An integrated avionics system architecture based on a passive optical network

Abstract

The application provides a passive optical network-based integrated avionics system architecture, which is used for access of an optical network terminal unit group, each general processing module is connected with the optical network terminal unit group through a first optical line terminal and a first optical splitter to form a first network, each general processing module is connected with the optical network terminal unit group through a second optical line terminal and a second optical splitter to form a second network, and the first network and the second network form a first double-plane network group. The technical scheme does not need a switching chip, and avoids delay and jitter introduced by switching. Considering the fault risk of single-path communication, a double-plane network group is constructed, two independent communication paths are provided, and path-level redundancy is realized.

Description

Technical Field

[0001] This application relates to the technical field of airborne avionics systems, and more particularly to an integrated avionics system architecture based on passive optical networks. Background Technology

[0002] The architecture of civil airborne avionics systems has evolved from simple to complex, and from decentralized to highly integrated. In the early days, each avionics subsystem used dedicated equipment and networks, resulting in minimal information exchange between subsystems, high equipment redundancy, and high upgrade and maintenance costs.

[0003] In the 1970s and 80s, with the development of digital technology, federated architectures emerged. Standardized digital data buses (such as the MIL-STD-1553B bus and ARINC 429 bus) began to be used for information exchange between subsystems, improving integration and resource sharing capabilities. These buses were simple, reliable, and highly deterministic, but their data bandwidth was limited to a maximum of 2 Mbps, which became a significant limitation as aircraft functions increased.

[0004] Since the 1990s, Integrated Modular Avionics (IMA) has emerged. Through an open system architecture and high-speed networks, it integrates functions previously scattered across different hardware components into a shared, general-purpose processing module. The bus uses standard avionics full-duplex switched Ethernet (AFDX) to implement the ARINC664 protocol, achieving a maximum bus speed of 100Mbps. It also supports deterministic algorithms and dual redundancy to ensure extremely high security. However, IMA systems based on ARINC664 networks also have their limitations. On one hand, as dedicated aviation networks, there are relatively few suppliers, resulting in high costs and maintenance expenses. On the other hand, the lack of a network-wide synchronized clock and the use of a bandwidth allocation gap (BAG) mechanism for traffic shaping introduce inherent jitter, limiting determinism.

[0005] Therefore, there is an urgent need to provide an integrated avionics system network architecture that combines high security, high performance, and low cost to meet the needs of modern civil aviation electronic systems. Utility Model Content

[0006] To overcome the above shortcomings, this application provides an integrated avionics system architecture based on passive optical networks.

[0007] The objective of this application is achieved through the following technical solution:

[0008] In a first aspect, this application provides an integrated avionics system architecture based on a passive optical network (PON), the integrated avionics system architecture being used for the access of optical network terminal unit groups, the integrated avionics system architecture comprising:

[0009] The first optical splitter, the second optical splitter, and multiple general-purpose processing modules, the first optical line terminal and the second optical line terminal are installed in the first cabinet;

[0010] Each of the general-purpose processing modules is connected to the optical network terminal unit group via the first optical line terminal and the first optical splitter to form a first network; each of the general-purpose processing modules is connected to the optical network terminal unit group via the second optical line terminal and the second optical splitter to form a second network; the first network and the second network form a first dual-plane network group; each network in the first dual-plane network group is configured to perform bidirectional communication using a time-division multiple access protocol during the information transmission phase, and the communication data is transmitted after being converged by the first optical line terminal and the second optical line terminal within a fixed time slot.

[0011] Preferably, it also includes a second dual-plane network group; the second dual-plane network group includes multiple general-purpose processing modules, a third optical line terminal and a fourth optical line terminal disposed in the second cabinet, as well as a third optical splitter disposed between the optical network terminal unit group and the third optical line terminal, and a fourth optical splitter disposed between the optical network terminal unit group and the fourth optical line terminal; the second dual-plane network group and the first dual-plane network group are mutually redundant backups.

[0012] Preferably, it further includes an end system device, which is connected to the second dual-plane network group and the first dual-plane network group. The end system device is used to realize data redundancy and de-redundancy between the second dual-plane network group and the first dual-plane network group.

