Fig. 1. Schematic diagram of coverage scenario of UAV base station

Fig. 2. Airborne wireless ultraviolet NLOS scattering communication model

Fig. 3. Coverage model of single UAV

Fig. 4. Optimal distance between UAVs

Fig. 5. UAV coverage process without obstacles

Fig. 6. UAV coverage process with electronic fence

Fig. 7. Relationship between coverage and path loss and UAV height and receiving elevation

Fig. 8. Relationship between coverage and path loss and UAV altitude and launch elevation

Fig. 9. Relationship between coverage and path loss and UAV height and divergence angle

Fig. 10. Relationship between coverage and path loss and UAV height and receiving field angle

Fig. 11. Relationship between UAV number and coverage

Fig. 12. Algorithm comparison