Patent Description:
There are a large number of signalling devices at aerodromes, such as lighting devices, which may be located in particular on or in the vicinity of aprons, ramps, taxiways or runways, or else, for example, on buildings such as hangars, on the air traffic control (ATC) tower or on other facilities. Signalling devices may also include, for example, radar devices or radio beacons.

Aerodrome signalling systems having a control unit and a central communication unit able to communicate with a plurality of signalling devices are known from <CIT>, <CIT> and <CIT>. The signalling devices are connected to the control unit and the central communication unit via a power supply line. Communication between the central communication unit and the signalling devices is performed via the power supply line through an orthogonal frequency-division multiplexing (OFDM) technique in which the data stream is split across a number of narrowband channels in a limited frequency range to reduce interference and crosstalk. The signalling devices comprise at their end an addressable communication gateway device able to communicate with the central communication unit. The data communication via the power supply line can include control commands for operating the signalling devices, and may include measurement data captured by sensors arranged in proximity of the signalling devices.

Along the power supply line galvanic insulating transformers are arranged at each node with a signalling device. The communication gateway devices ae arranged at the secondary side of the transformers, at the side of the signalling device. Since these transformers typically attenuate high frequency signals, dedicated transformers must be used allowing high frequency signals to pass through, increasing installation costs. Yet, the usable frequency bands are typically limited to about <NUM>, limiting the data bandwidth.

Most aerodrome signalling devices, in particular aeronautic ground lighting (AGL), are arranged as series circuits. Such a topology further limits the amount of information that can be passed through the circuit for monitoring the operational conditions of the signalling system. The bandwidth does not allow to pass additional information obtained from various sensor or historical data stored at the device. Furthermore, for security reasons, status condition information is typically stored centrally within the signalling system, with limited accessibility by maintenance personnel.

There is therefore a need in the art of providing a network of distributed sensors on an aerodrome in an economic way for increasing safety. There is a need in the art of providing an aerodrome signalling system allowing a higher amount of information to be communicated and gathered for improved control and maintenance of the system. There is also a need in the art of providing aerodrome signalling systems allowing easier and faster maintenance and monitoring.

According to a first aspect, there is therefore provided an aerodrome signalling system, as set out in the present disclosure and in the appended claims. An aerodrome signalling system as described herein comprises a plurality of signalling units, each comprising at least one aerodrome signalling device, and a central communication unit configured for data communication with the plurality of signalling units. The plurality of signalling units and possibly the central communication unit comprise a wireless data communication device configured for cellular communication of measurement data in relation to one or more of: an environmental condition, a meteorological condition, a presence of a (foreign) object, a movement of a (foreign) object and a status condition relating to the respective signalling unit other than a status condition of the respective at least one signalling device, and possibly further data representing a condition of the aerodrome signalling system / the at least one aerodrome signalling device, or of control signals for operating the aerodrome signalling system. The measurement data is captured by one or more sensor devices incorporated in the signalling units. The wireless data communication device can communicate or co-operate with a communication device for data communication via a power supply line through which the at least one aerodrome signalling device is supplied with electric power.

According to the present disclosure hence a network of distributed sensors over the airfield can be obtained by incorporating sensor devices in the signalling units. The sensor devices communicate with wireless communication devices provided in the light units configured to transmit data gathered by the distributed sensors over a cellular network. The present disclosure hence makes it possible to create distributed sensor networks for sensing various conditions, either outside or inside the enclosure of the signalling unit. These conditions are advantageously not related to an operating condition of the signalling device itself. Rather, the measurement data obtained from these sensor devices serves the purpose of improving air traffic control and airfield security and safety by providing a distributed system of sensors which are arranged at positions that are relevant for the airfield traffic and that gather a vast amount of data in a non-cooperative manner: meteorological conditions, which may vary from spot to spot on the airfield, environmental conditions, safety conditions of the signalling unit enclosure (water ingress, broken window, excessive vibration, etc.), and non-cooperative detection of airfield traffic enhancing existing traffic control systems. The cellular communication capability makes it possible to simultaneously transmit a vast amount of data captured by various sensor devices on the airfield.

