Fig. 1. Landing landmarks

Fig. 2. Image processing process

Fig. 3. Image coordinate system straight line

Fig. 4. Coordinate system of camera imaging projection

Fig. 5. Reference direction line and coordinate system quadrant

Fig. 6. Visual assisted flight control system

Fig. 7. Horizontal position control law

Fig. 8. Altitude control law

Fig. 9. Effect of square root controller

Fig. 10. Attitude control law

Fig. 11. Attitude control mechanism

Fig. 12. Simulation curves of north position and desired position

Fig. 13. Simulation curves of east position and desired position

Fig. 14. Intermeshing-rotor unmanned helicopter

Fig. 15. OpenMV4 H7 Plus camera

Fig. 16. Roll angle curve

Fig. 17. Pitch angle curve

Fig. 18. Yaw angle curve

Fig. 19. North position and desired position curves

Fig. 20. East position and desired position curves