LUMINAIRE ASSOCIATE STATUS TRANSPONDER

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

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.

Occasionally a street lighting asset, in particular a luminaire associate, will be relocated without appropriately noting the asset's relocation in the infrastructure'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.

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

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

FIG. 1 illustrates the segmentation of a lighting fixture according to one embodiment.

FIG. 2 illustrates a linear installation of lighting fixtures according to one embodiment.

FIG. 3 illustrates a more topographically complex installation of lighting fixtures according to one embodiment.

FIG. 4 illustrates adding an additional interrogator unit according to one embodiment.

DETAILED DESCRIPTION

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.

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.

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.

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.

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.

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

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.

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's distance to the seven lighting fixtures is discovered and displayed in Table 2.

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

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.

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.

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

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.

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.

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.

As presented, the distance between an interrogating unit and a transponder is estimated by the interrogating unit'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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Claims

1. A method for interrogating transponders located within devices at distinct locations on a powerline commonly connected to the addressable transponders comprising the steps of: transmitting an interrogation signal by at least one interrogation device on the powerline, the interrogation signal being addressed to an addressable transponder;receiving a response signal on the powerline from the addressable transponder;electronically measuring a time period between receiving the response signal and transmitting the interrogation signal; andelectronically estimating a distance to the addressable transponder by using the time period measured to receive the response signal.

2. The method of claim 1 further comprising the step of using pulse compression signaling for generation of the interrogation and the response signals.

3. The method of claim 1 wherein the addressable transponder is located in a luminaire associate or in a fixed reference responder.

4. The method of claim 3 wherein the step of electronically estimating further comprises using the electronically measured time to receive a response from the fixed reference responder to improve the estimation of distance.

5. The method of claim 3 further comprising the step of electronically deriving status of the luminaire associate by further processing the received response by the at least one interrogation device.

6. The method of claim 3 further comprising the step of forwarding the estimated distance of a particular luminaire associate from the one or more interrogation devices to a lighting control system operations center.

7. The method of claim 3 further comprising the step of forwarding the electronically derived status of the luminaire associate by the interrogation devices to a lighting control system operations center.

8. A system for electronically estimating the distance between a powerline interrogator and an addressable transponder both connected to a common powerline comprising: an interrogation signal generator within the powerline interrogator that generates and transmits an interrogation signal addressed to the addressable transponder;a receiver within the addressable transponder that recognizes the interrogation signal addressed to the addressable transponder;a transmitter within the addressable transponder that sends a response to the powerline interrogator after recognizing receipt of the interrogation signal addressed to the addressable transponder;an electronic timer within the powerline interrogator to measure the time required to receive the response from the addressable transponder; andan electronic calculator within the powerline interrogator to estimate the distance to the addressable transponder by using the measured time required to receive the response.

9. The system of claim 8 wherein the addressable transponder is located in a luminaire associate or in a fixed reference responder.

10. The system of claim 9 wherein the powerline interrogator electronically derives the status of the luminaire associate by further processing the response received from the addressable transponder located in the luminaire associate.

11. The system of claim 9 wherein the electronically measured time to receive a response from the fixed reference responder is used to validate or improve estimation of distance.

12. The system of claim 9 wherein the estimated distance to the addressable transponder in a luminaire associate is forwarded to a lighting control system operations center.

13. The system of claim 12 wherein the status of the luminaire associate is forwarded to the lighting control system operations center.

14. A system for interrogating transponders on a common powerline comprising: a first device that generates and transmits an interrogation signal on the common powerline, the interrogation signal addressed to a transponder; anda second device containing a transponder that shares the common powerline and generates a response to the interrogation signal and places the response on the common powerline.

15. The system of claim 14 wherein the first device uses pulse compression signaling.

16. The system of claim 15 wherein the second device is selected from: a particular luminaire associate out of a plurality of luminaire associates; or another device that has a known fixed location that generates and transmits interrogation signals.

17. The system of claim 16 wherein the second device uses pulse compression signaling.

18. The system of claim 17 further comprising: a computational element operatively coupled to the first device;a receiver operatively coupled to the first device that receives the response from the common powerline;a timer associated with the first device that measures a time period between receiving the response of and transmitting the interrogation signal; anda calculator associated with the first device to estimate a distance between the first device and the second device using the time period.

19. The system of claim 16 wherein the second device is located in a luminaire associate that exists with a unique address within a plurality of luminaire associates.

20. The system of claim 19 further comprising the response including an electronically derived status of the luminaire associate.