U.S. patent application number 16/712457 was filed with the patent office on 2021-02-18 for method of emitting an anti-collision light output from an unmanned aerial vehicle, anti-collision light for an unmanned aerial vehicle, and unmanned aerial vehicle comprising the same.
The applicant listed for this patent is Goodrich Lighting Systems GmbH. Invention is credited to Andre HESSLING-VON HEIMENDAHL, Anil Kumar JHA.
Application Number | 20210047051 16/712457 |
Document ID | / |
Family ID | 1000005370927 |
Filed Date | 2021-02-18 |
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United States Patent
Application |
20210047051 |
Kind Code |
A1 |
HESSLING-VON HEIMENDAHL; Andre ;
et al. |
February 18, 2021 |
METHOD OF EMITTING AN ANTI-COLLISION LIGHT OUTPUT FROM AN UNMANNED
AERIAL VEHICLE, ANTI-COLLISION LIGHT FOR AN UNMANNED AERIAL
VEHICLE, AND UNMANNED AERIAL VEHICLE COMPRISING THE SAME
Abstract
A method of emitting an anti-collision light output from an
unmanned aerial vehicle includes emitting a plurality of light
flashes of different colors within a flash duration interval, with
the flash duration interval being at most 0.2 s; wherein the
plurality of light flashes within the flash duration interval
comprise at least one blue light flash and at least one yellow
light flash or wherein the plurality of light flashes within the
flash duration interval comprise at least one cyan light flash, at
least one magenta light flash, and at least one yellow light
flash.
Inventors: |
HESSLING-VON HEIMENDAHL; Andre;
(Koblenz, DE) ; JHA; Anil Kumar; (Lippstadt,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Goodrich Lighting Systems GmbH |
Lippstadt |
|
DE |
|
|
Family ID: |
1000005370927 |
Appl. No.: |
16/712457 |
Filed: |
December 12, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H05B 47/16 20200101;
B64D 47/06 20130101; B64D 2203/00 20130101; B64C 2201/027 20130101;
H05B 45/20 20200101; B64C 39/024 20130101 |
International
Class: |
B64D 47/06 20060101
B64D047/06; B64C 39/02 20060101 B64C039/02; H05B 45/20 20060101
H05B045/20; H05B 47/16 20060101 H05B047/16 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 15, 2019 |
EP |
19191996.8 |
Claims
1. A method of emitting an anti-collision light output from an
unmanned aerial vehicle, comprising: emitting a plurality of light
flashes of different colors within a flash duration interval, with
the flash duration interval being at most 0.2 s; wherein the
plurality of light flashes within the flash duration interval
comprise at least one blue light flash and at least one yellow
light flash.
2. The method according to claim 1, wherein the plurality of light
flashes within the flash duration interval comprise exactly one
blue light flash and exactly one yellow light flash.
3. The method according claim 1, wherein each of the plurality of
light flashes within the flash duration interval is at least 20
ms.
4. The method according claim 1, wherein the plurality of light
flashes within the flash duration interval are of substantially
equal length.
5. The method according to claim 1, further comprising: repeating
the step of emitting a plurality of light flashes of different
colors within a flash duration interval.
6. The method according claim 5, wherein the step of emitting a
plurality of light flashes of different colors within a flash
duration interval is repeated between 40 times and 100 times per
minute.
7. The method according claim 1, further comprising: emitting white
light flashes, in case one or more human passengers are aboard the
unmanned aerial vehicle.
8. A method of emitting an anti-collision light output from an
unmanned aerial vehicle, comprising: emitting a plurality of light
flashes of different colors within a flash duration interval, with
the flash duration interval being at most 0.2 s; wherein the
plurality of light flashes within the flash duration interval
comprise at least one cyan light flash, at least one magenta light
flash, and at least one yellow light flash.
9. The method according to claim 8, wherein the plurality of light
flashes within the flash duration interval comprise exactly one
cyan light flash, exactly one magenta light flash, and exactly one
yellow light flash.
10. The method according to claim 8, wherein each of the plurality
of light flashes within the flash duration interval is at least 20
ms.
11. The method according to claim 8, wherein the plurality of light
flashes within the flash duration interval are of substantially
equal length.
12. The method according to claim 8, further comprising: repeating
the step of emitting a plurality of light flashes of different
colors within a flash duration interval.
13. Method according to claim 12, wherein the step of emitting a
plurality of light flashes of different colors within a flash
duration interval is repeated between 40 times and 100 times per
minute.
14. The method according to claim 8, further comprising: emitting
white light flashes, in case one or more human passengers are
aboard the unmanned aerial vehicle.
15. An anti-collision light for an unmanned aerial vehicle,
comprising: a plurality of light sources of different colors; and a
control unit coupled to the plurality of light sources, wherein the
control unit is configured to control the plurality of light
sources to emit a plurality of light flashes of different colors
within a flash duration interval of at most 0.2 s, and wherein the
control unit is configured to control the plurality of light
sources to emit at least one blue light flash and at least one
yellow light flash within a flash duration interval or wherein the
control unit is configured to control the plurality of light
sources to emit at least one cyan light flash, at least one magenta
light flash, and at least one yellow light flash within a flash
duration interval.
16. The Anti-collision light according to claim 15, wherein the
plurality of light sources comprise a blue light source and a
yellow light source, or wherein the plurality of light sources
comprise a cyan light source, a blue light source, a red light
source, and a yellow light source.
17. An anti-collision light according to claim 15, wherein the
plurality of light sources are a plurality of LEDs.
