Patent Publication Number: US-2023138515-A1

Title: Airfield Ground Light with Integrated Light Controller That Employs Powerline Communications and Sensors

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under 35 U.S.C. § 119 of U.S. Provisional Application No. 63/275,235, filed Nov. 3, 2021. The contents of the aforementioned application is hereby incorporated by reference herein in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates generally to airfield ground lights. 
     BACKGROUND 
     Regulatory agencies such as the Federal Aviation Administration (FAA), International Civil Aviation Organization (ICAO), and Civil Aviation Administration of China (CAAC) set requirements for airfield lighting systems. Systems that do not meet the requirements must be taken out of service. This requires monitoring of airfield lighting systems. 
     SUMMARY OF EXAMPLE EMBODIMENTS 
     The following presents a simplified overview of the example embodiments in order to provide a basic understanding of some aspects of the example embodiments. This overview is not an extensive overview of the example embodiments. It is intended to neither identify key or critical elements of the example embodiments nor delineate the scope of the appended claims. Its sole purpose is to present some concepts of the example embodiments in a simplified form as a prelude to the more detailed description that is presented later. 
     In accordance with an example embodiment, there is disclosed herein an airfield luminaire, comprising a housing, a light source in an interior of the housing, a sensor for sensing a condition associated with the housing, and control logic comprising a processor coupled with the light source and the sensor. The control logic is operable to obtain data from the sensor and determine a status of the airfield luminaire. Examples of the status that can be determined include but are not limited to whether there is a leak in the housing, the structural integrity of the airfield luminaire, a malfunction of the airfield luminaire, a tilt angle with respect to gravity of the light source, a directional orientation of the light source, and whether the light source is correctly aimed. 
     In accordance with an example embodiment, there is disclosed herein an apparatus comprising a controller operable to communicate with a plurality of airfield lighting fixtures. The circuit, the controller comprises logic comprising a processor operable to receive data representative of sensor data from the plurality of airfield lighting fixtures and determine the status of a selected one of the plurality of lighting fixtures based on the sensor data. Examples of the status that can be determined include but are not limited to structural integrity of an airfield lighting fixture and/or a fixture malfunction, which in an example embodiment is based on a comparison of temperature data from the selected one of the plurality of airfield lighting fixtures with other airfield lighting fixtures of the plurality of airfield lighting fixtures. 
     In accordance with an example embodiment, there is disclosed herein an apparatus, comprising control logic that comprises a processor. The processor is operable to obtain a light emitting diode (“LED”) light output aging rate for an LED, and measure operating temperature and an amount of time the LED operates at the operating temperature, which can be in real time, during operation of the LED. The controller is further operable to determine a present LED light output based on calculating the amount of degradation for a plurality of measured temperatures and a time period operating at the plurality of temperature from the LED aging rate for the plurality of temperatures from an initial light output. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings incorporated herein and forming a part of the specification illustrate the example embodiments. 
         FIG.  1    is a simplified functional block diagram illustrating an example of a light system that can be employed as an airfield luminaire. 
         FIG.  2    is a simplified functional block diagram illustrating an example of a lighting system that can be employed as an airfield luminaire that communicates control signals and/or sensor data over a powerline. 
         FIG.  3    is a block diagram illustrating an example of a light fixture with an integrated controller that employs powerline communication and illustrates different types of sensors that can be employed in the light fixture. 
         FIG.  4    is a block diagram illustrating an example of a light fixture with an additional wireless communication interface for enabling communication with portable mobile devices. 
         FIG.  5    is a block diagram illustrating an example of a light fixture with a plurality of temperature sensors within the housing. 
         FIG.  6    is a block diagram illustrating an example of a system comprising a remote computing device operable to determine the status of a plurality of light fixtures. 
         FIG.  7    is a block diagram illustrating an example of a computer system upon which an example embodiment can be implemented. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     This description provides examples not intended to limit the scope of the appended claims. The figures generally indicate the features of the examples, where it is understood and appreciated that like reference numerals are used to refer to like elements. Reference in the specification to “one embodiment” or “an embodiment” or “an example embodiment” means that a particular feature, structure, or characteristic described is included in at least one embodiment described herein and does not imply that the feature, structure, or characteristic is present in all embodiments described herein. 
     Disclosed in an example embodiment herein is an airfield luminaire with sensors employed for determining the status of the light. The airfield light can be any type of airfield luminaire, including but not limited to a Runway centerline light (RCL), runway edge light (REL), e.g., High Intensity Runway Lights (HIRL), Medium Intensity Runway Lights (MIRL), and Low Intensity Runway Lights (LIRL), taxiway centerline light, taxiway edge light, Runway End Identifier Light (REIL), Clearance Bar Lights. Runway Guard lights, Medium-intensity Approach Light with Runway alignment (MALSR), Medium-intensity Approach Light with Sequenced Flashing lights (MALSF), Short Approach Light (SAL), Simplified Short Approach Light (SSAL), Simplified Short Approach Light with Runway Alignment Indicator Lights (SSALR), Simplified Short Approach Lighting System with Sequenced Flashing Light (SSALF), Omni directional Approach Light (ODAL), Lead-in Light (LDIN), Visual Approach Slope Indicator (VASI), Precision Approach Path Indicator (PAPI), Takeoff and Hold light (THL), Touchdown Zone light (TDZL), or a sign. 
     Referring to  FIG.  1   , there is illustrated a simplified functional block diagram illustrating an example a lighting fixture  100  that can be employed as an airfield luminaire. The light fixture  100  comprises a housing  102 , a sensor  104 , a controller  106 , a light source  108 , and a communication interface  110 . 
