Optical-based fire detection system and method

Abstract

To provide an optical fire detection system and a method that prevent false detection of fire occurrence.SOLUTION: An optical-based fire detection system includes an optical signal collection unit positioned inside a combustible area, an optical signal processing unit positioned outside the combustible area, one or more optical fiber bundles optically interconnecting an optical signal calibration unit, a collection unit, a processing unit and a calibration unit. In a fire detection mode, a combustible area is monitored for the occurrence of a fire in the combustible area, and the optical signal processing unit receives an optical signal from the collection unit and one or more characteristics of the optical signal are processed to determine whether the optical signal indicates a fire in the combustible area. In a system calibration mode which verifies the functionality of the fire detection system, the optical signal processing unit receives a calibration optical signal from the optical signal collection unit and processes the calibration optical signal.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] FIELD OF THE INVENTION This application relates to fire detection systems, and more particularly to optical-based fire detection systems and methods. [Background technology]

[0002] Fire detection systems that employ eutectic wires are known. In this type of fire detection system, the eutectic wire melts due to the flames of a fire, indicating the occurrence of a fire. A drawback of using this type of fire detection system is that the eutectic wire is a one-time use item. Therefore, a typical fire detection system can only be used once. Another drawback is that when the eutectic wire melts, the location of the fire is not identified.

[0003] Fire detection systems employing optical fire detectors are also known. In this type of fire detection system, the optical fire detector receives light from a fire flame. This light is processed to provide a signal indicative of the occurrence of a fire. A drawback to using this type of fire detection system is that the system may be unable to distinguish between light from an actual fire and light from background light emissions. Therefore, typical fire detection systems employing optical fire detectors may falsely detect an occurrence of a fire. Another drawback is that the calibration of fire detection systems, including optical fire detectors, may become out of sync over time. As a result, the fire detection system may not indicate the occurrence of a fire when an actual fire occurs. It is desirable to overcome the drawbacks of known fire detection systems, including optical-based fire detection systems. Summary of the Invention

[0004] In one aspect, a method of operating an optical-based fire detection system is provided. The method includes monitoring a combustible region for the occurrence of a fire in the combustible region. The method also includes collecting light emitted from the combustible region. The method further includes directing the collected light to an optical signal processing unit positioned outside the combustible region. The method further includes processing the collected light in the optical signal processing unit positioned outside the combustible region to determine whether the collected light is indicative of a fire in the combustible region.

[0005] In another aspect, an apparatus for monitoring a combustible region for the occurrence of a fire in the combustible region is provided. The apparatus includes an optical signal collecting unit positioned inside the combustible region and an optical signal processing unit positioned outside the combustible region. The apparatus also includes one or more optical fiber bundles optically interconnecting the optical signal collecting unit and the optical signal processing unit. The optical interconnection enables the optical signal processing unit to receive at least one optical signal from the optical signal collecting unit and process one or more characteristics of the at least one optical signal to determine whether the at least one optical signal is indicative of a fire in the combustible region.

[0006] In yet another aspect, a method for verifying functionality of an optical-based fire detection system that monitors a combustible area for the occurrence of a fire in the combustible area is provided. The method includes emitting light in the combustible area. The method also includes collecting the emitted light. The method further includes directing the collected light to an optical signal processing unit positioned outside the combustible area to enable the optical signal processing unit to process the collected light to verify functionality of the optical-based fire detection system.

[0007] In yet another aspect, an apparatus for verifying functionality of an optical-based fire detection system monitoring a combustible region for the occurrence of a fire in the combustible region is provided. The apparatus includes an optical signal collecting unit positioned inside the combustible region. The apparatus also includes an optical signal processing unit positioned outside the combustible region. The apparatus further includes one or more optical fiber bundles optically interconnecting the optical signal collecting unit and the optical signal processing unit. The optical interconnection enables the optical signal processing unit to receive and process at least one optical signal from the optical signal collecting unit to verify functionality of the optical signal collecting unit, thereby verifying functionality of the optical-based fire detection system.

[0008] In another aspect, an optical-based fire detection system has a fire detection mode and a system calibration mode. In the fire detection mode, the system monitors a combustible area for the occurrence of a fire in the combustible area. In the system calibration mode, functionality of the system can be verified. The optical-based fire detection system includes an optical signal collection unit positioned inside the combustible area. The optical-based fire detection system also includes an optical signal processing unit positioned outside the combustible area. The optical-based fire detection system further includes an optical signal calibration unit positioned outside the combustible area. The optical-based fire detection system also includes one or more optical fiber bundles optically interconnecting the optical signal collection unit, the optical signal processing unit, and the optical signal calibration unit. The optical interconnection enables the optical signal processing unit to receive at least one optical signal from the optical signal collection unit and process one or more characteristics of the at least one optical signal to determine whether the at least one optical signal is indicative of a fire in the combustible area when the fire detection system is in the fire detection mode. The optical interconnection enables the optical signal processing unit to receive at least one calibration optical signal from the optical signal collection unit and process the at least one calibration optical signal to verify functionality of the optical signal collection unit when the fire detection system is in a system calibration mode, thereby verifying functionality of the optical-based fire detection system.