According to a second aspect, there is provided an aerodrome signalling unit, as set out in the present disclosure and in the appended claims. A plurality of such signalling units allow to provide the aerodrome signalling system of the first aspect.

According to a third aspect of the present disclosure, there is provided a control unit for an aerodrome signalling system, and a management system for an aerodrome signalling system. The control unit is advantageously comprised in the aerodrome signalling system of the first aspect. The management system is advantageously implemented in the aerodrome signalling system of the first aspect.

According to a fourth aspect of the present disclosure, there is provided a method of operating an aerodrome signalling system, such as the aerodrome signalling system of the first aspect.

Referring to <FIG>, a signalling system <NUM> for an aerodrome, such as an airport, comprises a control unit <NUM> and a plurality of signalling units <NUM>. The control unit comprises a power supply device <NUM>, such as a constant current regulator (CCR), or a distributed parallel power system. The signalling units <NUM> are connected to the power supply device <NUM> via a power supply line <NUM>. The power supply line <NUM> forms a series power supply circuit to which the signalling units <NUM> are connected in series. The power supply line <NUM> could, however, also form a parallel power circuit with the signalling units <NUM> connected in parallel.

The signalling units <NUM> comprise one or more signalling devices and one or more sensor devices. The signalling devices may refer to lighting devices, such as aeronautic ground lighting (AGL) devices as defined in ICAO (International Civil Aviation Organisation) Annex <NUM>. The signalling devices may alternatively or additionally refer to visual guidance devices such as stop bars and airfield light signs. The sensor devices may refer to sensors suitable for use at an aerodrome site, such as direction sensors, sensors for aircraft detection and aircraft classification, torque sensors (e.g. for sensing or monitoring the torque applied by a bolt) and vibration sensors. The sensor devices may alternatively or additionally refer to, for example, devices for detection of wind direction and intensity and signalling thereof, as well as other types of detection and signalling apparatuses for meteorological or environmental data, such as temperature, humidity and light conditions. The signalling devices may alternatively or additionally refer to sensors for detection of gas and/or water in cable ducts, as well as visual detection devices, such as video cameras, for monitoring the runway area, taxiway area, Apron, and any other area of the aerodrome or airfield. It will be convenient to note that all the above sensors refer to non-cooperative sensors. In particular, these sensors do not co-operate with the aircraft or vehicle passing by, e.g. they are not configured to intercept signals emitted by such aircrafts or vehicles to make the detection.

The control unit <NUM> of the aerodrome signalling system <NUM> further comprises a central communication unit <NUM>. The central communication unit <NUM> is advantageously looped in to the supply line <NUM>. The signalling units <NUM> are therefore connected via the same supply line <NUM> to both the power supply device <NUM> and the central communication unit <NUM>.

The central communication unit <NUM> is connected, e.g. via a data communication network <NUM>, to a master control unit <NUM>, which may be provided in proximity of the central communication unit <NUM>, or remotely. The central communication unit <NUM> can receive from the master control unit <NUM> setpoint data which it forwards to the signalling units <NUM>. Additionally, the central communication unit <NUM> can receive from the signalling units <NUM> status reports which it forwards to the master control unit <NUM>. The master control unit <NUM> is in this way configured to operate as an aerodrome management system, as described, for example, in <CIT>, <CIT> or <CIT>.

Referring to <FIG>, each signalling unit <NUM> comprises a base body <NUM> in which one or a plurality of signalling devices, such as a lighting device <NUM>, and one or more sensor devices <NUM> as described above, and a local control unit <NUM> are arranged. Connection terminals <NUM> are provided in the base body <NUM> for connecting the one or more signalling devices <NUM>, <NUM> to the power supply line <NUM>. A switching device <NUM> can further be provided. The lighting device <NUM> can comprise one or a plurality of lights. The switching device <NUM> is configured to operate the lighting device <NUM>, and/or any other switchable sensor device <NUM> arranged in the base body <NUM>. The switching device <NUM> and the local control unit <NUM> are connected to the connection terminals <NUM>.