     The housing  102  can be any desired shape depending on the type of light. In an example embodiment, the housing  102  comprises clear sections (not shown), such as lenses which can be clear or colored, for directing light from the light source  108  outside of the housing  102 . 
     The sensor  104  senses an environmental conditions in the interior  112  of the housing  102 . In example embodiments, the sensor  104  is selected from a group consisting of a combination of a temperature sensor and a pressure sensor for sensing pressure inside the airfield luminaire, a moisture sensor for sensing a leak inside the airfield luminaire, a vibration sensor, an inclinometer, and a magnetic field sensor. 
     A controller  106  comprising logic for performing the functionality described herein is coupled with the sensor  104 . “Logic”, as used herein, includes but is not limited to hardware, firmware, software and/or combinations of each to perform a function(s) or an action(s), and/or to cause a function or action from another component. For example, based on a desired application or need, logic may include a software controlled microprocessor, discrete logic such as an application specific integrated circuit (ASIC), a programmable/programmed logic device, memory device containing instructions, or the like, or combinational logic embodied in hardware. Logic may also be fully implemented in software that is embodied on a tangible, non-transitory computer-readable medium that performs the described functionality when executed by processor. 
     The controller  106  is operable to control the operation of the light source  108 . For example, the controller  106  can control the intensity and/or a flash rate of light from source  108 . 
     Light source  108  can be any suitable type of light source  108 , such as, for example, an incandescent light, halogen light, or a light emitting diode (“LED”). For ease of illustration, it is assumed that the light source  108  includes any associated components that are employed to operate the source of light such as transformers and/or other electronics that provides the appropriate current and/or voltage to the light source  108 . In some embodiments the light source  108  is omni-directional while in other embodiments the light source  108  is directional, such as for example unidirectional or bi-directional. 
     As will be described herein, the controller  106  is operable to determine a status of an airfield luminaire based on data obtained from the sensor  104 . The controller  106  sends data to an external, remote computing system, such as for example, an Airfield Lighting Control &amp; Monitoring System (“ALCMS”) via communication interface  110 . The data sent by the controller  106  via the communication interface  110  can send data representative of the current operational state of the light source  108  (e.g., on/off, blinking, intensity, etc.) and/or as will be described in more detail herein, infra, cause status data determined from data obtained from sensor  104  to be sent to a remote, external computing system (such as for example an ALCMS). In an example embodiment, data from sensor  104  is sent to a remote, external controller via the communication interface  110 . 
     Communication interface  110  can be any type of communication interface for communicating with an external, remote computer system. For example, communication interface  110  can be a wired and/or wireless interface. The communication link (not shown) between the communication interface  110  and an external, remote computing system can be a wired, wireless, or a combination of wired and wireless links. 
     In an example embodiment, the sensor  104  comprises a temperature sensor and a pressure sensor, and the controller  106  can determine if there is a leak in the housing  102  by comparing changes in temperature obtained from a temperature sensor with changes in pressure obtained from a pressure sensor. Because the housing  102  is sealed, a temperature increases or decreases without a corresponding increase or decrease in pressure can indicate a leak in the housing  102 . For example if the temperature increased or decreases by more than ten degrees Celsius without a change in pressure, the controller  106  can determine there is a leak in the housing  102 . In an example embodiment, the ratio of the temperature and pressure is computed and stored by controller  106 . The ratio of temperature and pressure should be constant, so if the controller  106  determines the ratio has been changing over time, or there is a sudden change, by more than a predetermined amount, a leak can be detected. The predetermined amount can be based on a fixed number of degrees (e.g., 10° C.), a percentage change (e.g., 10% or more), and/or based on statistical analysis (e.g., more than 1, 2, or 3 standard deviations). Similarly, a change in pressure without a corresponding change in temperature may also indicate a leak I the housing  102 . If a leak is detected, the controller  106  can take corrective action such as sending a message to an external, remote computing device to report the leak and initiate an inspection and/or repair of the light fixture  100  and/or turning the light fixture  100  off. 
     In another example embodiment, the sensor  104  comprises a moisture sensor and the controller  106  can determine if there is a leak in the housing  102  of the airfield luminaire based on moisture data obtained from the moisture sensor. The moisture sensor can be any type of sensor capable of detecting liquid and/or humidity within the interior  112  of housing  102 . Examples of moisture sensors include, but are not limited to a water sensor and/or a hygrometer. Some embodiments include a combination of a water sensor or a hygrometer. For sensors that detect water, any water detected in the interior  112  of housing  102  can be indicative of a leak. For sensors that detect humidity, the controller  106  may also employ data from a temperature sensor for determining relative humidity. Since the housing  102  is sealed, the moisture content of the interior  112  of the housing  102  should not change, thus a change in temperature without a corresponding change in relative humidity can be indicative of a leak. For example, as temperature increases, the relative humidity should decrease. For example, if the temperature changes by more than ten degrees Celsius without a corresponding change in relative humidity, the controller  106  can determine there is a leak in housing  102 . If a leak is detected, the controller  106  can take corrective action such as sending a message to an external, remote computing device to report the leak and initiate an inspection and/or repair of the light fixture  100  and/or turning the light fixture  100  off. 
     Alternatively, the controller  106  can compute the absolute humidity and/or the specific humidity of the interior  112  of the housing  102  and can determine if there is a leak in housing  102  by detecting changes in the absolute humidity and/or the specific humidity by more than a predetermined amount. The predetermined amount of change for absolute humidity can be a fixed amount (e.g., more than 2 g/cubic meter (g water vapor/cubic meter of air), a fixed percentage (e.g. more than 10%, or a statistically computed amount such as 1, 2, or 3 standard deviations). The predetermined amount of change for specific humidity can be a fixed number, based on a percentage, or based on statistical variations. For example, for specific humidity a change of more than by more 2 g/kg (g air/kg water), or a ten percent change, or a 1, 2, or 3 standard deviation can be indicative of a leak in housing  102 . If a leak is detected, the controller  106  can take corrective action such as sending a message to an external, remote computing device to report the leak and initiate an inspection and/or repair of the light fixture  100  and/or turning the light fixture  100  off. 