[0009] Other aspects will become apparent from the following detailed description, the accompanying drawings, and the appended claims. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic block diagram of an aircraft implementing an exemplary optical-based fire detection system having a fire detection mode and a system calibration mode, according to an exemplary implementation. [Figure 2] 2 illustrates an exemplary control unit used within the optical-based fire detection system of FIG. 1. [Figure 3]2 is a reduced representation of the schematic block diagram of FIG. 1 showing only the active components of the fire detection system in fire detection mode according to one embodiment. [Figure 4] 4 is a flow diagram illustrating an exemplary method for operating the control unit of FIG. 2 during the fire detection mode of FIG. 3. [Figure 5] 4 is a flow diagram illustrating another exemplary method for operating the control unit of FIG. 2 during the fire detection mode of FIG. 3. [Figure 6] 2 is a reduced representation of the schematic block diagram of FIG. 1 showing only the active components of the fire detection system in system calibration mode according to one embodiment. [Figure 7] 7 is a flow diagram illustrating an exemplary method for operating the control unit of FIG. 2 during the system calibration mode of FIG. 6. [Figure 8] 7 is a flow diagram illustrating another exemplary method for operating the control unit of FIG. 2 during the system calibration mode of FIG. 6. [Figure 9] FIG. 1 is a flow diagram of an aircraft production and service method. [Figure 10] FIG. 1 is a block diagram of an aircraft. DETAILED DESCRIPTION OF THE INVENTION

[0011] This application is directed to optical-based fire detection systems and methods. The particular optical-based fire detection systems and methods, and the industries in which they are implemented, may vary. It should be understood that the following disclosure provides several examples or multiple examples for implementing various features of various embodiments. To simplify the disclosure, specific examples of components and arrangements are described. These are merely examples and are not limiting.

[0012] As an example, the following disclosure describes an optical-based fire detection system and method implemented by Boeing for aircraft subject to Federal Aviation Administration (FAA) regulations. The specifications of the FAA regulations are known and therefore will not be described.

[0013] Referring to Figure 1, an aircraft 10 is shown embodying an exemplary optical-based fire detection system 100 having a fire detection mode and a system calibration mode, according to one exemplary embodiment. In Figure 1, single solid lines represent electrical connections between components, double solid lines represent fiber optic connections between components, and single dashed lines represent light emitted from a source. The fire detection system 100 may be used in any application of the aircraft 10, such as in a fuel tank (not shown) of the aircraft 10.

[0014] In one exemplary embodiment shown in FIG. 1 , aircraft 10 may be any type of vehicle. For example, without limitation, aircraft 10 may be a fixed-wing, rotary-wing, or lighter-than-air aircraft. Aircraft 10 may be manned or unmanned. As one example, aircraft 10 may be a commercial passenger aircraft operated by an airline, a cargo aircraft operated by a commercial or public entity, a military aircraft operated by the military or other government agency, a personal aircraft operated by an individual, or any other type of aircraft operated by another aircraft operator. As another example, aircraft 10 may be an unmanned aerial vehicle (UAV) operated by a remote operator. Accordingly, one skilled in the art will understand that aircraft 10 may be designed to perform any mission and may be operated by any operator.

[0015] The exemplary embodiment of Figure 1 is particularly applicable to certain locations on the aircraft 10. For example, the embodiment of Figure 1 may be applied to the engine compartment, auxiliary power unit (APU) compartment, or cargo compartment of the aircraft 10. As another example, the embodiment of Figure 1 may be applied within a fuel tank or flammable leak zone. Other applications are possible.

[0016] The optical-based fire detection system 100 includes a control unit 110 connected to an optical signal processing unit 130 via line 112 and to an optical signal calibration unit 140 via line 114. As shown in FIG. 2 , the control unit 110 includes a processor 116 that executes instructions from a fire detection system control program 117 stored in an internal data storage device 118, an external data storage device (not shown), or a combination thereof, to control the signal processing unit 130 and the calibration unit 140. The processor 116 may include any type of technology. For example, the processor 116 may include a dedicated electronic processor. Other types of processors and technologies are possible. The internal data storage device 118 may include any type of technology. For example, the internal data storage device 118 may include random access memory (RAM), read-only memory (ROM), solid-state memory, or any combination thereof. Other types of data storage devices and technologies are possible.

[0017] Control unit 110 further includes input / output (I / O) devices 120, which may include any type of technology. For example, I / O devices 120 may include a keypad, a keyboard, a touch-sensitive display screen, a liquid crystal display (LCD) screen, a microphone, a speaker, or any combination thereof. Other types of I / O devices and technologies are possible.

[0018] 1 , the fire detection system 100 includes an optical signal collection unit 150 in the form of one or more optical receivers positioned inside the combustible area 160. The one or more optical receivers 150 may include any number of the same type of receivers, any combination of different types of receivers, and may be positioned or mounted in any manner, at any location, and in any orientation inside the combustible area 160. As one example, the one or more optical receivers 150 may include a fisheye lens. Other types of optical lenses are possible.

[0019] The fire detection system 100 also includes one or more calibration light emitters 170 positioned inside the combustible area 160. The one or more light emitters 170 may include any number of light emitters of the same type, any combination of light emitters of different types, and may be positioned or mounted in any manner, at any location, and in any orientation inside the combustible area 160. As an example, the one or more light emitters 170 may include a directional light emitter, an omnidirectional light emitter, an indirect light emitter, an array of light-emitting diodes (LEDs), or a combination thereof. As another example, the one or more light emitters 170 may include a portable light source hand-carried into the combustible area 160 by a user to enable the user to manually operate the portable light source to emit light of several predetermined wavelengths and several predetermined intensities in the combustible area 160.

[0020] The fire detection system 100 further includes a fiber optic splitter 180 that optically interconnects the one or more light emitters 170 on line 172, the signal processing unit 130 on line 132, and the calibration unit 140 on line 142. The signal processing unit 130 and the one or more light receivers 150 are optically interconnected via line 152. Lines 132, 142, 152, and 172 comprise one or more fiber optic bundles that optically interconnect the signal processing unit 130, the calibration unit 140, the light receiver 150, and the light emitter 170.