[0013] Preferably, the first optical line terminal, the second optical line terminal, the third optical line terminal, and the fourth optical line terminal all include a photoelectric conversion module and an optical line terminal field-programmable logic device.

[0014] Preferably, the optical network terminal unit group includes multiple remote data interface units and multiple network interface cards.

[0015] Preferably, the first, second, third, and fourth optical splitters are all passive optical splitters with a splitting ratio of 1:32. The number of general-purpose processing modules installed in the first cabinet is 6, and the number of general-purpose processing modules installed in the second cabinet is 6. The accessed optical network terminal unit group includes 16 remote data interface units and 16 network interface cards.

[0016] Preferably, the integrated avionics system architecture is used for electric vertical takeoff and landing aircraft. The first, second, third, and fourth beam splitters are all passive beam splitters with a splitting ratio of 1:16. The number of general-purpose processing modules installed in the first cabinet is 2, and the number of general-purpose processing modules installed in the second cabinet is 2. The connected optical network terminal unit group includes 8 remote data interface units and 8 network interface cards.

[0017] Preferably, the first cabinet and the second cabinet are also equipped with power modules to supply power to the processing module group and optical line terminal module in their respective cabinets.

[0018] Preferably, the power module includes a main power supply and a backup power supply, which are used to provide power for both main and backup applications.

[0019] Preferably, the integrated avionics system architecture further includes a third optical splitter and a third optical line terminal, and the first dual-plane network group further includes a third network formed by connecting each of the general processing modules through the third optical line terminal, the third optical splitter and the optical network terminal unit group.

[0020] Secondly, this application also provides a communication method for the integrated avionics system architecture described in any one of the first aspects, the method comprising:

[0021] During the information transmission phase, the first optical line terminal and the second optical line terminal use a time division multiple access protocol to allocate fixed time slots to each network terminal, and then distribute the data to the target terminal after aggregation.

[0022] Preferably, the method by which the data is aggregated by the first optical line terminal and the second optical line terminal and then distributed to the target terminal includes:

[0023] The remote data interface unit that acquires sensing information in the optical network terminal unit group is selected as the interface unit; the first optical line terminal receives the sensing information sent by the selected interface unit through the first optical splitter and sends it to the general processing module in the first cabinet; the second optical line terminal receives the sensing information sent by the selected interface unit through the second optical splitter and sends it to the general processing module in the first cabinet; the general processing module compares the consistency of the received sensing information, and if there is a discrepancy, it is discarded and an alarm message is generated.

[0024] The general processing module for sending command data is selected as the general processing module. The first optical line terminal receives the command data sent by the selected general processing module and sends it to each remote data interface unit in the optical network terminal unit group through the first optical splitter. The second optical line terminal receives the command data sent by the selected general processing module and sends it to each remote data interface unit in the optical network terminal unit group through the second optical splitter. The remote data interface units in the optical network terminal unit group compare the consistency of the received command data. If there is a discrepancy, the data is discarded and an alarm message is generated.

[0025] Preferably, the method further includes: using an optical line terminal device to send clock information to all network terminals within the network to achieve network-wide clock synchronization.

[0026] Thirdly, this application also provides a computer-readable storage medium having a computer program stored thereon, which, when executed by at least one processor, implements the steps of the method described in any of the preceding claims.

[0027] Fourthly, this application also provides a computer program product comprising a computer program that, when executed by at least one processor, implements the steps of the method described in any one of the claims.

[0028] Based on the above technical solutions and the technical problems solved, this application provides an integrated avionics system architecture based on passive optical networks (PONs). Its core lies in replacing the traditional Ethernet switching structure with a PON, achieving high security, high determinism, and low latency avionics data communication through a dual-plane redundancy design and a time-division multiple access (TDMA) mechanism. In the integrated avionics system architecture, the first and second optical splitters are passive optical devices used to distribute optical signals to multiple terminals or reverse convergence. The first cabinet houses multiple general-purpose processing modules, serving as the core data processing unit; it also includes a first optical line terminal (OLT) and a second OLT, each connecting to two independent networks. The two networks constitute a first dual-plane network group, with independent physical paths and no mutual interference. The communication mechanism involves each network using a TDMA protocol during communication; all communication data is transmitted within fixed time slots; data is converged and distributed through the OLT to achieve bidirectional communication; and the use of fixed time slot scheduling avoids data conflicts, ensuring determinism and real-time performance of communication.