     In yet another example embodiment, the sensor  104  is a vibration sensor, such as for example, an accelerometer, such as a piezoelectric accelerometer. The controller  106  can determine structural integrity by comparing a vibration signal obtained from sensor  104  with previously stored vibration signals. For example, the controller  106  can determine the structure integrity of the airfield luminaire based on changes in the vibration signal, such as for example frequency, amplitude (either measured as displacement, acceleration, and/or velocity), or length of time the vibration signal is above a predetermined limit (e.g., 3 dB). The structural integrity of the luminaire can include whether something is loose in the housing  102  (e.g., bolts), support structure (not shown), e.g., an extension, and/or the pavement or the ground (not shown) where the airfield luminaire is mounted. The vibration signal can also differ by the event causing the vibration, for example the peak vibration when a plane passes an airfield luminaire would be greater than the peak vibration when a ground vehicle (e.g., car or maintenance vehicle) passes the airfield luminaire. Thus, the controller  106  can maintain vibration signals for different peaks or ranges of peaks and determine the structural integrity of the airfield luminaire may be deteriorating based on comparing the peak or frequency of a current vibration signal with past signals. For example, deterioration of structural integrity can be determined if the amplitude of vibration signal changes by a predetermined amount (e.g., 2 cm of displacement, 4.9 meters/second/second (or 0.5 g), 16 km/hr,; or a fixed percentage such as ten percent, or a statistical deviation of 1, 2, or 3 standard deviations) and/or the frequency of vibration signal changes by a predetermined amount (such as for example 10 hz, 10%, or a statistical variation of 1, 2, or 3 standard deviations). If the structural integrity is determined to be deteriorating, the controller  106  can take corrective action such as sending a message to an external, remote computing device to report the deterioration of structural integrity and initiate an inspection and/or repair of the light fixture  100  and/or turning the light fixture  100  off. 
     In still yet another example embodiment, the sensor  104  comprises a plurality of temperature sensors located in the interior  112  of the housing  102 . For example, one sensor  104  can be located near the light source  108 , another sensor  104  near the controller  106 , another sensor  104  near power supply  202 , and for example if the light source  108  is an LED, a sensor near the LED and other sensor near the LED electronics. The controller  106  can determine whether there is a malfunction of the airfield luminaire based on a comparison of temperature data from a plurality of temperature sensors associated with the airfield luminaire. For example if one of the temperature sensors is providing a reading that is either higher or lower by a predetermined amount than the rest of the temperature sensors, this can be indicative of a malfunction or failure of a component of the airfield luminaire. For example if the temperature of one of the sensors is more than ten degrees higher, or lower, than the average or mean temperature, or more than ten percent higher, or lower, than the average or mean temperature, and/or the temperature is more than 1, 2, or 3 standard deviations different from mean. Alternatively, kurtosis can be employed to determine if there is an outlier in the temperature measurements. If one or more of the plurality of temperatures is determined to be an outlier when compared to the other temperatures, the controller  106  can take corrective action such as sending a message to an external, remote computing device to report a potential malfunction of the light fixture  100  and initiate an inspection and/or repair of the light fixture  100  and/or turning the light fixture  100  off. 
     In yet another example embodiment, the sensor  104  comprises an inclinometer. The controller  106  is operable to determine a tilt angle for aiming the light source  108 . Based on the tilt angle, the controller  106  is operable to determine if the light source  108  is correctly oriented, which can be very useful for some types of lights, such as for example VASI&#39;s and PAPI&#39;s. For example, for some lighting devices the FAA requires a tilt angle for the light to be within one-quarter degree of the specified tilt angle. If the tilt angle is determined not to be correctly oriented (e.g., outside of a predefined range), then the controller  106  can take corrective action such as sending a message to an external, remote computing device to report an improper tilt angle and initiate an inspection and/or repair of the light fixture  100  and/or turning the light fixture  100  off. 
     In still another example embodiment, the sensor  104  comprises a magnetic orientation sensor that can determine the directional orientation of the light source  108 . For example, the directional orientation of a unidirectional or bidirectional light. The controller  106  is operable to determine whether the directional orientation of the light source  108  is correct based on the data obtained from the magnetic orientation sensor. For example, the controller  106  can determine if the light source  108  of an airfield luminaire is aligned within a predefined limit (e.g., within one degree) of a specified orientation, For example, is the direction of light from the light source  108  in the same direction (or within a specified tolerance such as one degree) as a runway associated with the airfield luminaire. If the controller  106  determines that the magnetic orientation is incorrect (e.g., not within a predetermined range), then the controller  106  can take corrective action such as sending a message to an external, remote computing device to report the deterioration of structural integrity and initiate an inspection and/or repair of the light fixture  100  and/or turning the light fixture  100  off. 
     In an example embodiment, the directional orientation of an airfield luminaire can be compared with a previous measured directional orientation. Changes in the directional orientation of the light can be indicative of a problem with the structural integrity of the airfield luminaire. If the controller  106  determines that directional orientation of the light fixture  100  has changed by more than a predefined amount, then the controller  106  can take corrective action such as sending a message to an external, remote computing device to report the deterioration of structural integrity and initiate an inspection and/or repair of the light fixture  100  and/or turning the light fixture  100  off. 