Referring again to <FIG>, a transformer <NUM> is connected to the connection terminals <NUM>. The transformer <NUM> enables the connection of the signalling units <NUM> to the power supply line <NUM> while ensuring galvanic insulation. The connection can be effected via spur lines <NUM>' which can have a line length up to <NUM>, preferably <NUM> or less. Alternatively, the transformer is connected downstream of the connection terminals <NUM>, e.g. between connection terminals <NUM> and switching device <NUM> and/or local control unit <NUM>. Transformer <NUM> can be provided outside, or inside base body <NUM>.

According to one aspect, the central communication unit <NUM> comprises a first communication gateway device <NUM> coupled to a radio antenna <NUM>. First communication gateway device <NUM> is configured for cellular data communication via antenna <NUM>. The cellular data communication can be effected by the first gateway device <NUM> according to any suitable wireless data communication protocol for cellular radio communications, e.g. based on orthogonal frequency division multiplexing (OFDM), such as <NUM>, <NUM>, etc. The central communication unit <NUM> can additionally, or alternatively comprise a second communication gateway device <NUM>, configured for wired data communication. In particular, second communication gateway device <NUM> is connected to power supply line <NUM> and configured for superimposing a communication signal on the power signal (voltage and/or current) through power supply line <NUM>.

Referring again to <FIG>, the local control unit <NUM> comprises a processing device <NUM>, such as a microprocessor, and a third communication gateway device <NUM> coupled to a radio antenna <NUM>. Third communication gateway device <NUM> is configured for cellular data communication via antenna <NUM>. The cellular data communication can be effected by the third gateway device <NUM> according to any suitable wireless data communication protocol for cellular radio communications, e.g. based on orthogonal frequency division multiplexing (OFDM), such as <NUM>, <NUM>, etc. In addition, or alternatively, the local control unit <NUM> comprises a fourth communication gateway device <NUM> configured for wired data communication, in particular via power supply line <NUM>. The third communication gateway device <NUM> and the fourth communication gateway device <NUM> are operably coupled to processing device <NUM>.

According to one aspect, the first and the third communication gateway devices <NUM> and <NUM> are configured to communicate with one another, either unidirectionally, or bidirectionally, via respective antennas <NUM> and <NUM>. The second and the fourth communication gateway devices <NUM> and <NUM> are configured to communicate with one another, either unidirectionally, or bidirectionally, advantageously via power supply line <NUM>.

The central communication unit <NUM> is configured to transmit control signals S to the local control unit <NUM> of each signalling unit <NUM>. The transmission of control signals S can be effected in different ways. According to a first possibility, as can be seen from <FIG> and <FIG>, control signals S are communicated as a message signal <NUM> via power supply line <NUM>. In particular, signals S are superimposed on the AC (<NUM> or <NUM>) voltage or current signal fed via power supply line <NUM> for supplying power to the signalling devices <NUM>, <NUM>. By way of example, signal S can be superimposed as an OFDM signal as described above, which can comprise one or more non-overlapping narrowband frequency channels, advantageously in a frequency range between <NUM> and <NUM>. The frequency channels can be parameterized by the second or fourth communication gateway devices. Alternatively, signal S can be superimposed by time slot synchronization and using a controlled high impedance at the secondary side of the transformers <NUM> for communicating pulses contained in pulse signals, as described in <CIT>. It will be appreciated that yet alternative power line communication techniques as known in the art may be used in the systems described herein, in particular frequency modulation schemes for data communication, such as frequency-shift keying (FSK) signals transmitted via the power supply line.