[0021] The receiver 150 receives emitted light on line 174 from the light emitter 170 when the fire detection system 100 is in a system calibration mode. The receiver 150 receives emitted light on line 162 from the light source 164 (e.g., a potential fire) when the fire detection system 100 is in a fire detection mode.

[0022] Referring to Figure 3, a reduced representation of the schematic block diagram of Figure 1 is shown. More specifically, Figure 3 shows only the active components of fire detection system 100 in fire detection mode, according to one embodiment. When fire detection system 100 is in fire detection mode, signal processing unit 130 receives at least one optical signal on line 152 from receiver 150. The optical signal on line 152 is output from receiver 150 in response to light emitted on line 162 from light source 164, which may be a potential fire. Signal processing unit 130 then processes one or more characteristics of the at least one optical signal on line 152 to determine whether the at least one optical signal is indicative of a fire in combustible region 160 (i.e., whether the light emitted on line 162 from light source 164 is indicative of a fire).

[0023] 4, a flow diagram 400 is shown depicting an exemplary method for operating the control unit 110 of FIG. 2 during the fire detection mode of FIG. 3. At block 402, the fire detection system 100 is set to a normal operating mode (i.e., fire detection mode). As indicated at block 404, the signal processing unit 130 monitors light received from one or more receivers 150. Then, at block 406, the signal processing unit 130 processes the light received from the receivers 150 to provide a measurement set equal to "m." The process then proceeds to block 410.

[0024] At block 410, a determination is made as to whether the measurement m is greater than "Z1," which is a calibrated detection threshold set during a system calibration mode, as will be described later herein with respect to the flow diagram of FIG. 7. If the determination at block 410 is negative (i.e., the measurement m is not greater than the configured detection threshold Z1), the process proceeds to block 412. At block 412, normal operation of the fire detection system 100 is reported, meaning that no fire has been detected in the combustible region 160 based on the measurement m provided at block 406.

[0025] The process then proceeds to block 414 where a determination is made as to whether a shutdown signal has been received to shut down the fire detection system 100. If the determination at block 414 is negative (i.e., a signal to shut down the fire detection system 100 has not been received), the process returns to block 404 and continues monitoring for light received from the receiver 150. However, if the determination at block 414 is positive (i.e., a signal to shut down the fire detection system 100 has been received), the process ends.

[0026] However, if the determination at block 410 is positive (i.e., the measurement m is greater than the calibrated detection threshold Z1), the process proceeds to block 416. At block 416, a message is sent indicating that a fire has been detected in the flammable area 160. Optionally, at block 418, a warning device (e.g., either visual or audible) may be triggered in the cockpit of the aircraft 10 (FIG. 1), or a fire suppression system may be activated, or both. These are just examples of devices and systems that may be triggered in response to detecting a fire in the flammable area 160. Other types of devices and systems that may be triggered are possible.

[0027] The process then proceeds to block 420, where a determination is made as to whether the fire detection system 100 should continue operating in normal mode (i.e., fire detection mode). If the determination at block 420 is affirmative (i.e., continue operating in fire detection mode), the process returns to block 404 to continue monitoring light received from the receiver 150. However, if the determination at block 420 is negative (i.e., cease operation in fire detection mode), the process ends.

[0028] Referring to Figure 5, a flow diagram 500 is shown depicting another exemplary method for operating the control unit 110 of Figure 2 during the fire detection mode of Figure 3. In block 510, a combustible region is monitored for the occurrence of a fire in the combustible region. In block 520, light emitted from the combustible region is collected, as illustrated in block 520. The collected light is then directed to an optical signal processing unit positioned outside the combustible region in block 530. In block 540, the collected light is processed in the optical signal processing unit positioned outside the combustible region to determine whether the collected light is indicative of a fire in the combustible region. The process then ends.

[0029] In some embodiments, the wavelength and intensity of the collected light are processed to determine whether the collected light is indicative of a fire in a combustible area.

[0030] In some embodiments, emitted light that is only inside the combustible region is collected.

[0031] In some embodiments, the collected light is directed to an optical signal processing unit via one or more fiber optic bundles.

[0032] Referring to FIG. 6, a reduced-scale representation of the schematic block diagram of FIG. 1 is shown. More specifically, FIG. 6 shows only the active components of the fire detection system 100 in a system calibration mode according to one embodiment. When the fire detection system 100 is in the system calibration mode, the control unit 110 controls the calibration unit 140 to emit at least one calibration optical signal on line 142 to the fiber splitter 180. The emitted optical signal has several predetermined wavelengths and several predetermined intensities. The fiber splitter splits the emitted light between the signal processing unit 130 and the optical receiver 150. As an example, the emitted light may be split so that 95% goes to the light emitter 170 on line 172 and 5% goes to the signal processing unit 130 on line 132. Other splitting ratios are possible, such as 90%-10% or 99%-1%.

[0033] In response to receiving light on line 172 from fiber splitter 180, light emitter 170 provides emitted light on line 174. Light receiver 150 then provides at least one optical signal on line 152 to signal processing unit 130 in response to the light on line 174. Signal processing unit 130 then processes the at least one optical signal on line 152 to verify the functionality of light receiver 150, and thereby verify the functionality of fire detection system 100.