     In an example embodiment, the controller  106  is operable to determine the remaining life of a light source, such as for example an LED. For example, a factor in the speed at which a LED degrades to the point it needs to be replaced is dependent on the operating temperature, which may be a function on the intensity of the light, the ambient temperature, and the amount of time the light is operated. A LED may need replacement in a few thousand hours or two hundred thousand hours depending on the operating temperature. 
     In an example embodiment, the controller  106  obtains (or is programmed with) data representative of a light output degradation curve based on output temperature and time. Although, the phrase ‘curve’ is used herein, those skilled in the art can readily appreciate that the degradation curve may be linear or substantially linear. 
     The controller  106  obtains temperature measurements from a sensor  104  that is operable to measure the LED operating temperature and the amount of time the LED operates that the measured temperature in real time while the LED is operating (e.g., outputting light). For example, the temperature of the circuit board where the LED is located can be measured. As another example, an infrared (IR) scanner can measure the temperature of the LED. As those skilled in the art can readily appreciate, the temperature of the LED can fluctuate over time. Also, in some embodiments the LED operates at different intensities, which would also result in the LED operating at different temperatures. The controller  106  measures the amount of time the LED was operated at a plurality of temperatures. 
     The controller  106  is operable to determine a present LED light output based on calculating the amount of degradation for a plurality of measured temperatures and a time period operating at the plurality of temperature from the LED aging rate for the plurality of temperatures from an initial light output. For the plurality of operating temperatures, the controller  106  can determine an amount of degradation of the LED for that temperature based on the amount of time the LED was operating at that temperature. The aging rate for temperatures that were not programmed into the controller  106  can be interpolated. The sum of the light output degradation for the plurality of the operating temperatures can be subtracted from the initial light output to obtain the present LED output. In an example embodiment, based on the present LED output, and/or a plurality of previously determined LED light outputs, the controller  106  can determine a rate that the light source  108  is degrading and further provide an estimate on when the light source  108  will need replacing. 
     In an example embodiment, the controller  106  is operable to cause an indication of the present LED light output to be outputted responsive to determining that the present LED light output has achieved a predetermined threshold. For example, the controller  106  can cause a signal to be sent via communication interface  110  to an external, remote controller such as an ALCMS for alerting airfield personnel that the light source  108  should be replaced. In other embodiments, the controller  106  can turn off the light fixture  100  in response to determining the LED has deteriorated beyond a predefined threshold. For example, the FAA requires the light source  108  of an airfield luminaires to be replaced when the light output reaches 70% of its initial output. The ICAO requires the light source  108  of an airfield luminaire to be replaced when the light output reaches 50% of its initial output. 
     In an example embodiment, the determined LED light output can be compared with measured LED light output that measures light from the light source  108 . Light that is measured from the light source  108  can be impacted by factors such as improper aiming of the light or dirt on the lens. Therefore, if the determined LED light output and measured light output differ by more than a predetermined amount (e.g., 2%), the controller  106  can send an alert to check the light for proper alignment and/or dirt on the lens. This may prevent needless replacing of a LED. 
     A LED can become permanently damaged if operated at too high a temperature. In an example embodiment, controller  106  generates an alert if the operating temperature for a LED exceeds a predetermined threshold, such as a manufacturer&#39;s specified operating limit. For example, for an airfield luminaire, the alert can be sent to an external remote computing device such as an ALCMS via communication interface  110 . In particular embodiments, the controller  106  may turn off the light fixture  100  in response to determining the operating temperature of a LED exceeded a predetermined threshold. 
       FIG.  2    is a simplified functional block diagram illustrating an example of a light fixture  300  that can be employed as an airfield luminaire that communicates control signals and/or sensor data over a powerline  202 . The light fixture  300  comprises a power supply  202  operable receive power data signals via the powerline  204 . The power signal is provided to the components within the light fixture  100 , such as for example the light source  108 , controller  106 , and communication interface  110  and depending on the type of sensor, to sensor  104 . As those skilled in the art can readily appreciate, the power supply  202  can provide different levels of voltage and/or current to the light source  108 , controller  106 , communication interface  110 , and if power is being provided, to the sensor  104 . 
     Data signals are provided by the power supply  202  to the communication interface  110  and are processed by the communication interface  110 . In some embodiments, the communication interface  110  is integrated with the power supply  202 . Incoming data signals received from powerline  204  are routed through the power supply  202 , to the communication interface  110  the controller  106 , Data being sent by either the controller  106  or from the sensor  104  are routed through the communication interface  110  to the power supply  202  and the powerline  204 . 
     In an example embodiment, the data signals received from the powerline  204  comprises commands for controlling the operation of the light source  108 . The commands are provided to controller  106  and causes the light source  108  to operate in accordance with the commands. Data signals from the sensor  104  are sent to an external, remote device via the powerline  204 . 
     In an example embodiment, data communication on the powerline  204  is performed in a frequency range using a number of frequency bands within the frequency range. In particular embodiments, Orthogonal Frequency Domain Multiplexing (“OFDM”) is employed for data communication. 
       FIG.  3    is a block diagram illustrating an example of a light fixture  300  with an integrated controller that employs powerline communications and illustrates examples of different types of sensors that can be employed in the light fixture  300 . The types of sensors in the illustrated example comprise a temperature sensor  104 A, a pressure sensor  1048 , a moisture sensor  104 C, a vibration sensor  104 D, an inclinometer  104 E, and magnetic sensor  104 F. As those skilled in the art can readily appreciate, other embodiments may have only a single sensor, or any combination of two, three, or four of the aforementioned embodiments. Other embodiments can include the aforementioned sensors combined with other sensors not listed herein. In the illustrated example, the fixture controller  106  comprises a microprocessor (not shown, see e.g.,  FIG.  5   ) that communicates with the sensors  104 A- 104 F employing an Inter-Integrated Circuit (“I 2 C” or “I2C”) Protocol and employs Pulse Width Modulation (“PWM”) to communicate with and/or power the heater  302  (for those embodiments that have a heater) and the light source  108 . 
