Abstract:
Monitoring street lighting infrastructure using special signaling devices and techniques for locating key components of the infrastructure and assessing their status. The integrity of common powerline connections may also be assessed.

Description:
BACKGROUND 
       [0001]    This application is a non-provisional of and claims the benefit of U.S. Provisional Patent Applications Ser. Nos. 61/907,069, 61/907,078, 61/907,090, 61/907,114, 61/907,133, 61/907,150, 61/907,168, 61/907,188 and 61/907,210 filed on Nov. 21, 2013, the entire contents of which are incorporated herein by reference. 
     
    
       [0002]    The ability to quickly discover the location and health and operational status of individual street lamps is important to many infrastructure owners and operators. Many urban utilities have come to rely on databases for recording the locations of their lighting control system assets, in particular the individual luminaires and the controls and connections, the luminaire associates, which interface the luminaires with the powerline. These data bases help the infrastructure owners and operators manage their operations including street lighting augmentation, maintenance, asset relocation, and control. Other functions that depend on knowing the accurate location of individual street lamps include billing and inventory and maintenance recordation. 
         [0003]    Occasionally a street lighting asset, in particular a luminaire associate, will be relocated without appropriately noting the asset&#39;s relocation in the infrastructure&#39;s database. This omission may lead to a variety of problems including costly maintenance crew searches for the relocated asset. There is therefore a need for detecting that a luminaire associate has been relocated and to determine its new location in the lighting system. 
         [0004]    Issues that may affect the infrastructure of lighting systems include the timely notification of existing, or developing, health or operational problems with individual luminaires and their respective luminaire associates. In some cases, maintenance crews need to drive to or near luminaires to check on their status. The dispatch of maintenance crews for this purpose is costly and time consuming and becomes ever more so as the lighting system is expanded. There is therefore a need to instantiate a technique whereby the infrastructure owner and operator can more quickly determine existing or developing health or operational problems with individual luminaire associates with less involvement of maintenance crews. 
       SUMMARY 
       [0005]    An interrogation device is provided that is configured to send interrogation signals to one or more addressable transponders using a common powerline for transmissions. The distance between the interrogating device and the addressable transponder is determined by measuring the time to receive a response from the addressable transponder following its interrogation. The interrogation and response signaling are carried on the common powerline. 
     
    
     