The control signals S are transmitted by the second communication gateway device <NUM> as a superimposed message signal <NUM> via power supply line <NUM>, and are received by the fourth communication gateway device <NUM>. Each fourth communication gateway device <NUM> of the signalling units <NUM> can be separately addressable by the second communication gateway device <NUM> to receive a dedicated control signal S. The control signals S received by the fourth communication gateway device <NUM> are transferred to processing device <NUM> which is configured to process the control signals S for e.g. operating switching device <NUM> and/or one or more signalling devices <NUM>, <NUM>. Suitable examples of control commands are switching ON or OFF of the lighting device <NUM>, controlling the light intensity of lighting device <NUM>, querying a sensor device <NUM>.

According to a second possibility, the control signals S are communicated as a wireless signal between the central communication unit <NUM> and the signalling units <NUM>. To this end, the control signals S are transmitted by the first communication gateway device <NUM> via antenna <NUM> and are received by the third communication gateway device <NUM> of the signalling unit <NUM> via antenna <NUM>. As already indicated above, the wireless communication between antenna <NUM> and antenna <NUM> can be effected according to any suitable cellular radio communication network protocol, such as <NUM>, specifically within a mission critical cellular private network.

The central communication unit <NUM> can be configured to select an appropriate transmission route for the control signals S, i.e. via a wired (devices <NUM>/<NUM>) or wireless (devices <NUM>/<NUM>) route. By way of example, the central communication unit <NUM> can be configured to select the transmission route based on the type of control signal S, e.g. control signals relating to operating the lighting device <NUM> sent via power supply line <NUM>, whereas control signals relating to operating the sensor devices <NUM> sent wirelessly.

Either one of communication gateway devices <NUM> and <NUM> can be configured as a base station to set up a cellular communication network through which data can be transmitted via communication gateway devices <NUM>, <NUM> and respective antennas <NUM> and <NUM>. Alternatively, or in addition an external or remote device is configured as a base station to set up this cellular communication network. Communication gateway devices <NUM>, <NUM> advantageously act as transceivers in the cellular network. The cellular communication network is advantageously a private cellular network, such as a private <NUM> cellular network, particularly configured for mission critical data communication. In the present disclosure, the term `<NUM>' can refer to any radio access technology operating according to the International Mobile Telecommunications-<NUM> (IMT-<NUM>) standard issued by the Radiocommunication Sector (ITU-R) of the International Telecommunication Union (ITU), and/or according to any one of the <NUM> radio access technologies set out by the 3GPP (<NUM>rd Generation Partnership Project) consortium, such as but not limited to <NUM> NR (New Radio), LTE-M (Machine Type communication) and NB-loT (Narrowband Internet-of-Things). In the context of the present disclosure, the term `<NUM>' can additionally refer to any further evolving cellular communication technology, such as <NUM> and 6GE, and which advantageously allows setting up private, i.e. non-public cellular radio communication networks, specifically for mission critical communication.

Referring to <FIG>, the sensor device <NUM> can comprise a first sensor <NUM> and/or a second sensor <NUM>. By means of the first sensor <NUM>, an internal state of the lighting (signalling) device <NUM> can be detected and transmitted to the local control unit <NUM>. For example, by means of the first sensor <NUM> it can be detected whether an electric current is flowing through the lighting device <NUM>, or whether the lighting device <NUM> is emitting light, and possibly at which light intensity. The processing unit <NUM> can receive a measurement signal R from the first sensor and determine, e.g. in conjunction with the (known) switching state of switching device <NUM>, whether the lighting device <NUM> is defective. A corresponding monitoring message M (e.g. switched on / switched off / flashing / defective) can optionally be transmitted by the local control unit <NUM> via the third gateway device <NUM> (wirelessly via antenna <NUM>), or via the fourth gateway device <NUM> (e.g. as OFDM signal) to the central communication unit <NUM>.