18. An unmanned aerial vehicle comprising at least one
anti-collision light in accordance with claim 15, the at least one
anti-collision light anti-collision light being mounted to a
vehicle body of the unmanned aerial vehicle.
19. The unmanned aerial vehicle according to claim 18, wherein the
at least one anti collision light includes an upper anti-collision
light arranged on an upper portion of the unmanned aerial vehicle
and a lower anti-collision light arranged on a lower portion of the
unmanned aerial vehicle.
20. The unmanned aerial vehicle according to claim 18, wherein the
at least one of the at least one anti-collision lights has at least
the following intensities: 400 cd in a first angular range between
0.degree. and 5.degree. with respect to a horizontal plane through
the unmanned aerial vehicle, 240 cd in a second angular range
between 5.degree. and 10.degree. with respect to the horizontal
plane, 80 cd in a third angular range between 10.degree. and
20.degree. with respect to the horizontal plane, 40 cd in a fourth
angular range between 20.degree. and 30.degree. with respect to the
horizontal plane, and 20 cd in a fifth angular range between
30.degree. and 75.degree. with respect to the horizontal plane.
Description
FOREIGN PRIORITY
[0001] This application claims priority to European Patent
Application No. 19191996.8 filed Aug. 15, 2019, the entire contents
of which is incorporated herein by reference.
BACKGROUND
[0002] The present invention is in the field of unmanned aerial
vehicles (UAVs). In particular, the present invention is in the
field of lighting systems for unmanned aerial vehicles.
BRIEF DESCRIPTION
[0003] Recently, the use of unmanned aerial vehicles/drones has
increased significantly. Advances in the control and coordination
of multiple rotors have made multicopters, in particular unmanned
aerial vehicles (UAVs) of this kind, significantly more accessible
and more reliable. A particularly popular kind of an unmanned
aerial vehicle of the multicopter type is a quadrocopter. Various
types of unmanned aerial vehicles have been developed, e.g. for
recreational purposes, for carrying cameras, etc. Multicopters are
further envisioned for the delivery of goods, for other kinds of
courier services, and even for transporting people. With the
envisioned increase in unmanned aerial vehicle traffic, flight
safety is likely to become an increasing concern.
[0004] Accordingly, it would be beneficial to provide a method and
a system for increasing the flight safety of unmanned aerial
vehicles.
SUMMARY
[0005] Exemplary embodiments of the invention include a method of
emitting an anti-collision light output from an unmanned aerial
vehicle, comprising: emitting a plurality of light flashes of
different colors within a flash duration interval, with the flash
duration interval being at most 0.2 s; wherein the plurality of
light flashes within the flash duration interval comprise at least
one blue light flash and at least one yellow light flash.
[0006] Exemplary embodiments of the invention allow for providing
an effective anti-collision warning signal, while allowing for a
clear distinction between unmanned aerial vehicles and traditional,
manned aerial vehicles and allowing for the anti-collision light
output to be in conformity with existing anti-collision lighting
standards and/or practices. The provision of blue and yellow light
flashes allows for an effective distinction with respect to
traditional, manned aerial vehicles, such as passenger aircraft,
because traditional manned aerial vehicles generally only emit
white light flashes, red light flashes, and white, red, and green
continuous light outputs during flight. The emission of blue and
yellow light flashes may be an effective signal to observers on the
ground and/or observers in other aerial vehicles that the vehicle
in question is an unmanned aerial vehicle. Also, blue and yellow
light flashes may be suitable for drawing a high degree of
attention to the unmanned aerial vehicle, thus providing an
effective anti-collision warning signal.
[0007] The at least one blue light flash and the at least one
yellow light flash are provided in a flash duration interval of at
most 0.2 s. By being constrained to a total duration of at most 0.2
s, the at least one blue light flash and the at least one yellow
light flash may be counted as a single light flash in accordance
with particular aviation practices. Via color adding, the at least
one blue light flash and the at least one yellow light flash may
add up to yield a white color. While being perceived as blue and
yellow light flashes by an observer, the blue and yellow light
flashes may count as a single white light flash for aviation
standards and/or practices. In this way, the anti-collision light
output may be compliant with existing aviation standards and/or
practices. Compliance with existing standards and/or practices may
be achieved at the same time as providing for a clear distinction
between unmanned aerial vehicles and traditional, manned aerial
vehicles.
[0008] The method comprises emitting a plurality of light flashes
of different colors within the flash duration interval. The at
least one blue light flash and the at least one yellow light flash
are emitted as subsequent light flashes. In other words, a sequence
of blue and yellow light flashes is emitted during the flash
duration interval. While a slight overlap between the blue and
yellow light flashes may be allowed, significant portions of the
blue and yellow light flashes do not have an overlap. In a
particular embodiment, the blue and yellow light flashes do not
overlap in time.
[0009] The plurality of light flashes within the flash duration
interval comprise at least one blue light flash and at least one
yellow light flash. The terms blue light flash and yellow light
flash refer to bursts of light emission that are perceived as
blueish/yellowish by a human observer. All color shades of blue and
yellow, whose addition yields a color in the aviation white range,
as defined by Federal Aviation Regulations (FAR) section 25.1397
(c) and/or as defined by SAE AS 8017-D, are encompassed by the
terms blue light flash and yellow light flash.
[0010] The term unmanned aerial vehicle (UAV) encompasses all
aerial vehicles that are capable and allowed to fly without a pilot
on board. While the unmanned operation is the intended operation
and the standard operation, the term unmanned aerial vehicle does
not exclude the aerial vehicle to be designed to transport
passengers at selected times. In particular, the unmanned aerial
vehicle may be a so-called air taxi that is capable of transporting
passengers, but that is unmanned in between instances of passenger
transport.