[0029] Compared to related technologies where avionics networks rely on switching chips, resulting in latency and jitter, the technical solution provided in this application employs a passive optical splitter and OLT structure, eliminating the need for switching chips and avoiding the latency and jitter introduced by switching. Considering the risk of failure in single-path communication, a dual-plane network group is constructed, providing two independent communication paths to achieve path-level redundancy. Attached Figure Description

[0030] The present application will be further described below with reference to the accompanying drawings and embodiments.

[0031] Figure 1 This is a schematic diagram of an integrated avionics system architecture based on a passive optical network provided in an embodiment of this application.

[0032] Figure 2 This is a schematic diagram illustrating the communication transmission of sensor data from a remote data interface unit to a general processing module, provided in an embodiment of this application.

[0033] Figure 3 This is a schematic diagram illustrating the communication transmission of actuator data from a general processing module to a remote data interface unit, provided in an embodiment of this application.

[0034] Figure 4 This is a schematic diagram of the connection of a line terminal module in a network framework according to an embodiment of this application.

[0035] Figure 5 This is a schematic diagram of a network terminal sending data and sharing memory storage provided in an embodiment of this application.

[0036] Figure 6 This is a schematic diagram illustrating the distance measurement between a clock master and various network terminals provided in an embodiment of this application.

[0037] Figure 7 This is a schematic diagram of a shared memory format sent by an end-system programmable logic device according to an embodiment of this application.

[0038] Figure 8 This is a schematic diagram of receiving a shared memory format provided in an embodiment of this application.

[0039] Figure 9 This is a schematic diagram of a shared memory format sent by an end-system programmable logic device according to an embodiment of this application.

[0040] Figure 10 This is a data receiving architecture block diagram of an end-system programmable logic device provided in an embodiment of this application. Detailed Implementation

[0041] The present application will now be further described in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments. The implementation process of the present application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in this specification. The present application can also be implemented or applied through other different specific implementation procedures, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be understood that the preferred embodiments are only for illustrating the present application and not for limiting the scope of protection of the present application.

[0042] The following is a brief description of the technical field and related terms of the embodiments of this application, so as to facilitate understanding by those skilled in the art.

[0043] RDIU stands for Remote Data Interface Unit. Distributed throughout the aircraft, these units collect data signals from sensors, process them, and transmit them to the aircraft's backbone network. They can also convert data from the application host and transmit it to remote actuators, enabling control of remote devices. Multiple RDIUs are typically used.

[0044] NIC: Short for Network Interface Card, it is a communication sub-card residing in the avionics system processing host of the integrated avionics platform, enabling data communication with the GPM of the integrated avionics platform. NICs consist of multiple network interface cards.

[0045] POS stands for Passive Optical Splitter. A splitter is an important passive optical device in fiber optic links. It can split a single optical signal into multiple optical signals or combine multiple optical signals into a single optical signal. A 1:32 splitter refers to a passive optical device that can evenly distribute one input optical signal into 32 outputs.

[0046] GPM is an abbreviation for General Processing Module, which is the processing module of the integrated avionics platform used to run resident system applications.

[0047] OLT: an abbreviation for Optical Line Terminal, is a data distribution and aggregation module of the integrated avionics platform. It is the core module for realizing the full network communication function of this integrated avionics system.

[0048] PSM is an abbreviation for Power Supply Module, which provides DC power to the GPM and OLT modules of the integrated avionics platform.

[0049] Cabinet: A cabinet provides the mechanical structure for mounting the GPM, OTL, and PSM modules of the integrated avionics platform, and provides backplane circuitry for necessary communication interconnection between the modules.

[0050] Network terminal: The end node of a communication network, used to send data to the network or receive data from the network. In the network architecture of this application, it refers to RDIU, NIC and GPM.

[0051] OLT_FPGA: The core processing device of the OLT module, which is an FPGA programmable logic design device.

[0052] ES_FPGA: End system device, which is an FPGA programmable logic design device used by various network terminals to access the network.