[0034] Referring to FIG. 7, a flow diagram 700 is shown depicting an exemplary method for operating the control unit 110 of FIG. 2 during the system calibration mode of FIG. 6. At block 702, the fire detection system 100 is set to a calibration mode (i.e., system calibration mode). As depicted at block 704, a signal indicating that the calibration unit 140 is emitting light is received. Then, at block 706, the signal processing unit 130 monitors light received on line 132 from the fiber splitter 180. As depicted at block 708, the signal processing unit 130 processes the light received from the fiber splitter 180 to provide a measurement set equal to “X1.” The process then proceeds to block 710, where a laser degradation value “β” is calculated from X1. As an example, the value of β may be set equal to X1 / X0, where “X0” is a value set at the factory during manufacture.

[0035] Then, in block 712, β is set to "β min " is larger than "β max A determination is made as to whether β is less than β min and β max are both factory set values ​​during manufacturing. min The value of and β maxIf the value of β is not between β and β, the process proceeds to block 714. At block 714, an error message is sent indicating that the level (i.e., one or more values ​​of β) is out of specification, meaning that one or more values ​​of β are too high or too low. Then, at block 716, a message is sent indicating that the attempt to calibrate the fire detection system 100 failed. The process then ends.

[0036] However, if the determination at block 712 is positive (i.e., the value of β is min The value of and β max If the value of Y is between β and γ, the process proceeds to block 720, where the signal processing unit 130 monitors the light received on line 152 from the receiver 150. Then, as shown in block 722, the signal processing unit 130 processes the received light to provide a measurement value "Y1." The process then proceeds to block 724, where a deployed receiver degradation value "α" is calculated from Y1 and β. As one example, the value of α may be set equal to Y1 / βY0, where "Y0" is a value set at the factory during manufacturing.

[0037] Then, in block 730, α is set to "α min " is larger than "α max A determination is made as to whether α is less than α min and α max are both factory set values ​​during manufacturing. min The value of α max If the value of α is not between α and α (i.e., not between α and α), the process proceeds to block 714. In block 714, an error message is sent indicating that the level (i.e., one or more values ​​of α) is out of specification, meaning that one or more values ​​of α are too high or too low. Then, in block 716, a message is sent indicating that the attempt to calibrate the fire detection system 100 failed.

[0038] However, if the determination at block 730 is positive (i.e., the value of α is min The value of αmax If the value of γ is between α and γ (between α and γ), the process proceeds to block 732. In block 732, a fire detection threshold "Z1" is calculated from α. As an example, the value of Z1 may be set to αγY0, where "γ" and "Y0" are values ​​set at the factory during manufacturing. The value of γ is between 0 and 1 and represents a reduced light reception rate (e.g., the lens of the receiver 150 is coated with something to make it less light-transmitting). Then, in block 734, a message is sent indicating that the attempt to calibrate the fire detection system 100 was successful. The process then ends.

[0039] It will be apparent that measurements X0 and Y0 are baseline values ​​before any degradation occurs (i.e., α = β = 1 indicates no degradation). More specifically, X0 and Y0 are direct measurements from calibration unit 140 (X0) and optical receiver 150 (Y0). Z0 is the baseline detection threshold and is calculated using Y0 and γ (e.g., Z0 = γY0). If linear scaling of power levels is used (i.e., α, β, and Z0 are linear functions), γ has a value between 0 and 1. However, it is conceivable that α, β, and Z0 may include complex functions that may be nonlinear. In this case, the γ value is between 0 and 1, but may not be linear with respect to power level.

[0040] It will also be apparent that measurement X1 is a degraded laser power emission value, and measurement Y1 is a degraded optical power reception value. As a result, the total available power (whether emitted or received) is reduced. The degree of degradation is tracked and calculated using a laser degradation factor β and a deployed receiver degradation factor α. In one example, β is calculated using X0 and X1 (e.g., β = X1 / X0), and α is calculated using β, Y1, and Y0 (e.g., α = Y1 / βY0). These are merely examples of how the degradation factors α and β can be calculated; other methods of calculating α and β are also possible.

[0041] Furthermore, it should be apparent that Z1 is a new detection threshold that replaces the baseline detection threshold Z0 to compensate for degraded laser output from the calibration unit 140 and degraded light reception by the optical receiver 150. In one example, Z1 is calculated using degradation coefficients α and β, γ, and Y0 (e.g., Z1 = αγY0). These are only examples of how to calculate Z1, and other methods of calculating Z1 are also possible. Z1 may include not only a linear function but also a complex function.

[0042] 8, a flow diagram 800 is shown depicting another exemplary method for operating the control unit 110 of FIG. 2 during the system calibration mode of FIG. 6. At block 810, light is emitted in the combustible area. At block 820, the emitted light is collected. At block 830, the collected light is then directed to an optical signal processing unit positioned outside the combustible area to enable the optical signal processing unit to process the collected light to verify functionality of the optical-based fire detection system.

[0043] In some embodiments, light having a number of predetermined wavelengths and a number of predetermined intensities is emitted from a light source mounted inside the combustible area.

[0044] In some embodiments, light having several predetermined wavelengths and several predetermined intensities is emitted from a portable light source that is hand-carried by a user into the flammable area.

[0045] In some embodiments, light emitted only inside the combustible region is collected.

[0046] In some embodiments, the collected light is directed to an optical signal processing unit via one or more fiber optic bundles.

[0047] In some embodiments, the collected light is directed to an optical signal processing unit via one or more fiber optic splitters.

[0048] In some embodiments, light emitted from an optical signal calibration unit positioned outside the flammable area is directed through at least one fiber optic splitter.

[0049] In some embodiments, a laser depletion factor is calculated that indicates a reduction in emitted light in the flammable region, and the light emitted from the optical signal calibration unit is adjusted based on the laser depletion factor to compensate for the reduction in emitted light in the flammable region.