[0011] The unmanned aerial vehicle may be a multicopter. In
particular, the unmanned aerial vehicle may have a vehicle body and
a plurality of rotors supported by the vehicle body. The unmanned
aerial vehicle may comprise between 3 and 10 rotors, in particular
between 4 and 8 rotors, further in particular 4 rotors or 8 rotors.
The latter numbers of rotors refer to the aerial vehicle being a
quadrocopter or an octocopter.
[0012] According to a further embodiment, the plurality of light
flashes within the flash duration interval comprise exactly one
blue light flash and exactly one yellow light flash. In this way,
the flash duration interval may be split up between two light
flashes, which in turn allows for the light flashes to be
particularly well discernable by an observer. Also, observing two
light flashes in a flash duration interval of at most 0.2 s may
allow for a more pleasant perception by the user than seeing a
higher number of light flashes in such a short time interval.
[0013] Exemplary embodiments of the invention further include a
method of emitting an anti-collision light output from an unmanned
aerial vehicle, comprising emitting a plurality of light flashes of
different colors within a flash duration interval, with the flash
duration interval being at most 0.2 s; wherein the plurality of
light flashes within the flash duration interval comprise at least
one cyan light flash, at least one magenta light flash, and at
least one yellow light flash. The considerations laid out above
with respect to emitting at least one blue light flash and at least
one yellow light flash within the flash duration interval apply to
the emission of at least one cyan light flash, at least one magenta
light flash, and at least one yellow light flash in an analogous
manner. Emitting cyan, magenta, and yellow light flashes is an
alternative solution to emitting blue and yellow light flashes.
[0014] Via color adding, the at least one cyan light flash, the at
least one magenta light flash, and the at least one yellow light
flash may add up to yield a white color. While being perceived as
cyan, magenta, and yellow light flashes by an observer, the cyan,
magenta, and yellow light flashes may count as a single white light
flash for aviation standards and/or practices.
[0015] The plurality of light flashes within the flash duration
interval comprise at least one cyan light flash, at least one
magenta light flash, and at least one yellow light flash. The terms
cyan light flash, magenta light flash, and yellow light flash refer
to bursts of light emission that are perceived as a mixture of blue
and green/as a mixture of blue and red/as yellowish by a human
observer. All color shades of cyan, magenta, and yellow, whose
addition yields a color in the aviation white range, as defined by
Federal Aviation Regulations (FAR) section 25.1397 (c) and/or as
defined by SAE AS 8017-D, are encompassed by the terms cyan light
flash, magenta light flash, and yellow light flash.
[0016] According to a further embodiment, the plurality of light
flashes within the flash duration interval comprise exactly one
cyan light flash, exactly one magenta light flash, and exactly one
yellow light flash. In this way, the flash duration interval may be
split up between three light flashes, which in turn allows for the
light flashes to be particularly well discernable by an observer.
Also, observing three light flashes in a flash duration interval of
at most 0.2 s may allow for a more pleasant perception by the user
than seeing a higher number of light flashes in such a short time
interval.
[0017] According to a further embodiment, each of the plurality of
the light flashes within the flash duration interval is at least 20
ms, in particular at least 50 ms. In other words, each of the
plurality of light flashes has an individual duration of at least
20 ms, in particular of at least 50 ms. With the individual light
flashes of different colors being at least 20 ms in duration, they
are clearly discernable as individual flashes by a human observer.
With the individual flashes of different colors having a duration
of at least 50 ms, the light flashes of different colors are even
more clearly discernable as individual light flashes by the
observer and may also be more pleasant to the observer's eye. In
this way, a good compromise between reliable signalling and a
non-disruptive perception on the part of the observer may be
achieved.
[0018] According to a further embodiment, each of the plurality of
light flashes within the flash duration interval is at most 100 ms,
in particular at most 70 ms. In other words, each of the plurality
of light flashes may have an individual duration of at most 100 ms,
in particular of at most 70 ms.
[0019] According to a further embodiment, the plurality of light
flashes within the flash duration interval are of substantially
equal length. In this way, the two/three colors within the flash
duration interval are perceived as having equal importance. This in
turn may allow for an intuitive and widely accepted two-color or
three-color anti-collision warning signal.
[0020] According to a further embodiment, the method comprises
repeating the step of emitting a plurality of light flashes of
different colors within a flash duration interval. In other words,
the method may be carried out over a plurality of flash duration
intervals, with a plurality of light flashes of different colors
being emitted in each of the flash duration intervals,
respectively. The flash duration intervals may be separated by time
periods of no or substantially no light emission. The time periods
of separation may be at least 0.2 s in duration. For example, the
time periods of separation may be between 0.4 s and 1.5 s in
duration.
[0021] In a particular embodiment, the step of emitting a plurality
of light flashes of different colors within a flash duration
interval may be repeated as long as the unmanned aerial vehicle is
in the air. In this way, a continuous anti-collision warning signal
may be output to the observers of the unmanned aerial vehicle, such
as to persons on the ground and/or pilots of other aerial
vehicles.
[0022] According to a further embodiment, the step of emitting a
plurality of light flashes of different colors within a flash
duration interval is repeated between 40 times and 100 times per
minute. In this way, the anti-collision light output may be in
compliance with Federal Aviation Regulations (FAR) section 25.1401
(c) in terms of the number of flashes. In this context, it is
pointed out again that the plurality of light flashes of different
colors within the flash duration interval of at most 0.2 s may be
counted as one flash for the purpose of FAR compliance.