     The temperature sensor  104 A can be any suitable type of sensor for measuring temperature within the interior  112  of the housing  102 . As described herein, a temperature sensor can be employed to detect a malfunction, failure, or other problems with a light fixture or a component within the interior  112  of housing  102 . In some embodiments, a combination of measurements from the temperature sensor and the pressure sensor  104 B are employed for detecting leaks in the housing  102 . Examples of temperature sensors  104 A are a thermometer and/or an infra-red (“IR”) sensor. 
     The pressure sensor  104 B can be any suitable sensor for measuring the pressure within the interior  112  of the housing  102 . As described herein, the pressure sensor  104 B can be employed to detect leaks in the housing  102 . Examples of pressure sensors include, but are not limited to, strain gauges, piezoelectric sensors, and/or an aneroid barometer. 
     Moisture sensor  104 C can be any suitable sensor for detecting liquid and/or humidity. As described herein, the moisture sensor can be employed to detect leaks in the housing  102 . In an example embedment, leaks may be detected by the moisture sensor  104 C or, as described herein measurements from the moisture sensor can be combined with can be combined with measurements from the temperature sensor  104 A to detect leaks. Examples of moisture sensors include, but are not limited to a water sensor and/or a hygrometer. 
     The vibration sensor  104 D detects movement of the housing  102 . This can determine whether a component of the housing  102  is loosening, for embodiments employing a mount whether the mount is loosening, and/or whether the surface where the light fixture  500  is deployed is loosening (e.g., pavement or concrete). Any suitable sensor for detecting movement of the housing  102  can be employed, such as for example a piezoelectric sensor. 
     The inclinometer  104 E is aligned with the output (e.g., direction) of the light source  108  and measures the tilt angle for aiming the light source  108 . Certain types of airfield lights such as for example VASI&#39;s and PAPI&#39;s require the light output from the light source  108  be directed at a predefined angle. The inclinometer  104 E can determine whether the light output from the light source  108  is correctly aligned. 
     The magnetic sensor  104 F is aligned with the output (e.g., direction) of the light source  108  and measures the magnetic orientation with respect to the Earth&#39;s magnetic field for aiming the light source  108 . For bi-directional or other multi-directional lights, the magnetic sensor  104 F can be aligned with a selected directional beam. Use of the magnetic sensor  104 F can ensure that the light output from the light source  108  is properly orientated, such as aligned with an associated runway or taxiway. 
     In an example embodiment, the light fixture  500  further comprises a heater  302 . The heater  302  may be employed in airfield luminaires where the light source  108  (such as LED&#39;s) does not generate enough heat to melt ice and snow. 
     The input signal is received on the powerline  204  is provided to the input power supply  202  and the light fixture controller  106 . In an example embodiment, the input power supply  202  is operable to filter out the OFDM signals from the power signal and provides power signal to the light fixture  300 . The light fixture  100  comprises a communication (COMM) filter  304  that filters out the power signal from the data signal received on powerline  204  and provides the data signal to the OFDM transceiver  306 , which provides the data signal to the fixture controller  106 . The controller  106  can process the data signals and send the appropriate commands and/or signals to the light source  108 . 
     The fixture controller  106  can send data signals to an ALCMS via the OFDM transceiver  306 . The OFDM transceiver  306  provides the modulated data signals to the powerline  204  through power supply  202 . 
     In an example embodiment, the controller  106  is operable to process the sensor data received from the sensors  104 A 0 - 104 F, or any other sensor. This can allow for quicker control action in situations that require a faster response than could be provided by a remote controller. In particular embodiments, the controller  106  selectively forwards sensor data from one or more selected sensors through the OFDM transceiver  306 , power supply  202  and powerline  204 . 
       FIG.  4    is a block diagram illustrating an example of a light fixture  400  with an additional wireless communication interface  402  for enabling communication with external portable mobile devices (not shown). Examples of wireless technologies that can be employed by wireless interface  402  can employ include, but are not limited to, BLUETOOTH, Wi-Fi, Near Field Communication (“NFC”), and/or cellular technologies. 
     In an example embodiment, a user with a mobile device can obtain data from sensor  104  via the wireless interface  402 . In another example embodiment, a user can send commands to the controller  106  via the wireless interface  402 . For example, if a user wants to see if the light source  108  is working properly the user can send a command to turn the light on, and if desired specify operating parameters such as intensity and/or blink rate. In still yet another example embodiment, a user with a mobile device can receive sensor data from sensor  104  and send commands to controller  106  via wireless interface  402 . 
       FIG.  5    is a block diagram illustrating an example of a light fixture with a plurality of temperature sensors  104 A within the housing. In an example embodiment, the temperature sensors  104 A can be employed with other sensors  104 . Examples of temperatures that can be measured by the temperature sensors  104 A, include but are not limited to, temperature of the light source  108  or a component within the light source  108  (e.g., LED junction temperature), represented by T 1 , temperature of the controller  106  (e.g., a microprocessor or circuit board associated with controller  106 ) represented by T 2 , the power supply  202  represented by T 3 , in embodiments which have a wireless interface, the wireless interface  402  represented by T 4 , the communication interface  110  represented by T 5 , and the heater  302  represented by 
     T 6 . 