The second sensor <NUM> is configured to detect a state which prevails in the environment outside the signalling unit <NUM> or base body <NUM>, e.g. a weather condition (temperature, humidity), or an environmental condition (ambient light intensity, day or night), or to detect objects passing by, such as aircraft or vehicles, in a non-cooperative manner. The second sensor can e.g. be configured as a magnetic-field sensor. The presence or absence of an object <NUM> can be detected by means of the magnetic-field sensors <NUM>, particularly if the signalling unit <NUM> is installed in a take-off runway, a landing runway or a taxiway of an aerodrome. This applies particularly when the object <NUM> is a metal object, e.g. an aircraft <NUM> or a motor vehicle. When two second sensors <NUM> are arranged at a spaced apart distance along a motion direction (either in a same signalling unit <NUM>, or in two different signalling units <NUM>), the speed of the object <NUM> can also be determined. Alternatively, the second sensor <NUM> can be configured as a radar sensor, e.g. a microwave transceiver. In a further example, the second sensor <NUM> can be configured to detect a meteorological or environmental characteristic. The meteorological or environmental characteristic can, for example, be the temperature, the wind speed, precipitation (e.g. rain, snow) or visibility conditions (e.g. day/night/fog).

Other characteristics can alternatively or additionally be detected by means of the sensor device <NUM> or <NUM>. Examples of such characteristics are vibrations, (external) noise, air or ground humidity, photometrics and internal states or operational conditions of the signalling unit <NUM> other than states or operational conditions referring to the lighting (signalling) device <NUM>, the latter being captured by the first sensor <NUM>. Any suitable sensor can be used for this purpose. Some examples of the second sensor <NUM> can be configured to monitor an operational condition of the base body <NUM> and/or any other structure related to the signalling unit <NUM> other than the lighting (signalling) device <NUM>, e.g. torque sensors sensing the torque applied by e.g. a bolt and/or sensors for detection of gas and/or water, e.g. to monitor sealing conditions of the base body <NUM>, such as broken window or loosened cover. Furthermore, the detection of objects and their identification can also be effected with non-cooperative sensors other than radar or magnetic-field sensors. For example, optical sensors (e.g. cameras) can be used, by which not only the presence of an object but also its shape and/or movement and movement direction may be detected.

The signal R generated by the second sensor <NUM> can be transmitted to the local control unit <NUM>, which is processed by the processing device <NUM> to determine a useful signal N therefrom. The useful signal N can be transmitted by the local control unit <NUM> via the third communication gateway device <NUM> (wirelessly via antenna <NUM>), or via the fourth communication gateway device <NUM> (e.g. as OFDM signal) to the central communication unit <NUM>.

If the signalling units <NUM> operate on the basis of synchronization on a shared time base, it is also possible to transmit through signal N the respective detection time to the central communication unit <NUM>. To this end, a time synchronization signal is advantageously received through antenna <NUM> and the third communication gateway device <NUM>, e.g. within a mission critical private cellular radio communication network.

The local control unit <NUM> can further be configured to transmit to the central communication unit <NUM> a signal transmission request e.g. in the form of an interrupt request IR. This can be effected either via the fourth communication gateway device <NUM>, as a superimposed message signal <NUM> via power supply line <NUM>, or wirelessly - if applicable according to the communication protocol used - via the third communication gateway device <NUM>. If, for example, one of the local control units <NUM> notices a defect in the lighting device <NUM>, it can send a signal transmission request IR to the central communication unit <NUM>, allowing the central communication unit <NUM> to address in a targeted manner the local control unit <NUM> from which the signal transmission request IR originated. The signal transmission request IR can comprise, in addition to an identifier of the signalling unit <NUM> (local control unit <NUM>), a code, from which the central communication unit <NUM> can recognize the type of signals to be transmitted. For example, different codes can be used for recognizing an object <NUM>, for modifying a meteorological identifying characteristic or for modifying an internal state of the aerodrome signalling unit (e.g. failure of the lighting device <NUM>).