[0023] According to a further embodiment, the method comprises
emitting white light flashes, in case one or more human passengers
are aboard the unmanned aerial vehicle. The white light flashes are
emitted instead of the light flashes of different colors, as
described above. In other words, when white light flashes are
emitted, above described light flashes of different colors are no
longer emitted. In this way, the method may adapt the
anti-collision warning signal, depending on whether the unmanned
aerial vehicle is in a regular unmanned operation mode or whether
the unmanned aerial vehicle is temporarily transporting passengers,
before going back to an unmanned operation. In this way, the method
may adapt the anti-collision warning signal to the current
operating mode of an air taxi or similar aerial vehicle. The
emission of white light flashes is in accordance with traditional
anti-collision light outputs, as for example employed by
traditional passenger aircraft.
[0024] Further exemplary embodiments of the invention include an
anti-collision light for an unmanned aerial vehicle, comprising a
plurality of light sources of different colors; and a control unit
coupled to the plurality of light sources, wherein the control unit
is configured to control the plurality of light sources to emit a
plurality of light flashes of different colors within a flash
duration interval of at most 0.2 s, and wherein the control unit is
configured to control the plurality of light sources to emit at
least one blue light flash and at least one yellow light flash
within a flash duration interval and/or wherein the control unit is
configured to control the plurality of light sources to emit at
least one cyan light flash, at least one magenta light flash, and
at least one yellow light flash within a flash duration interval.
The additional features, modifications and effects, as described
above with respect to the method of emitting an anti-collision
light output from an unmanned aerial vehicle, apply to the
anti-collision light for an unmanned aerial vehicle in an analogous
manner.
[0025] According to a further embodiment, the plurality of light
sources comprise a blue light source and a yellow light source,
and/or the plurality of light sources comprise a cyan light source,
a blue light source, a red light source, and a yellow light source.
In this way, the blue, yellow, and cyan light flashes may be
conveniently provided via switching the respective dedicated light
sources on/off. Also, the magenta light flashes may be conveniently
generated by switching the blue and red light sources
simultaneously on/off. It is also possible that the plurality of
light sources comprise a red light source, a green light source and
a blue light source. Via color mixing of red, green, and blue
light, light flashes of blue, yellow, cyan, and magenta colors may
also be achieved.
[0026] According to a further embodiment, the plurality of light
sources comprise a white light source. The white light source may
be provided in addition to the colored light sources. The provision
of a white light source allows for a convenient way of emitting
white light flashes, which may be desired for indicating a
temporary transport of human passengers, as discussed above.
[0027] According to a further embodiment, the plurality of light
sources are a plurality of LEDs. With LEDs being small light
sources and having comparably low power demands, a particularly
compact implementation of the anti-collision light may be achieved.
This may be particularly desireable in the limited space of an
unmanned aerial vehicle. Also, LEDs are highly reliable and have
quick response times, when being switched on/off by the control
unit for producing the plurality of light flashes of different
colors.
[0028] Exemplary embodiments of the invention further include an
unmanned aerial vehicle comprising at least one anti-collision
light, as described in any of the embodiments above. The additional
features, modifications and effects, as described above with
respect to the method of emitting an anti-collision light output
from an unmanned aerial vehicle and with respect to an
anti-collision light for an unmanned aerial vehicle, apply to the
unmanned aerial vehicle in an analogous manner.
[0029] According to a further embodiment, the unmanned aerial
vehicle is of a multi-copter type. In particular, the unmanned
aerial vehicle may have a vehicle body and a plurality of rotors
supported by the vehicle body.
[0030] According to a further embodiment, the unmanned aerial
vehicle comprises an upper anti-collision light, as described in
any of the embodiments above, arranged on an upper portion of the
unmanned aerial vehicle. In this way, the upper anti-collision
light is well-positioned to provide an anti-collision light output
in the upper hemisphere above the horizontal plane of the unmanned
aerial vehicle. In a particular embodiment, the upper
anti-collision light is arranged on an upper portion of a vehicle
body of the unmanned aerial vehicle.
[0031] According to a further embodiment, the unmanned aerial
vehicle comprises a lower anti-collision light, as described in any
of the embodiments above, arranged on a lower portion of the
unmanned aerial vehicle. In this way, the lower anti-collision
light is well-positioned to provide an anti-collision light output
in the lower hemisphere below the horizontal plane of the unmanned
aerial vehicle. In a particular embodiment, the lower
anti-collision light is arranged on an lower portion of a vehicle
body of the unmanned aerial vehicle.
[0032] According to a further embodiment, the upper anti-collision
light and/or the lower anti-collision light in operation provide an
anti-collision light output having at least the following light
intensities: 400 cd in a first angular range between 0.degree. and
5.degree. with respect to a horizontal plane through the unmanned
aerial vehicle; 240 cd in a second angular range between 5.degree.
and 10.degree. with respect to the horizontal plane; 80 cd in a
third angular range between 10.degree. and 20.degree. with respect
to the horizontal plane; 40 cd in a fourth angular range between
20.degree. and 30.degree. with respect to the horizontal plane; and
20 cd in a fifth angular range between 30.degree. and 75.degree.