[0050] In some embodiments, a deployed receiver degradation factor is calculated that indicates a reduction in collected light in the combustible region, and the light emitted from the optical signal calibration unit is adjusted based on the deployed receiver degradation factor to compensate for the reduction in collected light in the combustible region.

[0051] The above disclosed fire detection system 100 has a fire detection mode and a system calibration mode. In the fire detection mode, the system 100 monitors the combustible area 160 for the occurrence of a fire in the combustible area 160. In the system calibration mode, the functionality of the system 100 may be verified. It is noteworthy that the electronics of the control unit 110, the signal processing unit 130, and the calibration unit 140 of the fire detection system 100 are located separately outside the combustible area 160.

[0052] Locating the electronics outside of the flammable area 160 provides several advantages. One advantage is that the electronics are not in contact with the flammable area 160. This can avoid or reduce the number of false positives that indicate no fire when in fact there is a fire. Another advantage is that the functionality of the fire detection system 100 can be verified in situ without removing any components from the flammable area 160 of the aircraft 10.

[0053] Yet another advantage is that it eliminates the need to route metal wires in a flammable environment, which can experience induced currents and voltages due to electromagnetic coupling from nearby currents that generate electromagnetic fields, or direct electromagnetic coupling from electromagnetic fields impinging on the aircraft 10.

[0054] Also notably, the processor 116 of the control unit 110 executes instructions of the fire detection system control program 117 stored in the data storage device 118 to compensate for degradation of the laser output from the calibration unit 140 and degradation of the optical characteristics of the receiver 150. Degradation of the laser output may occur if the calibration unit 140 deviates from its calibrated range over time. Degradation of the optical characteristics may occur if the optics of the receiver 150 become obscured or dirty (e.g., by dust, etc.). Compensation is provided by calculating a new fire detection threshold (i.e., Z1) that replaces the baseline detection threshold value Z0. Thus, the detection threshold of the fire detection system 100 is adjusted based on the degree of degradation of the laser output from the calibration unit 140 and the degree of degradation of the optical characteristics of the receiver 150.

[0055] Each of the fire detection mode and the system calibration mode may be implemented using coded instructions (e.g., non-transitory computer- and / or machine-readable instructions), including a fire detection system control program 117 executed by the processor 116 of the control unit 110, such as shown in the exemplary fire detection system 100 described above in connection with FIGS. 1 and 2. The program 117 may be embodied in software stored on a tangible computer-readable storage medium, such as a CD-ROM, floppy disk, hard drive, digital versatile disk (DVD), Blu-ray disk, or memory associated with the processor 116, although alternatively, the program may be executed in whole or in part by a device other than the processor 116 and / or may be embedded in firmware or dedicated hardware. As used herein, the term tangible computer-readable storage medium is expressly defined to include any type of computer-readable storage device and / or storage disk, to exclude propagated signals, and to exclude transmission media. As used herein, "tangible computer-readable storage medium" and "tangible machine-readable storage medium" are used interchangeably.

[0056] Many other ways of implementing the exemplary fire detection system 100 may alternatively be used. The order of execution of the blocks may be changed, and / or some of the blocks described with reference to the exemplary flow diagrams may be modified, eliminated, or combined. Furthermore, as used herein, the term "at least" is open-ended in the same way that the term "comprises" is open-ended when used as a transitional term in the preamble of a claim.

[0057] An example manner of implementing the example aircraft-based fire detection system 100 is illustrated in Figure 1, although one or more of the elements, processes, and / or devices illustrated in Figure 1 may be combined, divided, rearranged, omitted, eliminated, and / or implemented in any other manner. Furthermore, the example control unit 110 and / or more generally the example aircraft-based fire detection system 100 of Figure 1 may be implemented by hardware, software, firmware, and / or any combination of hardware, software, and firmware. Thus, for example, the example control unit 110 and / or more generally the example aircraft-based fire detection system 100 may be implemented by one or more analog or digital circuits, logic circuits, programmable processors, application specific integrated circuits (ASICs), programmable logic devices (PLDs), and / or field programmable logic devices (FPLDs).

[0058] Embodiments of the present disclosure may be described in the context of an aircraft manufacturing and service method 1000 shown in Figure 9 and an aircraft 1002 shown in Figure 10. During pre-production, the aircraft manufacturing and service method 1000 may include specification and design 1004 of the aircraft 1002 and material procurement 1006. During production, component / subassembly manufacturing 1008 and system integration 1010 of the aircraft 1002 occurs. The aircraft 1002 may then undergo certification and delivery 1012 and be placed into service 1014. While in customer operation, the aircraft 1002 is scheduled for routine maintenance and service 1016, which may include modification, reconfiguration, refurbishment, etc.

[0059] Each process of method 1000 may be performed or carried out by a system integrator, a third party, and / or an operator (e.g., a customer). For purposes of this specification, a system integrator may include, but is not limited to, any number of aircraft manufacturers and major system subcontractors, a third party may include, but is not limited to, any number of vendors, subcontractors, and suppliers, and an operator may be an airline, a leasing company, a military organization, a service organization, etc.

[0060] 10 , an aircraft 1002 produced by example method 1000 may include an airframe 1018 having a number of systems 1020 and an interior 1022. Examples of the number of systems 1020 may include one or more of a propulsion system 1024, an electrical system 1026, a hydraulic system 1028, and an environmental system 1030. Any number of other systems may be included.