[0053] This application proposes a network architecture for an integrated avionics system based on a passive optical network. The architecture is simple, reliable, and flexibly configurable, improving system security and reliability, enhancing low-latency and high-deterministic performance requirements, and reducing network device size, weight, power consumption, and cost. The network architecture will be described first, followed by explanations of the methods, etc.

[0054] Network architecture implementation example.

[0055] This embodiment provides an integrated avionics system architecture based on a passive optical network (PON). The integrated avionics system architecture is used for the access of optical network terminal unit groups and includes:

[0056] The first optical splitter, the second optical splitter, and multiple general-purpose processing modules, the first optical line terminal and the second optical line terminal are installed in the first cabinet;

[0057] Each of the general processing modules is connected to the optical network terminal unit group through the first optical line terminal and the first beam splitter to form a first network; each of the general processing modules is connected to the optical network terminal unit group through the second optical line terminal and the second beam splitter to form a second network; the first network and the second network form a first dual-plane network group.

[0058] In this configuration, each network in the first dual-plane network group is configured to use a time-division multiple access protocol for bidirectional communication during the information transmission phase. The communication data is transmitted after being aggregated by the first optical line terminal and the second optical line terminal within a fixed time slot.

[0059] This technical solution proposes an integrated avionics system architecture based on passive optical networks. Its core lies in replacing the traditional Ethernet switching structure with a passive optical network to form a dual-plane redundant design structure. The above structure can apply the time division multiple access (TDMA) mechanism to achieve high security, high determinism, and low latency avionics data communication.

[0060] In the integrated avionics system architecture, the first and second optical splitters are passive optical devices used to distribute optical signals to multiple terminals or to converge them in reverse. The first cabinet houses multiple general purpose processing modules (GPMs), serving as the core data processing unit; it also includes a first optical line terminal and a second optical line terminal, each connecting to two independent networks. These two networks constitute the first dual-plane network group, with independent physical paths and no mutual interference.

[0061] Its communication mechanism is as follows: each network uses a time division multiple access (TDMA) protocol during communication; all communication data is transmitted within a fixed time slot; data is aggregated and distributed through an OLT to achieve bidirectional communication; due to the use of fixed time slot scheduling, data conflicts are avoided, ensuring the determinism and real-time nature of communication.

[0062] Simultaneously, each general-purpose processing module connects to the terminal unit group via two independent OLTs and optical splitters, forming two independent communication paths (a first network and a second network). It can be assumed that the same data can be transmitted simultaneously through both networks, supporting redundant communication to improve reliability. In practical applications, the receiving end can compare and verify the data from both paths, enhancing security.

[0063] The advantage of the technical solution provided in this embodiment is that, compared to related technologies where avionics networks rely on switching chips and suffer from latency and jitter, this solution employs a passive optical splitter and OLT structure, eliminating the need for switching chips and avoiding the latency and jitter introduced by switching. To address the lack of determinism in network communication, a TDMA protocol is introduced, ensuring data transmission within fixed time slots and guaranteeing controllable communication time and deterministic behavior. Considering the failure risk of single-path communication, a dual-plane network group is constructed, providing two independent communication paths to achieve path-level redundancy.

[0064] In summary, by constructing a dual-plane communication architecture based on passive optical networks and using a time-division multiple access protocol to achieve bidirectional data communication within a fixed time slot, the uncertainty problem caused by the switching chip is fundamentally avoided, and redundant communication paths are provided, thus realizing high determinism, high reliability, and low latency data transmission in avionics systems.

[0065] In some embodiments, a second dual-plane network group is further included; the second dual-plane network group includes a plurality of general-purpose processing modules, a third optical line terminal and a fourth optical line terminal disposed in a second cabinet, a third optical splitter disposed between the optical network terminal unit group and the third optical line terminal, and a fourth optical splitter disposed between the optical network terminal unit group and the fourth optical line terminal; the second dual-plane network group and the first dual-plane network group are mutually redundant backups.

[0066] The technical solution provided in this embodiment sets up a second dual-plane network group on the basis of the first dual-plane network group, forming a more complete redundancy backup structure. Specifically, the optical network terminal unit group is connected to the third optical line terminal through the third optical splitter and to the fourth optical line terminal through the fourth optical splitter, forming two independent communication paths and constituting the second dual-plane network group; the second dual-plane network group and the first dual-plane network group are redundant backups of each other.