with respect to the horizontal plane. In this way, the light
intensities of the upper anti-collision light and/or the lower
anti-collision light may satisfy the minimum requirements, as laid
out in Federal Aviation Regulations (FAR) section 25.1401 (f). The
anti-collision light(s) may therefore satisfy the FAR requirements
for anti-collision lights both in terms of color and light
intensity, while providing a clear indication of an unmanned aerial
vehicle via the two-color or three-color light flashes within the
flash duration interval.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Further exemplary embodiments of the invention are described
below with reference to the enclosed drawings, wherein:
[0034] FIG. 1 shows an unmanned aerial vehicle in accordance with
an exemplary embodiment of the invention in a schematic top
view;
[0035] FIG. 2 shows an anti-collision light in accordance with an
exemplary embodiment of the invention in a schematic
cross-sectional view;
[0036] FIG. 3 shows a flash sequence as emitted in operation by the
anti-collision light of FIG. 2;
[0037] FIG. 4 shows an anti-collision light in accordance with
another exemplary embodiment of the invention in a schematic
cross-sectional view;
[0038] FIG. 5 shows a flash sequence as emitted in operation by the
anti-collision light of FIG. 4;
[0039] FIG. 6 indicates exemplary color ranges, as used by methods
in accordance with exemplary embodiments of the invention, in a
1931 CIE chromaticity diagram;
[0040] FIG. 7 indicates aviation white in the 1931 CIE chromaticity
diagram;
[0041] FIG. 8A shows an unmanned aerial vehicle in accordance with
an exemplary embodiment of the invention in a schematic side view;
and
[0042] FIG. 8B shows light intensities, as emitted by
anti-collision lights in accordance with an exemplary embodiment of
the invention, when mounted to the unmanned aerial vehicle.
DETAILED DESCRIPTION
[0043] FIG. 1 shows an unmanned aerial vehicle 100 in accordance
with an exemplary embodiment of the invention in a schematic top
view. The unmanned aerial vehicle 100 is a multicopter. In
particular, the unmanned aerial vehicle 100 is a quadrocopter in
the exemplary embodiment of FIG. 1, i.e. it has four rotors. The
unmanned aerial vehicle may have a smaller or greater number of
rotors, such as eight rotors, thus operating as an octocopter. The
unmanned aerial vehicle may be an unmanned aerial vehicle at all
times or may be a generally unmanned aerial vehicle, capable of
temporarily transporting human passengers, such as an air taxi. The
unmanned aerial vehicle may be remote controlled or may be
autonomous.
[0044] The unmanned aerial vehicle 100 has a vehicle body 102. The
vehicle body 102 may be configured for carrying utilities or
delivery goods or any other kind of goods to be carried. The
vehicle body 102 comprises four rotor support arms 104. Each of the
four rotor support arms 104 supports a rotor 110.
[0045] Each of the four rotors 110 has a rotor hub 112 and two
rotor blades 114. In the exemplary embodiment of FIG. 1, the two
rotor blades 114 of each rotor 110 are separate elements, each
element individually mounted to the rotor hub 112. The two rotor
blades 114 of each rotor 110 may also be formed as an integrated
structure and may be attached to the rotor hub 112 as a single
integrated element. It is pointed out that the rotors 110 may have
larger numbers of rotor blades as well.
[0046] In operation, the rotor blades 114 rotate around the rotor
hub 112 and provide lift to the unmanned aerial vehicle 100. The
rotating speed of the rotor blades 114 of the rotors 110 are
controlled by a flight control unit of the unmanned aerial vehicle
100. By adapting the relative rotating speeds of the four rotors
110, the unmanned aerial vehicle 100 is steerable and can be flown
into desired flight directions. The mechanics of flying and
steering a multicopter are known to the skilled person.
[0047] An anti-collision light 2 is mounted to the vehicle body
102, in particular to an upper central portion of the vehicle body
102. In FIG. 1, the anti-collision light 2 is schematically shown
as a structure having a rectangular outline in the depicted
schematic top view. A further anti-collision light 2 may be mounted
to a lower central portion of the vehicle body 102. The components
of the anti-collision light 2 and its operation will be described
below.
[0048] FIG. 2 shows an anti-collision light 2 in accordance with an
exemplary embodiment of the invention in a schematic
cross-sectional view. The anti-collision light 2 is embedded into
the vehicle body 102 of an unmanned aerial vehicle in accordance
with exemplary embodiments of the invention. The anti-collision
light may also extend from the vehicle body 102, it may for example
be a dome-shaped structure extending from the vehicle body 102. For
clarity of illustration, only a small portion of the vehicle body
102 is shown in FIG. 2.
[0049] The anti-collision light 2 comprises a housing 4 and a lens
cover 6. The housing 4 and the lens cover 6 define an inner space
of the anti-collision light 2. A circuit board 8, such as a printed
circuit board, is arranged in the inner space of the anti-collision
light 2. A plurality of light sources of different colors, jointly
referred to with reference numeral 10, are arranged on the circuit
board 8. In the exemplary embodiment of FIG. 2, the plurality of
light sources of different colors 10 comprise a blue light source
16 and a yellow light source 18. Further, a white light source 20
is arranged on the circuit board 18 in the exemplary embodiment of
FIG. 2. The white light source 20 may also be omitted. In the
exemplary embodiment of FIG. 2, the blue light source 16, the
yellow light source 18, and the white light source 20 are a blue
LED, a yellow LED, and a white LED.
[0050] The light sources may be arranged in row-like configuration,
as illustrated in FIG. 2, or in a matrix configuration or in any
other suitable configuration. The light sources may emit their
light output directly towards the lens cover 6 and out of the
anti-collision light 2. They may also be associated with one or
more optical elements, such as one or more reflectors and/or one or
more lenses and/or one or more shutters, for shaping the light
intensity distribution of the light output. The lens cover 6 is
transparent for allowing the light from the light sources 16, 18,
20 to exit the anti-collision light 2.
