenary containing the projections on the vertical plane of the points in the set under consideration;
• and
• determining that at least one suspended threadlike object is present as a function of the value of the correlation coefficient associated with the least squares method for all of the sets of at least four candidate points close to the vertical plane under consideration, wherein when the correlation coefficient defined by the least square method is greater than a threshold value, the presently calculated catenary is validated.

A method of detecting the presence of at least one threadlike object suspended in the detection field of a telemeter on board a vehicle, the method comprising the following steps of mounting the telemeter on board the vehicle, and:

• i) calculating the terrestrial coordinates (x, y, z) of points corresponding to echoes delivered by the telemeter and selecting candidate points from the points;
• ii) searching in a horizontal plane for straight line segments that are close to vertical projections of the candidate points;
• and
• iii) searching in each vertical plane containing a straight line segment found in step ii) for catenary portions that are close to the candidate points;
• wherein in step iii), for each vertical plane under consideration, and for each set of at least four candidate points close to the vertical plane under consideration, using the least squares method to calculate the values of three parameters a, b, and c of a catenary having an equation of the form:
• y=a cos h[(x−b)/a]+c
• the catenary containing the projections on the vertical plane of the points in the set under consideration;
• and
• determining that at least one suspended threadlike object is present as a function of the value of the correlation coefficient associated with the least squares method for all of the sets of at least four candidate points close to the vertical plane under consideration, wherein during step i), prior to calculating the terrestrial coordinates of the points corresponding to the echoes delivered by the telemeter, a grid is formed in a horizontal plane in the frame of reference of the telemeter, each mesh of the grid being capable of containing only one point, the candidate points being those that present a height greater than a predetermined altitude and presenting a number of neighbors in the meshes adjacent to their own mesh that is not greater than two.