Submarine position detection method based on extreme points of gravity gradients

A method comprising:

• determining a horizontal position coordinates (X, Y) of a submarine according to a position of a central extreme point and a central position between extreme points of non-diagonal components of a gradient tensor, the coordinates (X, Y) being in a space rectangular coordinate system established using a submarine model,
• wherein the submarine model comprises a hemispherical head (1), a middle cylindrical portion (4), a conical tail (3) and an internal cylindrical pressure-resistant cabin (2), and
• wherein the space rectangular coordinate system is established by taking a centroid of the middle cylindrical portion (4) as a coordinate origin, with a direction pointing to a bow of the submarine model as a forward direction of an X axis, a direction pointing to a port of the submarine model as a forward direction of a Y direction, and a vertical upward direction as a forward direction of a Z axis;
• determining a functional relation between a depth and extreme points of gravity gradient by using the submarine model, the gravity gradient generated by the submarine;
• deducing a depth of the submarine according to the extreme point of gravity gradient, and transferring to a corresponding coordinate system to obtain Z;
• and
• obtaining a position (X, Y, Z) of the submarine based on the coordinates (X, Y) and the depth of the submarine.