[0051] The anti-collision light 2 further comprises a control unit
30. The control unit 30 is also arranged on the circuit board 8.
The control unit 30 is coupled to the blue light source 16, the
yellow light source 18, and the white light source 20 via wired
connections of the circuit board 8. The control unit 30 is
configured to control the blue light source 16, the yellow light
source 18, and the white light source 20. In particular, the
control unit 30 is configured to switch the blue light source 16,
the yellow light source 18, and the white light source 20 on/off.
The control unit 30 may also be arranged outside of the inner space
between the housing 4 and the lens cover 6. However, as the control
unit 30 is configured to control the light sources of the
anti-collision light 2, it is defined as part of the anti-collision
light 2, irrespective of its location.
[0052] The control unit 30 of the anti-collision light 2 is coupled
to a flight control unit of the unmanned aerial vehicle. The
control unit 30 receives information about the current operating
state of the unmanned aerial vehicle from the flight control unit
of the unmanned aerial vehicle. For example, the control unit 30
may receive information about whether the unmanned aerial vehicle
is currently in flight or on the ground.
[0053] The operation of the anti-collision light 2 of FIG. 2 is now
described with respect to FIG. 3. In FIG. 3, a sequence of light
flashes is shown, resulting from the switching of the light sources
of the anti-collision light 2 of FIG. 2 over time. FIG. 3
illustrates the sequence of light flashes for an operating
situation when the unmanned aerial vehicle is in the air. In other
words, the sequence of light flashes of FIG. 3 is based on the
assumption that the control unit 30 is aware of the unmanned aerial
vehicle being in the air and controls the plurality of light
sources of different colors 10 in accordance with this
awareness.
[0054] Between t=0 s and t=0.2 s, the anti-collision light emits
two light flashes of different colors, namely a blue light flash 40
and a yellow light flash 42. In the exemplary embodiment of FIGS. 2
and 3, the blue light flash 40 and the yellow light flash 42 do not
overlap, are of substantially the same length, and have
substantially the same intensity. In particular, the blue light
flash 40 may be emitted between t=0.01 s and t=0.09 s, and the
yellow light flash 42 may be emitted between t=0.11 s and t=0.19 s.
In this way, both of the blue light flash 40 and the yellow light
flash 42 are 80 ms in duration. It is pointed out that it is also
possible that the blue light flash 40 and the yellow light flash 42
have different durations and/or different relative light
intensities.
[0055] In the exemplary embodiment of FIGS. 2 and 3, the blue light
flash 40 is generated by switching the blue light source 16 on
between t=0.01 s and t=0.09 s, and the yellow light flash 42 is
generated by switching the yellow light source 18 on between t=0.11
s and t=0.19 s.
[0056] The time frame between t=0 s and t=0.2 s is also referred to
as a flash duration interval 80. Accordingly, the blue light flash
40 and the yellow light flash 42 are emitted within the flash
duration interval 80. In the exemplary embodiment of FIGS. 2 and 3,
the flash duration interval 80 is 0.2 s long. It is also possible
that the flash duration interval 80 is shorter.
[0057] The time frame between t=0 s and t=0.2 s is referred to as a
flash duration interval 80, because the individual blue and yellow
light flashes within the flash duration interval 80 may be counted
as a single flash according to particular standards/practices in
the field of aircraft lighting. For example, Aerospace Standard
AS8017-D says that multiple flashes may be counted as a single
flash for the purpose of that standard, provided they are within a
time frame of 0.2 s. In this way, while being clearly discernible
as two individual flashes of different colors for an observer, the
blue and yellow light flashes 40, 42 between t=0 s and t=0.2 s may
be counted as a single flash for the purpose of particular
standards/practices in the field of aircraft lighting.
[0058] Besides being counted as a single flash, the blue light
flash 40 and the yellow light flash 42 between t=0 s and t=0.2 s
may be jointly considered as a white light flash. In addition to
being counted as a single flash, the colors within the flash
duration interval 80 may be added. With blue and yellow adding up
to white according to color addition rules, the overall color
emitted within the flash duration interval 80 may be considered to
be white. This approach may be thought of as pointing a photo
camera towards the anti-collision light 2, opening the shutter at
t=0 s, and setting the camera shutter time to 0.2 s. In
mathematical terms, the approach may be thought of as integrating
the light output from the anti-collision light 2 over the flash
duration interval 80. Such an integration may take into account
different light intensities and different lengths of the individual
light flashes within the flash duration interval.
[0059] In this way, an anti-collision light output may be achieved
that is discernible as a sequence of flashes of different colors to
an observer, while counting as a single white flash for particular
standards/practices in the field of aircraft lighting. A clear
distinction between unmanned aerial vehicles and traditional,
manned aircraft may be achieved, while maintaining compliance with
existing standards/practices for anti-collision lights.
[0060] The anti-collision light 2 is configured to repeat the
emission of a blue light flash 40 and a yellow light flash 42
within a respective flash duration interval 80, as long as the
unmanned aerial vehicle is in the air. This is illustrated in FIG.
3 by another pair of blue and yellow light flashes 40, 42 between
t=1 s and t=1.2 s. The given pattern of blue and yellow light
flashes 40, 42 within according flash duration intervals 80 and of
light emission breaks of about 0.8 s between the flash duration
intervals 80 may be continued, as long as the unmanned aerial
vehicle is in the air.
[0061] It is pointed out that t=0 s is arbitrarily defined for
illustrating the exemplary sequence of light flashes of different
colors, as emitted by the exemplary anti-collision light 2. The
starting point t=0 s may also be defined somewhere between two
flash duration intervals 80 or at some point in time before the
unmanned aerial vehicle takes off.
[0062] It is further pointed out that the light emission breaks
between the flash duration intervals 80 may be shorter or longer
than the depicted about 0.8 s. For example, the breaks may be
between 0.4 s and 1.5 s long.