It is alternatively possible for the local control units <NUM> to feed not only an interrupt request IR, but along with it also the useful signal N itself to the central communication unit <NUM>. Such type of transmission, however, requires some form of collision monitoring, as known in the art.

It will be appreciated that the wired communication via the second and fourth communication gateway devices <NUM>, <NUM> can proceed through other cables than the power supply line, e.g. through dedicated data communication cables, such as optical fibres, when available.

It will be convenient to note that base body <NUM> can comprise a plurality of pairs of connection terminals <NUM> connected to one or more distinct signalling devices. The pairs of connection terminals <NUM> may be connected to distinct transformers <NUM>. Base body <NUM> can hence refer to different types of installation enclosures, such as an in-ground pit, a manhole or an in-ground or elevated base.

Typically, transformers <NUM> are optimized for power transmission frequencies, but not for data signal transmission frequencies. They can therefore significantly dampen the transmitted data signals S, M, N, IR. To avoid such problems, dedicated transformers having reduced high frequency damping characteristics can be used, but at a penalty of increased cost. In addition, or alternatively, the second and fourth communication gateway devices <NUM>, <NUM> preferably comprise repeaters for signal conditioning and amplification and means for measuring the reception strength and quality of the signals S, M, N, IR transmitted via the power supply line <NUM> as superimposed message signals. The reception strength and quality is also preferably transmitted via the power supply line <NUM> to the central communication unit <NUM>. This advantageously allows the central communication unit <NUM> to monitor the condition of the overall communication system. By evaluating the information transmitted about transmission quality and signal strength, the central communication unit <NUM> is consequently advantageously able to configure the communication system for each individual transmission operation. In particular, the central communication unit <NUM> can, by transmitting corresponding control signals S, stipulate which of the fourth communication gateway devices <NUM> is to perform repeater functions in each case and which not. In this way, adequate transmission quality in the communication system is constantly ensured. At the same time, the power outlay needed for this, as well as crosstalk behaviour and background noise, can be optimized through dynamic adaptation of the wired communication network.

Referring to <FIG>, an alternative embodiment of a signalling unit <NUM> differs from the signalling unit <NUM> of <FIG> in that it comprises a fifth communication gateway device <NUM> for cellular communication which is connected to the power supply line <NUM> through a connection node <NUM> upstream of transformer <NUM>. The fifth communication gateway device <NUM> comprises a power line communication module <NUM> allowing to transmit and/or receive signals via power supply line <NUM>, which may be similar to the fourth communication gateway device <NUM>, and a cellular communication module <NUM> for wireless (cellular) communication of signals via antenna <NUM>. The fifth communication gateway device <NUM> can be configured to wirelessly transmit, via antenna <NUM> through a cellular communication network, any data signals received via power supply line <NUM>, or to feed into power supply line <NUM> any data signal received via antenna <NUM>.

The fifth communication gateway device <NUM> can be coupled to the local control unit <NUM> for data communication through a (wired) data communication line <NUM>. In this case, the fifth communication gateway device <NUM> can replace either one of the third and fourth communication gateway devices <NUM> and <NUM>, or both, which therefore may be absent from the local control unit <NUM>. In the example of <FIG>, the fourth communication gateway device <NUM> is provided, whereas the third communication gateway device <NUM> is not provided.

One advantage of the fifth communication gateway device <NUM> is that it allows to provide a direct interface between the power supply line communication and the cellular communication network, bypassing the transformer <NUM>. Consequently, the power line communication module <NUM> suffers much less from signal dampening by transformer <NUM>. As a result, cheaper transformers <NUM> can be used and/or signal repeaters or conditioners can be dispensed with, resulting in more economical communication gateway devices. Furthermore, the network communication protocols implemented for power supply line communication may feature some similarities with the cellular network communication protocols used for wireless transmission via antenna <NUM>, e.g. OFDM. By providing a direct link between the communication modules <NUM> and <NUM>, signal conversion between the power line communication and the wireless (cellular) communication can be made easier.