[0061] The disclosed fire detection systems and methods may be employed at any one or more stages of aircraft manufacturing and service method 1000. As one example, components or subassemblies corresponding to component / subassembly manufacturing 1008, system integration 1010, and / or maintenance and service 1016 may be assembled using the disclosed fire detection systems and methods. As another example, an airframe 1018 may be constructed using the disclosed fire detection systems and methods. Also, one or more apparatus embodiments, method embodiments, or a combination thereof may be utilized in component / subassembly manufacturing 1008 and / or system integration 1010, for example, by significantly streamlining or reducing the cost of assembly of the aircraft 1002 (e.g., the airframe 1018 and / or the interior 1022). Similarly, one or more of the system embodiments, method embodiments, or a combination thereof may be utilized during the operational life of the aircraft 1002, for example, but not limited to, maintenance and service 1016.

[0062] The disclosed fire detection systems and methods are described in the context of aircraft in the aviation industry in accordance with military and space regulations. It is contemplated that the disclosed fire detection systems and methods may be implemented in any industry in accordance with applicable industry standards. The particular fire detection system and method may be selected and tailored to the particular application.

[0063] The present disclosure further includes embodiments according to the following clauses:

[0064] Article 1. 1. A method 500 of operating an optical-based fire detection system 100, comprising: monitoring 510 the flammable area 160 for the occurrence of a fire in said flammable area; collecting 520 light emitted from the combustible region; directing 530 the collected light to an optical signal processing unit 130 positioned outside the combustible region; and The method 500 includes processing 540 the collected light in the optical signal processing unit positioned outside the combustible region to determine whether the collected light is indicative of a fire in the combustible region.

[0065] Article 2. The method 500 of clause 1, wherein processing the collected light in the optical signal processing unit includes processing the wavelength and intensity of the collected light to determine whether the collected light indicates a fire in the combustible area.

[0066] Article 3. 3. The method of claim 1 or 2, wherein collecting light emitted from the combustible region includes collecting emitted light only inside the combustible region.

[0067] Article 4. 4. The method 500 of any one of clauses 1 to 3, wherein directing the collected light to the optical signal processing unit comprises directing the collected light to the optical signal processing unit via one or more optical fiber bundles.

[0068] Article 5. 1. An apparatus for monitoring a flammable area (160) for the occurrence of a fire in said flammable area, comprising: an optical signal collection unit 150 positioned inside the flammable area; an optical signal processing unit 130 positioned outside the flammable area; and and one or more optical fiber bundles 152 optically interconnecting the optical signal collecting unit and the optical signal processing unit to enable the optical signal processing unit to receive at least one optical signal from the optical signal collecting unit and process one or more characteristics of the at least one optical signal to determine whether the at least one optical signal is indicative of a fire in the combustible region.

[0069] Article 6. 6. The apparatus described in clause 5, wherein the optical signal collection unit includes at least one optical receiver positioned inside the combustible region.

[0070] Article 7. 7. The apparatus of clause 6, wherein the at least one optical receiver includes a fisheye lens.

[0071] Article 8. 1. A method 800 for verifying functionality of an optical-based fire detection system monitoring a combustible area for the occurrence of a fire in the area, comprising: emitting light in the combustible area 810; collecting 820 the emitted light, and The method 800 includes directing 830 the collected light to an optical signal processing unit positioned outside the combustible area to enable the optical signal processing unit to process the collected light to verify functionality of the optical-based fire detection system.

[0072] Article 9. 8. The method of claim 8, wherein emitting light in the combustible area includes emitting light having a number of predetermined wavelengths and a number of predetermined intensities from a light source mounted inside the combustible area.

[0073] Article 10. The method 800 of clause 8, wherein emitting light in the combustible area includes emitting light having several predetermined wavelengths and several predetermined intensities from a portable light source carried by a user into the combustible area.

[0074] Article 11. 11. The method 800 of any one of clauses 8 to 10, wherein collecting the emitted light includes collecting emitted light only inside the combustible region.

[0075] Article 12. 12. The method 800 of any one of clauses 8 to 11, wherein directing the collected light to the optical signal processing unit comprises directing the collected light to the optical signal processing unit via one or more optical fiber bundles.

[0076] Article 13. 13. The method 800 of any one of clauses 8 to 12, wherein directing the collected light to the optical signal processing unit via one or more optical fiber bundles comprises directing the collected light to the optical signal processing unit via at least one optical fiber splitter.

[0077] Article 14. 14. The method 800 of clause 13, further comprising directing light emitted from an optical signal calibration unit positioned outside the flammable area through the at least one fiber splitter.

[0078] Article 15. calculating 710 a laser degradation factor indicative of the reduction in emitted light in the flammable region; and 15. The method 800 of clause 14, further comprising adjusting the emitted light emitted from the optical signal calibration unit based on the laser degradation factor to compensate for the reduction in the emitted light in the combustible region.

[0079] Article 16. calculating a deployed receiver degradation factor indicative of the reduction in collected light in the combustible region; and 15. The method 800 of clause 14, further comprising adjusting the emitted light from the optical signal calibration unit based on the deployed receiver degradation factor to compensate for the reduction in the collected light in the combustible region.

[0080] Article 17. 1. An apparatus for verifying functionality of an optical-based fire detection system (100) that monitors a combustible area (160) for the occurrence of a fire in said combustible area, comprising: an optical signal collection unit 150 positioned inside the flammable area; an optical signal processing unit 130 positioned outside the flammable area; and an apparatus comprising one or more optical fiber bundles optically interconnecting the optical signal collection unit and the optical signal processing unit to enable the optical signal processing unit to receive at least one optical signal from the optical signal collection unit and process the at least one optical signal to verify functionality of the optical signal collection unit, thereby verifying functionality of the optical-based fire detection system.