[0063] In case the unmanned aerial vehicle in question is an air
taxi, capable of transporting passengers, the described flash
pattern of blue and yellow flashes may be emitted when no
passengers are aboard. When one or more passengers are aboard, the
control unit 30 may control the blue light source 16 and the yellow
light source 18 to remain off. Instead, the control unit 30 may
control the white light source 20 to emit white light flashes. In
this way, the anti-collision light output from the anti-collision
light 2 may resemble the traditional white strobe anti-collision
lighting, as expected from traditional passenger aircraft, thus
indicating a momentary state of passenger transport.
[0064] FIG. 4 shows an anti-collision light 2 in accordance with
another exemplary embodiment of the invention in a schematic
cross-sectional view. The anti-collision light 2 of FIG. 4 is
similar to the anti-collision light 2 of FIG. 2. Reference is made
to the description of FIG. 2 above, with the differences between
the anti-collision light 2 of FIG. 4 and the anti-collision light 2
of FIG. 2 being described as follows.
[0065] In the exemplary anti-collision light 2 of FIG. 4, the
plurality of light sources of different colors 10 comprise a cyan
light source 12, a red light source 14, a blue light source 16, and
a yellow light source 18. In the exemplary embodiment of FIG. 4,
the cyan light source 12, the red light source 14, the blue light
source 16, the yellow light source 18, and the white light source
20 are a cyan LED, a red LED, a blue LED, a yellow LED, and a white
LED. The control unit 30 is configured to control the cyan light
source 12, the red light source 14, the blue light source 16, the
yellow light source 18, and the white light source 20. In
particular, the control unit 30 is configured to switch the cyan
light source 12, the red light source 14, the blue light source 16,
the yellow light source 18, and the white light source 20
on/off.
[0066] The operation of the anti-collision light 2 of FIG. 4 is now
described with respect to FIG. 5. In FIG. 5, a sequence of light
flashes is shown, resulting from the switching of the light sources
of the anti-collision light 2 of FIG. 4 over time. FIG. 5
illustrates the sequence of light flashes for an operating
situation when the unmanned aerial vehicle is in the air. In other
words, the sequence of light flashes of FIG. 5 is based on the
assumption that the control unit 30 is aware of the unmanned aerial
vehicle being in the air and controls the plurality of light
sources of different colors 10 in accordance with this
awareness.
[0067] As compared to the sequence of light flashes of FIG. 3, the
sequence of light flashes of FIG. 5 has three light flashes of
different colors within each flash duration interval 80. In
particular, within each flash duration interval 80, there are a
cyan light flash 50, a magenta light flash 52, and a yellow light
flash 54. In the exemplary embodiment of FIGS. 4 and 5, the cyan
light flash 50, the magenta light flash 52, and the yellow light
flash 54 do not overlap, are of substantially the same length, and
have substantially the same intensity. In particular, in the flash
duration interval from t=0 s to t=0.2 s, the cyan light flash 50
may be emitted between t=0.01 s and t=0.06 s, the magenta light
flash may be emitted between t=0.07 s and t=0.12 s, and the yellow
light flash 54 may be emitted between t=0.13 s and t=0.18 s. In
this way, all three of the cyan light flash 50, the magenta light
flash 52, and the yellow light flash 54 are 50 ms in duration. It
is pointed out that it is also possible that the cyan light flash
50, the magenta light flash 52, and the yellow light flash 54 have
different durations and/or different relative light
intensities.
[0068] In the exemplary embodiment of FIGS. 4 and 5, the cyan light
flash 50 is generated by switching the cyan light source 12 on, the
magenta light flash 52 is generated by switching the red light
source 14 and the blue light source 16 on, and the yellow light
flash 54 is generated by switching the yellow light source 18
on.
[0069] The colors cyan, magenta, and yellow also add up to white.
With the cyan light flash 50, the magenta light flash 52, and the
yellow light flash 54 being provided within the flash duration
interval 80, the combination of the cyan light flash 50, the
magenta light flash 52, and the yellow light flash 54 may be
considered a single white light flash according to particular
standards/practices in the field of aircraft lighting.
[0070] In this way, the flash sequence of FIG. 5 provides an
alternative solution for achieving an anti-collision light output
that is discernible as a sequence of flashes of different colors to
an observer, while counting as a single white flash for particular
standards/practices in the field of aircraft lighting. A clear
distinction between unmanned aerial vehicles and traditional,
manned aircraft may be achieved, while maintaining compliance with
existing standards/practices for anti-collision lights.
[0071] FIGS. 6 and 7 illustrate the concept of color addition, as
made use of in the anti-collision light output of exemplary
embodiments of the present invention, in the framework of the 1931
CIE chromaticity diagram. FIG. 6 is a grey-scale representation of
said diagram. While the diagram is per definition in color, the
grey-scale allows for illustrating the concept of color addition.
Also, the 1931 CIE chromaticity diagram is readily available to the
public, such that the explanations given herein can be easily read
in conjunction with a color version of the 1931 CIE chromaticity
diagram. A color version of the 1931 CIE chromaticity diagram is
incorporated herein by reference.
[0072] FIG. 7 indicates a polygon 70 that represents the definition
of aviation white light, as given by the Federal Aviation
Regulations (FAR), and a polygon 72 that represents the definition
of aviation white light, as given by SAE AS8017-D. As described
above, exemplary embodiments of the present invention rely on using
colors for the plurality of light flashes within the flash duration
interval that add up to white. In the context of FIG. 7, this
approach means that the colors used within a flash duration
interval may add up to a shade of white, contained within polygon
70 and/or polygon 72.