     In an example embodiment, the controller  106 , or other external remote computing device, see e.g., controller  602  in  FIG.  6   , can determine whether there is a malfunction of an airfield luminaire based on a comparison of temperature data (T 1  . . . T 6 ) from a plurality of temperature sensors associated with the airfield luminaire. For example if one of the temperature sensors is providing a reading that is either higher or lower by a predetermined amount than the rest of the temperature sensors, this can be indicative of a malfunction or failure of a component of the airfield luminaire. For example of the temperature of one of the sensors is more than ten degrees higher than the average or mean temperature, or more than ten percent higher than the average or mean temperature, and/or the temperature is more than 1, 2, or 3 standard deviations different from mean. Alternatively, kurtosis can be employed to determine if there is an outlier in the temperature measurements. In an example embodiment, the temperature represented by T 6  can determine whether the heater  302  is functioning properly. 
       FIG.  6    is a block diagram illustrating an example of a system  600  comprising a remote computing device  602  operable to determine the status of a plurality of light fixtures  604 . The controller  602  comprises logic for performing the functionality described herein. In an example embodiment, the controller  602  is an ALCMS. 
     The controller  602  is coupled with a plurality of light fixtures  604  via network  606 . In an example embodiment, the light fixtures  604  are airfield luminaires. The light fixtures  604  can be configured similar to light fixture  100  ( FIG.  1   ), light fixture  200  ( FIG.  2   ), light fixture  300  ( FIG.  3   ), light fixture  400  ( FIG.  4   ) and/or light fixture  500  ( FIG.  5   ). 
     The network  606  can be any suitable type of network. The network  606  may comprise wired, wireless or a combination of wired and wireless links. In an example embodiment, the network  606  is employed for providing both power and data to light fixtures  604  and can provide data from the light fixtures  604  to the controller  602 . 
     As will be described herein, the controller  602  is operable to determine a status of airfield luminaires based on sensor data obtained from the light fixtures  604 . The data sent to the controller  602  can include, but is not limited to, data representative of the current operational state of the light source  108 , within the fixture  604 , (e.g., on/off, blinking, intensity, etc.). 
     In an example embodiment, the controller  602  can determine if there is a leak in the housing  102  of a light fixture  604  by comparing changes in temperature obtained from the light fixture  604  with changes in pressure obtained from the light fixture  604 . A temperature increase or decrease without a corresponding increase or decrease in pressure can indicate a leak in the light fixture  604 . For example if the temperature increases or decreases by more than ten degrees Celsius without a change in pressure, the controller  106  can determine there is a leak in the housing  102 . In an example embodiment, the ratio of the temperature and pressure is computed and stored by controller  106 . The ratio of temperature and pressure should be constant, so if the controller  106  determines the ratio has been changing over time, or there is a sudden change, by more than a predetermined amount, a leak can be detected. The predetermined amount can be based on a fixed number of degrees (e.g., 10° C.), a percentage change (e.g., 10% or more), and/or based on statistical analysis (e.g., more than 1, 2, or 3 standard deviations). In response to detecting a leak, the controller  602  can take corrective action such as reporting the detected leak and/or turning off the light fixture  604  where the leak was detected. 
     In another example embodiment, the sensor data obtained from the light fixture  604  comprises data from a moisture sensor and the controller  602  can determine if there is a leak in one of the plurality of light fixtures  604  based on moisture data obtained from the one of the plurality of light fixture  604 . For light fixtures  604  that employ sensors that detect water, any water detected in the interior the light fixture  604  can be indicative of a leak. For light fixtures  604  that employ sensors that detect humidity, the controller  602  may also employ data from a temperature sensor for determining relative humidity. The amount of moisture within a light fixture  604  should remain constant, thus a change in temperature without a corresponding change in relative humidity can be indicative of a leak. For example, as temperature increases, the relative humidity should decrease. For example, if the temperature changes by more than ten degrees Celsius without a corresponding change in relative humidity, the controller  106  can determine there is a leak in housing  102 . In response to detecting a leak, the controller  602  can take corrective action such as reporting the detected leak and/or turning off the light fixture  604  where the leak was detected. 
     Alternatively, the controller  602  can compute the absolute humidity and/or the specific humidity for the light fixtures  604  and can determine if there is a leak in one of the plurality of light fixtures  604  by detecting changes in the absolute humidity and/or the specific humidity by more than a predetermined amount. The predetermined amount of change for absolute humidity can be a fixed amount (e.g., more than 2 g/cubic meter (g water vapor/cubic meter of air), a fixed percentage (e.g. more than 10%, or a statistically computed amount such as 1, 2, or 3 standard deviations). The predetermined amount of change for specific humidity can be a fixed number, based on a percentage, or based on statistical variations. For example, for specific humidity a change of more than by more 2 g/kg (g air/kg water), or a ten percent change, or a 1, 2, or 3 standard deviation can be indicative of a leak in housing  102 . In response to detecting a leak, the controller  602  can take corrective action such as reporting the detected leak and/or turning off the light fixture  604  where the leak was detected. 
