Camera and radar fusion for determining position of projectile in motion

A method of tracking a projectile in motion, the method comprising:

• determining, with at least one processor, a zero radial speed time of the projectile based on radar measurements of the projectile;
• determining, with the at least one processor, a radial speed of the projectile at a particular time based on the radar measurements;
• determining, by the at least one processor, a radial speed slope at the particular time based on the radial speed measurements;
• determining, by the at least one processor, a two-dimensional (2D) image point of the projectile at the particular time, the 2D image point represents the location of the projectile in an image captured by a camera;
• determining a depth scale coefficient at the particular time based on the zero radial speed time, the radial speed, the radial speed slope, the 2D image point, and a homographic transformation;
• and
• determining a position of the projectile in 3D space at the particular time based on a three-dimensional (3D) position of the camera, the depth scale coefficient, the 2D image point and the homographic transformation.