**4.3 Heliport tracking**

This experiment was a flight over a heliport located in a park area of the Institute, and the shots were taken from zenithal videos because an artificial vision navigation system was tested to aid the landing. The characteristics of these images

**Figure 8.** *Six rotors "UAV" sequence of the particle estimator.*

**Figure 9.** *Heliport tracking sequence of the particle estimator.*

are that they are interfered by infrared radiation from the ground, and the heliport is not properly marked.

The **Figure 9** shows two sequences of the particle estimator execution, the upper correspond to the startup, and the lower in the middle of the experiment. From left to right and from top to bottom, the first frame corresponds to the initialization of the estimator, the particles are distributed over the whole image and the most probable particle in the center of the screen. In the second frame after 0.04 seconds (frame rate) only two particles have probability higher than the threshold, and it can be seen how the most probable particle reached the target. After that the estimator is locked, and remains in sequence of tracking.