Antenna <NUM> coupled to communication gateway device <NUM>, <NUM>, <NUM> or <NUM> as the case may be is advantageously configured to emit and/or receive radio signals in a frequency range defined by the cellular communication protocol (cellular network) that is used, e.g. <NUM>. As shown in <FIG> and <FIG>, antenna <NUM> is advantageously arranged outside base body <NUM> for optimal reception and/or transmission. Alternatively, antenna <NUM> can be arranged inside base body <NUM>, or integrated into the body of base body <NUM>. In these latter cases, base body <NUM> is advantageously made of a material that is transparent to radio waves, in particular in the frequency range used by antenna <NUM>, such as a non-conducting material, a composite material, or both.

Referring to <FIG>, the fifth communication gateway device <NUM> is particularly useful in larger manhole installations <NUM>, in which multiple signalling devices <NUM>, e.g. relating to a same or different aerodrome signalling circuits, and each provided with a distinct transformer <NUM> and local control unit <NUM>, are arranged. In that case, it may be economical to provide just a single communication gateway device <NUM> with communication capability with the power supply lines <NUM>, <NUM>" of each of the different signalling circuits. The fifth communication gateway device <NUM> can be operably coupled to each of the local control units <NUM> via a (wired) data communication line <NUM>. In this case, the fifth communication gateway device <NUM> can replace either one or both the third and fourth communication gateway devices <NUM>, <NUM> of the local control units <NUM>. Hence, the local control units <NUM> do not need to comprise either one or both the third and fourth communication gateway devices <NUM> and <NUM>.

Alternatively, the fifth communication gateway device <NUM> can communicate with the fourth communication gateway devices <NUM> of the local control units <NUM> of the various signalling devices via power line communication module <NUM>. This can be effected via message signals sent via the power supply lines <NUM>, <NUM>" (superimposed on the power signals). In this case, the data communication line <NUM> can be dispensed with. The power line communication module <NUM> is connected with the cellular communication module <NUM> for receiving and/or transmitting any data signals through a cellular network. The cellular communication module <NUM> can hence operate as a cellular communication gateway device for the local control units <NUM>, which do not need to be provided with a third communication gateway device <NUM>.

Referring to <FIG>, yet another embodiment of a signalling unit <NUM> differs from signalling unit <NUM> of <FIG> in that one or more signalling devices <NUM>, <NUM> comprise their own, distinct cellular communication gateway device <NUM>, <NUM> directly coupled thereto. By way of example, the sensor (signalling) device <NUM> comprises a dedicated cellular communication gateway device <NUM> and respective antenna <NUM>. The sensor (signalling) device <NUM> comprises a dedicated cellular communication gateway device <NUM> and respective antenna <NUM>. The cellular communication gateway devices <NUM>, <NUM> may or may not be operably connected to the local control unit <NUM>, i.e. direct data communication between local control unit <NUM> and cellular communication gateway devices <NUM>, <NUM> may or may not be possible.

Cellular communication gateway devices <NUM>, <NUM> may be configured to receive measurement and/or monitoring signals from the signalling devices <NUM>, <NUM> to which they are coupled, and to transmit the measurement and/or monitoring signals wirelessly via their respective antennas <NUM> over a cellular network. The local control unit <NUM> may in this case still comprise the third communication gateway device <NUM>, e.g. for cellular communication of signals, in particular control signals S, relating to operation or monitoring of the lighting device <NUM>. Alternatively, a cellular communication gateway device (not shown) can be directly coupled to lighting device <NUM>, which may or may not be operably connected to processing device <NUM>. Such a type of installation may be particularly useful in case of retrofitting existing installations, or when additional signalling devices, such as sensor or lighting devices, are added to the signalling unit <NUM> and for which no communication protocol exists via power supply line <NUM>.