       BRIEF DESCRIPTION OF ILLUSTRATIONS 
         [0006]      FIG. 1  illustrates the segmentation of a lighting fixture according to one embodiment. 
           [0007]      FIG. 2  illustrates a linear installation of lighting fixtures according to one embodiment. 
           [0008]      FIG. 3  illustrates a more topographically complex installation of lighting fixtures according to one embodiment. 
           [0009]      FIG. 4  illustrates adding an additional interrogator unit according to one embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0010]    The location and health and operational status of individual street lamps is important to many infrastructure owners and operators. Many urban utilities rely on databases maintained by their lighting control system operations center for recording the locations of their lighting control system assets. These assets may include individual luminaires and their luminaire associates. Luminaire associates comprise controls and connections that interface with the luminaires with the powerline. These databases help the infrastructure owners and operators manage their operations. These operations include planning for street lighting augmentation, maintenance, asset relocation, and controls. Other functions that depend on knowing the accurate location of individual street lamps include billing, inventory auditing, and maintenance recordation. This application teaches a method, system, and devices for aiding the lighting control system operations center in keeping its databases current and correct. 
         [0011]    An embodiment of the invention is illustrated in  FIG. 1 . The lighting fixture  100  comprises a lamp or luminaire  110 , supported by a luminaire associate  120 . The luminaire associate  120  comprises electronic components, electrical circuitry, and mechanical couplings associated with the mounting and control of the luminaire  110 . The luminaire associate  120  may be mounted atop a pole  130  that also provides a conduit for the powerline  140  serving the luminaire associate  120  and the luminaire  110 . 
         [0012]    In one embodiment, one or more interrogation devices are coupled to the powerline  140  that is common to a plurality of individual lighting fixture  100 . An interrogation signal is placed on the powerline  140  by an interrogator device and travels to an addressed transponder. The lighting fixtures  100  may contain addressable transponders. The transponder that is addressed transponds by placing a response signal on the powerline  140 . The interrogator device measures the time to receive the response signal and estimates the distance from the interrogator to the transponder. 
         [0013]    Although the speed of signal propagation on the powerline  140  is a significant fraction of the speed of light in free space, the speed of signal propagation on the powerline is dependent on many parameters. It may be therefore advisable to occasionally measure the speed of signal propagation on the powerline  140  in order to validate or improve the estimation of distance. This may be done in several ways. By way of example, this may be done by measuring the time it takes after an interrogator unit sends the interrogation signal until and a response is received by a fixed reference transponder, a transponder whose position is known and invariant. Then that time is divided by two because of the round trip time of signal propagation. 
         [0014]      FIG. 2  illustrates a linear installation of lighting fixtures  201 - 205  each configured similarly to lighting fixture  100  discussed in relation to  FIG. 1 . Lighting fixtures  201 - 205  are connected to a common powerline  140  along with an interrogation unit  210 . The interrogation unit  210  contains computational hardware and software used in signal generation, transmission, reception and decoding. Also illustrated in connected to common powerline  140  is a fixed reference responder  211 . The interrogator unit  210  places an interrogation signal on the power line  140  that is uniquely addressed to a transponder contained in either the fixed reference responder  211  or one of the luminaire associates  120 . The addressed transponder responds to the interrogator unit  210 . The addressed transponder may be a particular one of the luminaire associates  120  within lighting fixtures  201 - 205 . The interrogator unit  210  measures the time duration between sending an interrogation signal to a particular luminaire associate and receiving the receiving the response signal from that particular luminaire associate. The interrogator may calculate the distance to the particular luminaire associate. In this manner, the interrogator unit  210  can discover the distances to the five lighting fixture  201 - 205  as displayed in Table 1. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Lighting fixture distances to interrogator unit 210 
               
             
          
           
               
                   
                   
                 Distance to 
               
               
                   
                 Lighting 
                 interrogator unit 
               
               
                   
                 Fixture 
                 210 
               
               
                   
                   
               
               
                   
                 201 
                 1 
               
               
                   
                 202 
                 2 
               
               
                   
                 203 
                 3 
               
               
                   
                 204 
                 4 
               
               
                   
                 205 
                 5 
               
               
                   
                   
               
             
          
         
       
     
         [0015]    The distances in Table 1 are all distinct and because the installation of lighting fixtures is linear and spacing of street lights substantially similar as depicted in  FIG. 2 , the positions of the individual lighting fixtures in the linear installation is unambiguously determinable. 
         [0016]    More complex scenarios are expected in practice, such as that illustrated in  FIG. 3 . In  FIG. 3  there is a power line branch  141  connected to power line  140 . There are two lighting fixtures,  206  and  207 , on power line branch  141 . In the example illustrated in  FIG. 3  the interrogation unit&#39;s distance to the seven lighting fixtures is discovered and displayed in Table 2. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Lighting fixture distances to interrogator unit 210 
               
             
          
           
               
                   
                   
                 Distance to 
               
               
                   
                 Lighting 
                 interrogator unit 
               
               
                   
                 Fixture 
                 210 
               
               
                   
                   
               
               
                   
                 201 
                 1 
               
               
                   
                 202 
                 2 
               
               
                   
                 203 
                 3 
               
               
                   
                 204 
                 4 
               
               
                   
                 205 
                 5 
               
               
                   
                 206 
                 4 
               
               
                   
                 207 
                 5 
               
               
                   
                   
               
             
          
         
       
