System for determining the position and roll angle of a moving body

A system for determining the roll angle (.phi.), as well as the position with respect to a reference axis (OX), of a moving body (2) having a longitudinal axis (L--L), said system (1) including a stationary optical detector (3) capable of taking a picture (PI) of the area around said reference axis (OX) in which said moving body (2) is likely to move, which includes:

• three optical elements (8, 9, 10) mounted on said moving body (2) and capable of generating light flashes (7) in the direction of said optical detector (3), a first and a second of said optical elements (8, 9), forming a baseline (LB), being mounted so as to be diametrically opposed with respect to said longitudinal axis (L--L) and the third optical element (10) being arranged on a line (PE) at least substantially perpendicular to this baseline (LB) passing through said longitudinal axis;
• and
• a computer (4) linked to said optical detector (3) and capable of determining the position and roll angle (.phi.) of said moving body (2) from the position of said optical elements (8, 9, 10) in a picture (PI) taken by said optical detector (3) which detects said light flashes (7), said roll angle (4) corresponding to the angle between said baseline (LB) and one axis (OY) of a defined reference-axis system (OYZ), the ambiguity of 180.degree. in said roll angle being removed by the position of said third optical element (10), and the position of said moving body (2) with respect to said reference axis (OX) being obtained from the projection of the position of said third optical element (10) on said baseline (LB).