Flight direction indication system for an aerial vehicle and method of indicating a flight direction of an aerial vehicle

1. A flight direction indication system for an aerial vehicle having a plurality of rotors, the flight direction indication system comprising:

for each of the plurality of rotors, at least one rotor blade comprising a plurality of light sources arranged along a radial extension of the rotor blade; and

a control unit, coupled to the plurality of light sources of the rotor blades of the plurality of rotors;

wherein the control unit is configured to effect a coordinated control of the plurality of light sources of the rotor blades of the plurality of rotors, with the coordinated control yielding an image or a sequence of images across the plurality of rotors to an observer of the aerial vehicle;

wherein the control unit is configured to control the plurality of light sources of the rotor blades of the plurality of rotors on the basis of a momentary flight direction of the aerial vehicle, with said image or said sequence of images comprising a flight direction indication, indicative of the momentary flight direction of the aerial vehicle;

wherein said image comprises a green sector in a right forward direction with respect to the momentary flight direction of the aerial vehicle, a red sector in a left forward direction with respect to the momentary flight direction of the aerial vehicle, and a white sector in a rearward direction with respect to the momentary flight direction of the aerial vehicle; and

wherein the flight direction system further comprises at least one of a flight direction sensor for detecting the momentary flight direction of the aerial vehicle and a flight direction signal input for receiving a flight direction signal indicative of the momentary flight direction of the aerial vehicle.

2. The flight direction indication system according to claim 1 , wherein the plurality of light sources are arranged along more than 50% of the radial extension of the rotor blade.

3. The flight direction indication system according to claim 1 , wherein the plurality of light sources are arranged along than 70% of the radial extension of the rotor blade.

4. The flight direction indication system according to claim 1 , wherein the plurality of light sources are arranged along between 70% and 90% of the radial extension of the rotor blade.

5. The flight direction indication system according to claim 1 , wherein the plurality of light sources comprise light sources of different colors, in particular light sources of at least three different colors.

6. The flight direction indication system according to claim 1 , wherein the plurality of light sources are a plurality of LEDs.

7. The flight direction indication system according to claim 1 , further comprising:

for each of the plurality of rotors, a blade position sensor for sensing the position of the rotor blade during rotation.

8. The flight direction indication system according to claim 1 , wherein the sensors are Hall sensors or optical sensors.

9. The flight direction indication system according to claim 1 , wherein the control unit is coupled to the plurality of light sources of the rotor blades of the plurality of rotors via at least one wireless transmission link or via a plurality of sliding contacts.

10. The flight direction indication system according to claim 1 , wherein said image comprises at least one arrow, pointing substantially in the momentary flight direction of the aerial vehicle.

11. An aerial vehicle, comprising:

a plurality of rotors; and

a flight direction indication system, comprising:

for each of the plurality of rotors, at least one rotor blade comprising a plurality of light sources arranged along a radial extension of the rotor blade; and

a control unit, coupled to the plurality of light sources of the rotor blades of the plurality of rotors;

wherein the control unit is configured to effect a coordinated control of the plurality of light sources of the rotor blades of the plurality of rotors, with the coordinated control yielding an image or a sequence of images across the plurality of rotors to an observer of the aerial vehicle;

wherein the control unit is configured to control the plurality of light sources of the rotor blades of the plurality of rotors on the basis of a momentary flight direction of the aerial vehicle, with said image or said sequence of images comprising a flight direction indication, indicative of the momentary flight direction of the aerial vehicle;

wherein said image comprises a green sector in a right forward direction with respect to the momentary flight direction of the aerial vehicle, a red sector in a left forward direction with respect to the momentary flight direction of the aerial vehicle, and a white sector in a rearward direction with respect to the momentary flight direction of the aerial vehicle; and

wherein the flight direction system further comprises at least one of a flight direction sensor for detecting the momentary flight direction of the aerial vehicle and a flight direction signal input for receiving a flight direction signal indicative of the momentary flight direction of the aerial vehicle.

12. The aerial vehicle according to claim 11 , wherein the plurality rotors includes between 3 and 10 rotors.

13. The aerial vehicle according to claim 11 , wherein the plurality rotors includes 4 rotors, 8 rotors or between 4 and 8 rotors.

14. The aerial vehicle according to claim 11 , wherein the aerial vehicle is an unmanned aerial vehicle.

15. A method of indicating a momentary flight direction of an aerial vehicle having a plurality of rotors, with each of the plurality of rotors having at least one rotor blade comprising a plurality of light sources arranged along a radial extension of the rotor blade, the method comprising:

at least one of detecting the momentary flight direction of the aerial vehicle with a flight direction sensor and receiving a flight direction signal indicative of the momentary flight direction of the aerial vehicle;

controlling the plurality of light sources of the rotor blades of the plurality of rotors in a coordinated manner, with the coordinated control yielding an image or a sequence of images across the plurality of rotors to an observer of the aerial vehicle; and

controlling the plurality of light sources of the rotor blades of the plurality of rotors on the basis of the momentary flight direction of the aerial vehicle, with said image or said sequence of images comprising a flight direction indication, indicative of the momentary flight direction of the aerial vehicle;

wherein said image comprises a green sector in a right forward direction with respect to the momentary flight direction of the aerial vehicle, a red sector in a left forward direction with respect to the momentary flight direction of the aerial vehicle, and a white sector in a rearward direction with respect to the momentary flight direction of the aerial vehicle.

16. The Method according to claim 15 , wherein the plurality of light sources comprise light sources of at least three different colors.

17. The method according to claim 15 , wherein said image comprises at least one arrow pointing substantially in the momentary flight direction of the aerial vehicle.