     
         [0017]    As seen in Table 2, the various lighting fixture distances to the interrogator unit  210  are not distinct. The pair of lighting fixtures  204  and  206 , and the pair of lighting fixtures  205  and  207 , exhibit identical distances to the interrogator unit  210 . Thus lighting fixture  204  could have been swapped with lighting fixture  206  or lighting fixture  205  could have been swapped with lighting fixture  207  without provoking a difference in the values displayed in Table 2. The lighting fixture positions are therefore not uniquely discoverable on the lighting fixture layout illustrated in  FIG. 3  solely by the information in Table 2. 
         [0018]    The individual lighting fixture positions may be made uniquely discoverable by using a plurality of interrogator units positioned at different points on the common powerline.  FIG. 4  illustrates an additional interrogator unit  220  with connection to the power line branch  141  by the conductor  142 . For the lighting fixture layout example illustrated in  FIGS. 3 and 4 , the distances from two interrogator units  210 ,  220  to the seven lighting fixtures is displayed in Table 3. 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Lighting fixture distances to interrogator units 210 and 220 
               
             
          
           
               
                   
                 Distance to 
                 Distance to 
               
               
                 Lighting 
                 interrogator unit 
                 interrogator 
               
               
                 Fixture 
                 210 
                 unit 220 
               
               
                   
               
               
                 201 
                 1 
                 5 
               
               
                 202 
                 2 
                 4 
               
               
                 203 
                 3 
                 5 
               
               
                 204 
                 4 
                 6 
               
               
                 205 
                 5 
                 7 
               
               
                 206 
                 4 
                 2 
               
               
                 207 
                 5 
                 1 
               
               
                   
               
             
          
         
       
     