It will be appreciated that some sensor devices, such as sensors <NUM>, arranged within a signalling unit <NUM>, <NUM>, <NUM>, <NUM>, can be provided with their own power sources. Alternatively, the sensor devices can draw power from the power supply line <NUM>.

Referring to <FIG>, any one of the cellular communication gateway devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM> described previously is advantageously configured to communicate with a cloud network <NUM> via a cellular network <NUM>. Cloud network <NUM> comprises a data storage system <NUM> which may store data in relation to one or more of the signalling devices <NUM>, <NUM> and/or of the power supply unit <NUM> of the signalling system <NUM>. Such data is transmitted by one or more of the various cellular communication gateway devices described hereinabove over the cellular network <NUM> and may comprise identifier data, monitoring data and/or operational data, possibly along with respective time stamps.

By way of example, the first communication gateway device <NUM> can be configured to wirelessly transmit via cellular network <NUM> monitoring data in relation to the power supply unit <NUM>, or of the overall signalling system, e.g. transformer impedance measurements, to the cloud network <NUM>. The communication gateway devices <NUM>, <NUM>, <NUM>, <NUM> can be configured to wirelessly transmit via cellular network <NUM> monitoring data in relation to a lighting device <NUM> and/or measurement data from one or more sensor devices <NUM> to the cloud network <NUM>. The cellular communication capability of the central communication unit and/or of the signalling units hence allows an increased amount of data to be transmitted. Therefore, systems as described herein allow to gather additional data in relation to operation and status condition of the signalling system <NUM> compared to the prior art systems. This data is advantageously used to improve maintenance of the signalling system, and/or to provide improved awareness relating to a malfunctioning or defect of the signalling system.

Data storage system <NUM> may be a remote system, e.g. where the data is stored in a cloud system. In this case, part or all of the data communicated from the cellular communication gateway devices of the signalling system to the cloud network <NUM> can also be stored locally, e.g. in a data storage system linked to master control unit <NUM>. Hence, the data communicated to and/or stored in cloud network <NUM> may be redundant. Alternatively, data storage system <NUM> may be a local system, e.g. arranged in the ATC tower or on the aerodrome field, and may or may not be linked to the master control unit <NUM>.

A user interface <NUM>, such as a computer, handheld tablet or mobile device, advantageously with cellular network communication capabilities, used by maintenance operators, can communicate (wirelessly, over cellular network <NUM>) with cloud network <NUM> to access the data relating to signalling system <NUM> stored in data storage system <NUM>. This allows maintenance operators to access maintenance-relevant data of the signalling system <NUM> more easily, even from remote locations.

It will be appreciated that the cellular communication gateway devices as described herein can feature any one or both of the cellular communication capabilities as described above in relation to <FIG> and <FIG>.

Claim 1:
Aerodrome signalling system (<NUM>), comprising:
a plurality of signalling units (<NUM>, <NUM>, <NUM>, <NUM>), each comprising at least one aerodrome signalling device (<NUM>),
a control unit (<NUM>, <NUM>) configured to control operation of the plurality of signalling units (<NUM>, <NUM>, <NUM>, <NUM>),
a central communication unit (<NUM>) operably coupled to the control unit and configured for data communication (S) with the plurality of signalling units (<NUM>, <NUM>, <NUM>, <NUM>),
wherein the plurality of signalling units (<NUM>, <NUM>, <NUM>, <NUM>) each comprise at least one sensor device (<NUM>) configured to capture measurement data in relation to one or more of: an environmental condition, a meteorological condition, a presence of an object, a movement of an object and a status condition relating to the respective signalling unit other than a status condition of the respective at least one signalling device,
wherein the plurality of signalling units (<NUM>, <NUM>, <NUM>, <NUM>) each comprise a first wireless data communication device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured for cellular data communication,
and wherein the at least one sensor device (<NUM>) is configured to communicate the measurement data to the first wireless data communication device for transmission via a cellular network (<NUM>).