[0073] When looking at FIG. 6 in conjunction with FIG. 7, it can be
seen that the adding of a blueish color, as highly schematically
indicated by circle 66, and a yellowish color, as highly
schematically indicated by circle 68, may lead to a shade of white
within polygon 70 and/or polygon 72. In this context, the addition
of colors yields a color shade that is on the connecting line
between the shade of blue used and the shade of yellow used.
[0074] Similarly, when looking at FIG. 6 in conjunction with FIG.
7, it can be seen that the adding of a cyan color, as highly
schematically indicated by circle 62, and a magenta color, as
highly schematically indicated by circle 64, and a yellowish color,
as highly schematically indicated by circle 68, may lead to a shade
of white within polygon 70 and/or polygon 72. In this context, the
addition of colors yields a color shade that is within the triangle
given by the connection lines between the shade of cyan used, the
shade of magenta used, and the shade of yellow used.
[0075] It is pointed out that above described color adding may
yield a color shade within the definition of aviation white,
without using red or green colors. In this way, none of the
plurality of light flashes within the flash duration interval is
green or red, thus staying away from colors that are reserved for
navigation lights. Instead, the desired color adding may be
achieved with colors that have no specified meanings on airborne
aircraft, as of now. In this way, the confusion with other aircraft
signalling may be kept low or may even be prevented.
[0076] FIG. 8A shows an unmanned aerial vehicle 100 in accordance
with an exemplary embodiment of the invention in a schematic side
view. The unmanned aerial vehicle 100 may be the unmanned aerial
vehicle 100 of FIG. 1, depicted in a side view. Accordingly, the
unmanned aerial vehicle 100 of FIG. 8 is a quadrocopter, with two
of the rotors being shown in the side view of FIG. 8. With respect
to the description of the vehicle body 102, the rotor support arms
104, and the rotors 110, having rotor hubs 112 and rotor blades
114, reference is made to the description of FIG. 1 above.
[0077] The unmanned aerial vehicle 100 of FIG. 8 has an upper
anti-collision light 2, mounted to an upper portion of the vehicle
body 102, and a lower anti-collision light 2, mounted to a lower
portion of the vehicle body 102. In the exemplary embodiment of
FIG. 8, the upper and lower anti-collision lights 2 extend
upwards/downwards from the upper/lower portion of the vehicle body
102. In particular, each of the upper and lower anti-collision
lights 2 has a dome-shaped lens cover, which extends above/beyond
the vehicle body 102. The light sources, control unit, and other
components may be analogous to any of the embodiments described
above with respect to FIGS. 2 and 4.
[0078] As compared to the anti-collision lights 2 of FIGS. 2 and 4,
which are embedded into the vehicle body, the extension
above/beyond the vehicle body 102 allows for an elevated
positioning of the light sources with respect to the vehicle body
and thus for a less complex directing of light into a wide range of
directions, in particular a less complex directing of light into or
close to the horizontal plane. It is pointed out that
anti-collision lights in accordance with exemplary embodiments of
the invention may alternatively or additionally be provided at
other positions of the unmanned aerial vehicle, such as on the side
faces of the vehicle body and/or on the rotor support arms.
[0079] FIG. 8B illustrates light intensity distributions that
reflect the requirements of Federal Aviation Regulations (FAR)
section 25.1401. The light intensity distributions are shown as
angular distributions with respect to horizontal planes 200. In
particular, the light intensity distributions are shown in a
vertical cross-sectional plane that is orthogonal to a horizontal
plane through the unmanned aerial vehicle 100. As the FAR
requirements are given as a rotationally symmetric distribution,
i.e. as a distribution that is identical in all viewing directions
from the anti-collision light, the shown light intensity
distributions would look the same in all vertical cross-sections
through the center of the upper anti-collision light and through
the center of the lower anti-collision light, respectively.
[0080] The depicted light intensity distribution of FIG. 8B is as
follows. A light intensity of 400 cd is indicated for an angular
range of between 0.degree. and 5.degree. with respect to the
horizontal plane 200. A light intensity of 240 cd is indicated in
an angular range of between 5.degree. and 10.degree. with respect
to the horizontal plane 200. A light intensity of 80 cd is
indicated in an angular range between 10.degree. and 20.degree.
with respect to the horizontal plane 200. A light intensity of 40
cd is indicated in an angular range of between 20.degree. and
30.degree. with respect to the horizontal plane 200. A light
intensity of 20 cd is indicated in an angular range of between
30.degree. and 75.degree. with respect to the horizontal plane 200.
The light intensity values, shown as angular sectors in FIG. 8B,
represent minimum light intensity values, as spelled out by the
FAR.
[0081] Anti-collision lights in accordance with exemplary
embodiments of the invention may have anti-collision light outputs
that fulfill these FAR requirements. It is possible that one
anti-collision light in accordance with an exemplary embodiment of
the invention has an anti-collision light output that fulfills the
FAR requirements for the upper hemisphere or the lower hemisphere.
It is also possible that multiple anti-collision lights are
arranged around the perimeter of the unmanned aerial vehicle and
jointly fulfill the FAR requirements for both the upper hemisphere
and the lower hemisphere. The expressions of the anti-collision
light output(s) fulfilling the FAR requirements or satisfying the
FAR requirements or being in accordance with the FAR requirements
is to be understood as the anti-collision light output(s) reaching
or exceeding the minimum light intensity values, as described
above.
[0082] While the invention has been described with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition many modifications may be made to
adopt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed, but that the invention include all
embodiments falling within the scope of the following claims.
* * * * *