     In yet another example embodiment, controller  602  obtains data from a vibration sensor from at least one of the plurality of light fixture  604 . The controller  602  can determine structural integrity of any of the plurality of light fixtures  604  by comparing a vibration signal obtained previously stored vibration signals for that light fixture. For example, the controller  602  can determine the structure integrity of any of plurality of light fixture  604  based on changes in the vibration signal, such as for example frequency, amplitude (either measured as displacement, acceleration, and/or velocity), or length of time the vibration signal is above a predetermined limit (e.g., 3 dB). The structural integrity of the light fixtures  604  can include whether something is loose in the housing (e.g., housing  102  in  FIGS.  1 - 5   ), such as bolts, the support structure, e.g., an extension, and/or the pavement or the ground where the light fixtures are mounted. The vibration signal can also differ by the event causing the vibration, for example the peak vibration when a plane passes an airfield luminaire would be greater than the peak vibration when a ground vehicle (e.g., car or maintenance vehicle) passes the airfield luminaire. Thus, the controller  602  can maintain vibration signals for different peaks or ranges of peaks and determine whether the structural integrity the light fixture  604  may be deteriorating based on comparing the peak or frequency of a current vibration signal with past signals. For example, deterioration of structural integrity can be determined if the amplitude of vibration signal changes by a predetermined amount (e.g., 2 cm of displacement, 4.9 meters/second/second (or 0.5 g), 16 km/hr,; or a fixed percentage such as ten percent, or a statistical deviation of 1, 2, or 3 standard deviations) and/or the frequency of vibration signal changes by a predetermined amount (such as for example 10 hz, 10%, or a statistical variation of 1, 2, or 3 standard deviations). In response to detecting the deterioration of a light fixture  604 , the controller  602  can take corrective action such as reporting the detected problem with the structural integrity and/or turning off the light fixture  604  where the deterioration was detected. 
     In an example embodiment, the controller  602  can obtain vibration data from the plurality of light fixtures  604  and determine whether structural integrity of one of the plurality of light fixtures  604  is deteriorating by comparing the vibration data obtained from the plurality of light fixtures  604 . For example, deterioration of structural integrity can be determined if the amplitude of vibration signal from one of the plurality of light fixtures  604  differs from the other light fixtures by a predetermined amount (e.g.,  2 cm of displacement, 4.9 meters/second/second (or 0.5 g), 16 km/hr,; or a fixed percentage such as ten percent, or a statistical deviation of 1, 2, or 3 standard deviations) and/or the frequency of vibration signal changes by a predetermined amount (such as for example 10 hz, 10%, or a statistical variation of 1, 2, or 3 standard deviations). In an example embodiment, kurtosis can be employed to detect and identify outliers. If the controller  106  determines that structural integrity of one or more of the vibration signals from the plurality of light fixtures is different by the predetermined amount, then the controller  106  can take corrective action such as sending a message to an external, remote computing device to report the deterioration of structural integrity and initiate an inspection and/or repair of the light fixture  604  and/or turning the light fixture  604  off. 
     In still yet another example embodiment, the sensor data obtained from the plurality of light fixtures  604  comprises a plurality of temperature sensors located within the plurality of light fixtures  604 , controller  602  can determine whether there is a malfunction of the airfield luminaire based on a comparison of temperature data from a plurality of temperature sensors associated with the airfield luminaire. For example if one of the temperature sensors is providing a reading that is either higher or lower by a predetermined amount than the rest of the temperature sensors, this can be indicative of a malfunction or failure of a component of the airfield luminaire. For example if the temperature of one of the sensors is more than ten degrees higher than the average or mean temperature, or more than ten percent higher than the average or mean temperature, and/or the temperature is more than 1, 2, or 3 standard deviations different from mean. Alternatively, kurtosis can be employed to determine if there is an outlier in the temperature measurements. If the controller  602  determines a potential malfunction based on the comparison of temperature data for the plurality of light fixtures, the controller  106  can take corrective action such as sending a message to an external, remote computing device to report the potential malfunction of the one or more light fixtures  604  and initiate an inspection and/or repair of the light fixture  604  and/or turning the one or more of the plurality of light fixtures  604  off. 
     In yet another example embodiment, the sensor data that the controller  602  receives from the plurality of light fixtures  604  comprises a tilt angle from an inclinometer. Based on the tilt angle, the controller  602  is operable to determine if the light source is correctly oriented, which can be very useful for some types of lights, such as for example VASI&#39;s and PAPI&#39;s. For example, for some lighting devices the FAA requires a tilt angle for the light to be within one-quarter degree of the specified tilt angle. Upon detecting that one or more of the plurality of light fixtures  604  is misaligned, the controller  602  can take other corrective actions such as shutting off the light fixture  604  that is misaligned, shutting of the plurality of light fixtures  604 . In particular embodiments, the controller  602  generates a Notice to Airmen (“NOTAM”) upon detecting a misaligned light fixture  604 . 
     In still another example embodiment, the sensor data obtained from the plurality of light fixtures  604  comprises the magnetic orientation for the plurality light fixtures  604 . For example, the directional orientation of a unidirectional or bidirectional light. The controller  602  is operable to determine whether the directional orientation of any of the plurality of light fixtures  604  is correct based on the data obtained from the magnetic orientation sensor. For example, the controller  602  can determine if a light fixture  604  is aligned within a predefined limit (e.g., within one degree) of a specified orientation, For example, the controller  602  can determine if the direction of light from a light fixtures  604  is in the same direction (or within a specified tolerance such as one degree) as a runway associated with the light fixture  604 . 
     In an example embodiment, controller  602  compares the directional orientation of any of the plurality of light fixtures  604  with a previous measured directional orientation. Changes in the directional orientation of a light fixture  604  can be indicative of a problem with the structural integrity of the airfield luminaire. 
     In an example embodiment, the controller  602  is operable to determine the remaining life of a light source, such as for example an LED for the plurality of light fixtures  604 . A LED may need replacement in a few thousand hours or two hundred thousand hours depending on the operating temperature. 
     In an example embodiment, the controller  602  obtains (or is programmed with) data representative of a light output degradation curve for individual light fixtures selected from the plurality of light fixtures  604  based on output temperature and time. Although, the phrase ‘curve’ is used herein, those skilled in the art can readily appreciate that the degradation curve may be linear or substantially linear. 