[0081] Article 18. 18. The apparatus of clause 17, wherein the optical signal collecting unit includes at least one light emitter positioned inside the combustible region.

[0082] Article 19. 19. The apparatus of clause 18, wherein the at least one light emitter positioned inside the combustible area includes a combination of directional light emitters, indirect light emitters, and non-directional light emitters positioned inside the combustible area.

[0083] Article 20. 19. The apparatus of clause 18, wherein the at least one light emitter positioned inside the combustible area includes an array of light emitting diodes positioned inside the combustible area.

[0084] Article 21. The apparatus described in clause 18, wherein the at least one light emitter positioned inside the combustible area includes a portable light source carried by hand into the combustible area by a user to enable the user to manually operate the portable light source to emit light of several predetermined wavelengths and several predetermined intensities in the combustible area.

[0085] Article 22. 22. The apparatus of any one of clauses 17 to 21, wherein the optical signal collection unit includes at least one optical receiver positioned inside the combustible area.

[0086] Article 23. 23. The apparatus of claim 22, wherein the at least one optical receiver includes a fisheye lens.

[0087] Article 24. 24. The apparatus of any one of clauses 17 to 23, wherein (i) the at least one optical signal from the optical signal collecting unit comprises light having several predetermined wavelengths and several predetermined intensities, and (ii) the optical signal processing unit processes the predetermined wavelengths and the predetermined intensities to verify the functionality of the optical signal collecting unit, thereby verifying the functionality of the optical-based fire detection system.

[0088] Article 25. 25. The apparatus of any one of clauses 17 to 24, further comprising an optical signal calibration unit positioned outside the flammable area.

[0089] Article 26. 26. The apparatus of clause 25, wherein the optical signal calibration unit emits light that is adjusted based on at least one of a calculated laser degradation factor and a calculated deployed optical receiver degradation factor.

[0090] Article 27. 26. The apparatus of clause 25, further comprising an optical fiber splitter disposed within the one or more optical fiber bundles for optically interconnecting the optical signal collection unit, the optical signal processing unit, and the optical signal calibration unit.

[0091] Article 28. 1. An optical-based fire detection system (100) having a fire detection mode and a system calibration mode, wherein in the fire detection mode the system monitors a combustible area (160) for the occurrence of a fire therein, and in the system calibration mode functionality of the system may be verified, an optical signal collection unit 150 positioned inside the flammable area; an optical signal processing unit 130 positioned outside the flammable area; an optical signal calibration unit 140 positioned outside the flammable area; and The system 100 comprises one or more optical fiber bundles 132, 142, 152 optically interconnecting the optical signal collection unit, the optical signal processing unit, and the optical signal calibration unit to (i) enable the optical signal processing unit to receive at least one optical signal from the optical signal collection unit and process one or more characteristics of the at least one optical signal to determine whether the at least one optical signal indicates a fire in the combustible area when the fire detection system is in the fire detection mode, and (ii) enable the optical signal processing unit to receive at least one calibration optical signal from the optical signal calibration unit and process the at least one calibration optical signal to verify functionality of the optical signal collection unit, thereby verifying functionality of the optical-based fire detection system, when the fire detection system is in the system calibration mode.

[0092] Article 29. The system 100 described in clause 28 further comprises an optical fiber splitter disposed within the one or more optical fiber bundles for optically interconnecting the optical signal collection unit, the optical signal processing unit, and the optical signal calibration unit.

[0093] Article 30. 29. The system 100 of clause 28, wherein the optical signal calibration unit emits light that is adjusted based on at least one of a calculated laser degradation factor and a calculated deployed optical receiver degradation factor.

[0094] Moreover, while various disclosed embodiments have been shown and described, modifications will occur to those skilled in the art upon reading this specification, and the present application includes such modifications and is limited only by the scope of the claims.

Claims

1. A method (500) for operating an optical-based fire detection system (100), To monitor the flammable area (510) for the occurrence of a fire in the flammable area (160), Collecting light emitted from the aforementioned flammable area (520), The collected light is guided to an optical signal processing unit (130) located outside the flammable area (530), and A method (500) comprising processing the collected light in an optical signal processing unit located outside the flammable area (540) in order to determine whether the collected light indicates a fire in the flammable area.

2. The method according to claim 1 (500), wherein processing the collected light in the optical signal processing unit includes processing the wavelength and intensity of the collected light to determine whether the collected light indicates a fire in the flammable area.

3. The method according to claim 1 or 2 (500), wherein collecting light emitted from the flammable region includes collecting light emitted only from inside the flammable region.

4. The method according to claim 1 (500), wherein guiding the collected light to the optical signal processing unit includes guiding the collected light to the optical signal processing unit via one or more optical fiber bundles.

5. A device for monitoring a flammable area (160) for the occurrence of a fire in the flammable area, An optical signal acquisition unit (150) located inside the flammable area, An optical signal processing unit (130) located outside the flammable region, and An apparatus comprising one or more optical fiber bundles (152) that optically interconnect the optical signal acquisition unit and the optical signal processing unit, enabling the optical signal processing unit to receive at least one optical signal from the optical signal acquisition unit and process one or more characteristics of the at least one optical signal in order to determine whether the at least one optical signal indicates a fire in the flammable area.

6. The apparatus according to claim 5, wherein the optical signal acquisition unit includes at least one photodetector located inside the flammable area.