         [0019]    The pairs of individual lighting fixture distances to the two position interrogator units  210 ,  220  are all unique and, therefore, the individual lighting fixture positions on the lighting fixture layout illustrated in  FIGS. 3 and 4  are uniquely discoverable. 
         [0020]    In general, the individual lighting fixture positions may be made uniquely discoverable by using P interrogator units connected to the powerline at various points so that each P-tuple value of the lighting fixture distances from each position interrogator unit to each of the lighting fixtures on the common powerline are unique. 
         [0021]    In addition to estimating distances on the powerline  140 , the response of a transponder located in a luminaire associate  120  of a lighting fixture may also report on the status of the of the luminaire  110  and the luminaire associate  120  of that lighting fixture. One embodiment of this technique is to append the status information to the transponder response signal. The status of a luminaire associate  120  may comprise data reporting on operationally important luminaire electrical parameters such as voltage, current, wattage, and real power, and other data including data characterizing the output of luminaire  110 . The status may also include a condition status placed in the luminaire associate  120  by a maintenance crew reporting on servicing details. 
         [0022]    As presented, the distance between an interrogating unit and a transponder is estimated by the interrogating unit&#39;s sending an interrogation signal though a communication medium to the transponder. The transponder responds upon reception of the interrogation signal. The interrogating unit receives the transponder signal and uses the round trip time from interrogation signal transmission to reception of transponder response and the speed of signal propagation through the communication medium to estimate the distance between them. The accuracy of the estimated distance is dependent on the time-bandwidth characteristic of the signaling waveforms used by the interrogator and the transponder. 
         [0023]    For an example relevant to this application, the distance of an interrogating unit to a transponder via a common powerline  140  may be estimated using signaling waveforms of sufficient time-bandwidth. A problem with using a short-time very high bandwidth signal is that the powerline may not be capable of supporting signaling that has a very high bandwidth. Pulse compression signaling may be used to obviate this limitation. 
         [0024]    Pulse compression is a technique well known in the art of signal design whereby a signal may be crafted to achieve a large time-bandwidth product by increasing the signaling time with concomitant maintenance of bandwidth. For an example, a basic signal s(t) of period T-time units that has a power spectrum whose maximum significant frequency is at or below the maximum frequency that the powerline will support for signaling purposes. A common technique is to build a signal s(t) by choosing a T-time units long segment of a sine wave having many periods. The signal s(t) is then multiplied by a sequence of plus and minus ones such that an autocorrelation is created characterized by a sharp spike around the zero-offset point of the autocorrelation and low magnitude sidelobes. The sequence of plus and minus ones and the segment of the sine wave of many periods may be aligned so that transition times of the sequence of plus and minus ones align with zero crossings of the segment of the sine wave of many periods. 
         [0025]    The interrogation signal formed for this example may be built by concatenating one or more periods of s(t) followed by one period of s(t) inverted, denoted as  s (t), followed by N periods, each of length T-time units, and each period comprising either s(t) or  s (t). Signaling in this manner allows an addressable transponder to: recognize, by the reception of one or more s(t) basic signals, that an interrogation message has begun; then note, by the first occurrence of  s (t), that the address of the addressable transponder is to follow by the next N periods of s(t) and  s (t); and then derive the address of the addressed transponder by decoding an occurrence of s(t) as a zero and an occurrence of  s (t) as a one. 
         [0026]    The addressed transponder then responds with a signal built by concatenating one or more periods of s(t) followed by one period of s(t) inverted, denoted as  s (t), followed by N periods, each of length T-time units, and each period consisting of s(t). This example signaling format may also appear as an interrogator unit addressing a transponder with an address of all zeros. Embodiments are envisioned that avoid this ambiguity by not allowing any transponder to be assigned an address of all zeros. 
         [0027]    If the addressed transponder is located in a fixed reference responder  211 , the fixed reference transponder  211  ceases transponding after sending the above response as the fixed reference transponder  211  will not be reporting status. If the addressed transponder is located in a luminaire associate  120 , the addressed transponder continues the above transmission by concatenating M periods, each of length T-time units, and each period comprising either s(t) or  s (t). These M bits inform the interrogator of one of 2 M  conditions reportable by the luminaire associate where the addressed transponder is located. 
         [0028]    In an embodiment, more than one interrogation units  210  are connected to the common powerline  140 . A signaling protocol may be instituted to prevent any interrogation signaling and the responses that are generated from overlapping. There are many suitable candidate protocols known in the art including transmission sensing, collision avoidance, and non-overlapping time-based slots, with guard times as prudent, assigned to each interrogator unit. 
         [0029]    Data respecting the distances for the lighting fixture to interrogator units that are discovered and status information reported by transponders located in luminaire associates are forwarded to the lighting control system operations center. 
         [0030]    An exemplary technical effect of the methods and systems described herein includes: (a) generating a melt pool based on the build parameters of the component; (b) detecting an optical signal generated by the melt pool to measure the size or the temperature of the melt pool; and (c) modifying the build parameters in real-time based on the size or the temperature of the melt pool to achieve a desired physical property of the component. 
         [0031]    Some embodiments involve the use of one or more electronic or computing devices. Such devices typically include a processor or controller, such as, without limitation, a general purpose central processing unit (CPU), a graphics processing unit (GPU), a microcontroller, a field programmable gate array (FPGA), a reduced instruction set computer (RISC) processor, an application specific integrated circuit (ASIC), a programmable logic circuit (PLC), and/or any other circuit or processor capable of executing the functions described herein. 
         [0032]    The methods described herein may be encoded as executable instructions embodied in a computer readable medium, including, without limitation, a storage device, and/or a memory device. Such instructions, when executed by a processor, cause the processor to perform at least a portion of the methods described herein. The above examples are exemplary only, and thus are not intended to limit in any way the definition and/or meaning of the term processor. 
         [0033]    Exemplary embodiments for enhancing the build parameters for making additive manufactured components are described above in detail. The apparatus, systems, and methods are not limited to the specific embodiments described herein, but rather, operations of the methods and components of the systems may be utilized independently and separately from other operations or components described herein. For example, the systems, methods, and apparatus described herein may have other industrial or consumer applications and are not limited to practice with electronic components as described herein. Rather, one or more embodiments may be implemented and utilized in connection with other industries. 
         [0034]    Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced or claimed in combination with any feature of any other drawing. 
         [0035]    This written description uses examples to disclose the invention, including the best mode, and to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.