     The controller  602  obtains the LED operating temperature and the amount of time the LED operates for any one or all of the plurality of light fixtures  604 . As those skilled in the art can readily appreciate, the temperature of the LED can fluctuate over time. Also, in some embodiments (such as airfield luminaires), the LED operates at different intensities, which would also result in the LED operating at different temperatures. The controller  602  measures the amount of time the LED was operated at the plurality of temperatures. 
     The controller  602  is operable to determine a present LED light output of a light fixture  604  based on calculating the amount of degradation for a plurality of measured temperatures and a time period operating at a plurality of temperatures from the LED aging rate for the plurality of temperatures from an initial light output. For the plurality of operating temperatures, the controller  602  determines an amount of degradation of the LED for that temperature based on the amount of time the LED was operating at that temperature. The aging rate for temperatures that were not programmed into the controller  602  can be interpolated. The sum of the light output degradation for the plurality of operating temperatures can be subtracted from the initial light output to obtain the present LED output. In an example embodiment, based on the present LED output, and/or a plurality of previously determined LED light outputs, the controller  602  can determine a rate that the light source for a light fixture is degrading and further provide an estimate on when the light source for the light fixture  604  will need replacing. 
     In an example embodiment, the controller  602  is operable to cause an indication of the present LED light output to be outputted responsive to determining that the present LED light output has achieved a predetermined threshold. For example, the controller  602  can cause an alert to be provided to airfield personnel that the light source of a light fixture  608  should be replaced. For example, the FAA requires the light source of an airfield luminaires to be replaced when the light output reaches  70 % of its initial output. The ICAO requires the light source  108  of an airfield luminaire to be replaced when the light output reaches  50 % of its initial output. 
     In an example embodiment, the determined LED light output for a light fixture  604  can be compared with measured light output that measures light output from the light fixture  604 . Light output that is measured from the light source  108  can be impacted by factors such as improper aiming of the light and/or dirt on the lens. Therefore, if the determined LED light output and measured light output differ by more than a predetermined amount (e.g., 2%), the controller  602  can cause an alert to check the light for proper alignment and/or dirt on the lens. This may prevent needless replacing of a LED for a light fixture  604 . 
     In an example embodiment, the controller  602  can take other corrective action if one or more (or all) of the plurality of light fixture&#39;s output has dropped below the predetermined threshold. For example, the controller  602  can shut off the light fixture that is below the threshold, a group of lights associated with a light fixture  604  that is below the threshold, or all of the light fixtures  604 . In particular embodiments, the controller  602  can generate a NOTAM. 
     Although the example illustrated in  FIG.  6    employs light fixtures, such as airfield luminaires, those skilled in the art can readily appreciate the illustrated embodiments were selected merely for ease of illustration and that the principles described in the example embodiments described herein can be employed to obtain sensor data from any suitable type of devices with communication capabilities, Therefore, the description herein should not be construed as limited to airfield luminaires. 
       FIG.  7    is a block diagram of a computer system  700  upon which an example embodiment can be implemented. Computer system  700  can be employed to implement the controller  106  ( FIGS.  1 - 5   ) and/or the controller  602  ( FIG.  6   ). 
     Computer system  700  includes a bus  702  or other communication mechanism for communicating information and a processor  704  coupled with bus  702  for processing information. Computer system  700  also includes a main memory  706 , such as random access memory (RAM) or other dynamic storage device coupled to bus  702  for storing information and instructions to be executed by processor  704 . Main memory  706  also may be used for storing a temporary variable or other intermediate information during execution of instructions to be executed by processor  704 . Computer system  700  further includes a read only memory (ROM)  708  or other static storage device coupled to bus  702  for storing static information and instructions for processor  704 . A storage device  710 , such as a magnetic disk or optical disk, is provided and coupled to bus  702  for storing information and instructions. 
     An aspect of an example embodiment is related to the use of computer system  700  for an Airfield Ground Light with Integrated Light Controller That Employs Powerline Communications and Sensors. According to one embodiment, operation of the Airfield Ground Light with Integrated Light Controller That Employs Powerline Communications and Sensors is provided by computer system  700  in response to processor  704  executing one or more sequences of one or more instructions contained in main memory  706 . Such instructions may be read into main memory  706  from another computer-readable medium, such as storage device  710 . Execution of the sequence of instructions contained in main memory  706  causes processor  704  to perform the process steps described herein. One or more processors in a multi-processing arrangement may also be employed to execute the sequences of instructions contained in main memory  706 . In alternative embodiments, hard-wired circuitry may be used in place of or in combination with software instructions to implement an example embodiment. Thus, embodiments described herein are not limited to any specific combination of hardware circuitry and software. 
     The term “computer-readable medium” as used herein refers to any medium that participates in providing instructions to processor  704  for execution. Such a medium may take many forms, including but not limited to non-volatile media. Non-volatile media include for example optical or magnetic disks, such as storage device  710 . Common forms of computer-readable media include for example RAM, PROM, EPROM, FLASHPROM, CD, DVD, SSD or any other memory chip or cartridge, or other medium from which a computer can read. 
     Computer system  700  also includes a communication interface  718  coupled to bus  702 . Communication interface  718  provides a two-way data communication coupling to a network link  720  that is connected to a network (not shown, see e.g., network  606  in  FIG.  6   ). For example, communication interface  718  may be an integrated services digital network (ISDN) card or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface  718  may be a local area network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, communication interface  718  sends and receives electrical, electromagnetic, or optical signals that carry digital data streams representing various types of information. 
     Communication link  720  typically provides data communication through one or more networks to other data devices. For example, communication link  720  can provide communications to the sensors or other components described herein. 
     Described above are example embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies, but one of ordinary skill in the art will recognize that many further combinations and permutations of the example embodiments are possible. Accordingly, this application is intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.