7. The apparatus according to claim 6, wherein the at least one light receiver includes a fisheye lens.

8. A method (800) for verifying the functionality of an optical-based fire detection system that monitors a flammable area for the occurrence of a fire in the flammable area, Emitting light in the aforementioned flammable region (810), Collecting the emitted light (820), and A method (800) to verify the functionality of the optical-based fire detection system, including guiding the collected light to an optical signal processing unit (830) located outside the flammable area so that the collected light can be processed by the optical signal processing unit.

9. The method according to claim 8 (800), wherein emitting light in the flammable region includes emitting light having several predetermined wavelengths and several predetermined intensities from a light source installed inside the flammable region.

10. The method according to claim 8 (800), wherein emitting light in the flammable area includes emitting light having several predetermined wavelengths and several predetermined intensities from a portable light source carried by hand into the flammable area by the user.

11. The method according to any one of claims 8 to 10 (800), wherein collecting the emitted light includes collecting the emitted light that is located only inside the flammable area.

12. The method according to claim 8 (800), wherein guiding the collected light to the optical signal processing unit includes guiding the collected light to the optical signal processing unit via one or more optical fiber bundles.

13. The method according to claim 8 (800), wherein guiding the collected light to the optical signal processing unit via one or more optical fiber bundles includes guiding the collected light to the optical signal processing unit via at least one optical fiber splitter.

14. The method according to claim 13 (800), further comprising guiding light emitted from an optical signal calibration unit located outside the flammable region through the at least one optical fiber splitter.

15. Calculate the laser degradation coefficient that indicates the reduction of light emitted in the flammable region (710), and The method according to claim 14 (800), further comprising adjusting the emitted light from the optical signal calibration unit based on the laser degradation coefficient in order to compensate for the reduction of the emitted light in the flammable region.

16. To calculate the degradation coefficient of the deployed photodetector that shows the reduction of collected light in the aforementioned flammable region, and The method according to claim 14 (800), further comprising adjusting the light emitted from the optical signal calibration unit based on the deployed photodetector degradation coefficient in order to compensate for the reduction of the collected light in the flammable region.

17. An apparatus for verifying the functionality of an optical-based fire detection system (100) that monitors a flammable area (160) for the occurrence of a fire in the flammable area, An optical signal acquisition unit (150) located inside the flammable area, An optical signal processing unit (130) located outside the flammable region, and An apparatus comprising one or more optical fiber bundles that optically interconnect the optical signal acquisition unit and the optical signal processing unit, in order to verify the functionality of the optical signal acquisition unit and thereby verify the functionality of the optical-based fire detection system, such that the optical signal processing unit receives at least one optical signal from the optical signal acquisition unit and processes the at least one optical signal.

18. The apparatus according to claim 17, wherein the optical signal acquisition unit includes at least one light emitter located inside the flammable area.

19. The apparatus according to claim 18, wherein the at least one light emitter located inside the flammable region includes a combination of a directional light emitter, an indirect light emitter, and an omnidirectional light emitter located inside the flammable region.

20. The apparatus according to claim 18, wherein the at least one light-emitting device located inside the flammable region includes an array of light-emitting diodes located inside the flammable region.

21. The apparatus according to claim 18, wherein the at least one light emitter located inside the flammable area includes a portable light source that is carried by hand into the flammable area by the user, enabling the user to manually operate the portable light source to emit light of several predetermined wavelengths and several predetermined intensities in the flammable area.

22. The apparatus according to any one of claims 17 to 21, wherein the optical signal acquisition unit includes at least one photodetector located inside the flammable area.

23. The apparatus according to claim 22, wherein the at least one light receiver includes a fisheye lens.

24. (i) The at least one optical signal from the optical signal acquisition unit comprises light having a certain predetermined wavelength and a certain predetermined intensity, and (ii) The optical signal processing unit processes the predetermined wavelength and the predetermined intensity to verify the functionality of the optical signal acquisition unit and thereby verify the functionality of the optical-based fire detection system, according to claim 17.

25. The apparatus according to claim 17, further comprising an optical signal calibration unit positioned outside the flammable region.

26. The apparatus according to claim 25, wherein the optical signal calibration unit emits light that is adjusted based on at least one of a calculated laser degradation coefficient and a calculated deployed photodetector degradation coefficient.

27. The apparatus according to claim 25, further comprising an optical fiber splitter disposed within one or more optical fiber bundles for optically interconnecting the optical signal acquisition unit, the optical signal processing unit, and the optical signal calibration unit.

28. An optical-based fire detection system (100) having a fire detection mode and a system calibration mode, wherein in the fire detection mode, the system monitors the flammable region (160) for the occurrence of a fire in the flammable region, and in the system calibration mode, the functionality of the system can be verified, An optical signal acquisition unit (150) located inside the flammable area, An optical signal processing unit (130) located outside the aforementioned flammable region, An optical signal calibration unit (140) located outside the flammable region, and A system (100) comprising one or more optical fiber bundles (132), (142), (152) that optically interconnect the optical signal acquisition unit, the optical signal processing unit, and the optical signal calibration unit, so as to enable the optical signal processing unit to receive at least one optical signal from the optical signal acquisition unit and process the at least one calibration optical signal to determine whether the at least one optical signal indicates a fire in the flammable area when the fire detection system is in the system calibration mode.

29. The system (100) according to claim 28, further comprising an optical fiber splitter disposed in one or more optical fiber bundles for optically interconnecting the optical signal acquisition unit, the optical signal processing unit, and the optical signal calibration unit.

30. The system (100) according to claim 28 or 29, wherein the optical signal calibration unit emits light that is calibrated based on at least one of a calculated laser degradation coefficient and a calculated deployed photodetector degradation coefficient.

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