[0067] In other words, the first dual-plane network group and the second dual-plane network group are physically independent; the two networks can operate simultaneously or switch between primary and backup; when a network group (such as the first group) fails, it can switch to the other group to continue communication, which is used to achieve dual redundancy and improve fault tolerance.

[0068] The advantage of the technical solution provided in this embodiment is that by introducing a second dual-plane network group, which forms a redundant rack-level structure with the first dual-plane network group, communication redundancy is achieved, significantly improving the reliability, availability and security of the avionics network system.

[0069] In some embodiments, the optical network terminal unit group includes multiple remote data interface units and multiple network interface cards; the first cabinet and the second cabinet are also respectively provided with power modules for supplying power to the processing module group and optical line terminal module in their respective cabinets.

[0070] Specifically, the optical network terminal unit group consists of the following two types of terminals:

[0071] Remote Data Interface Units (RDIUs), distributed throughout the aircraft, are responsible for collecting sensor data and transmitting it to the network, or receiving control commands to drive actuators. Network Interface Cards (NICs), for example, located in the avionics main unit or processing module, are used to enable data interaction between the main unit and the network. These two types of terminals can be understood as optical network terminal units within an optical network terminal unit group.

[0072] Meanwhile, each of the first and second racks is equipped with a Power Supply Module (PSM), and each PSM supplies power only to the General Purpose Processing Module (GPM) and Optical Line Terminal (OLT) within its rack. The PSM is bound to the rack, achieving localized power supply and preventing power supply across racks.

[0073] In practical applications, the number of connected RDIUs and NICs is 4, 8, 16, etc., and the optical splitter is a passive optical splitter that can meet the splitting ratio (1:8, 1:16, 1:32, etc.) required by the number of RDIUs and NICs. This embodiment does not impose any limitations on this.

[0074] In some embodiments, the power module includes a main power supply and a backup power supply for providing one-to-one backup power supply (within the same rack).

[0075] In some embodiments, the first, second, third, and fourth optical splitters are all passive optical splitters with a splitting ratio of 1:32. The number of general-purpose processing modules disposed in the first rack is 6, and the number of general-purpose processing modules disposed in the second rack is 6. The accessed optical network terminal unit group includes 16 remote data interface units and 16 network interface cards. The above configuration can meet the needs in most cases.

[0076] In some embodiments, an end system device is further included, which is connected to the second dual-plane network group and the first dual-plane network group, and the end system device is used to implement data redundancy and de-redundancy between the second dual-plane network group and the first dual-plane network group.

[0077] The technical solution provided in this embodiment utilizes an end system device to connect the first dual-plane network group and the second dual-plane network group, and acts as an interactive node across the network groups to realize data interaction and collaborative processing between the two network groups.

[0078] In some embodiments, the first optical line terminal, the second optical line terminal, the third optical line terminal, and the fourth optical line terminal each include a photoelectric conversion module and an optical line terminal field-programmable logic device.

[0079] In some embodiments, the integrated avionics system architecture further includes a third optical splitter and a third optical line terminal. The first dual-plane network group also includes a third network formed by connecting each of the general processing modules through the third optical line terminal, the third optical splitter, and the optical network terminal unit group. The receiving end can be configured to output instructions after verifying consistency through a voting mechanism (two out of three strategy), that is, to select the command data with the majority consensus through voting as the final control instruction for the optical network terminal unit group.

[0080] In some embodiments, optical line terminals in the same dual-plane network are interlocked and synchronized, with one acting as the clock master and the other as the clock slave and synchronized with the clock master.

[0081] Method implementation examples.

[0082] This embodiment provides a communication method for the integrated avionics system architecture described in any one of the network architecture embodiments, the method comprising:

[0083] During the information transmission phase, the first optical line terminal and the second optical line terminal use a time division multiple access protocol to allocate fixed time slots to each network terminal, and then distribute the data to the target terminal after aggregation.

[0084] In some embodiments, the method by which the first optical line terminal and the second optical line terminal aggregate data and then distribute it to the target terminal includes:

[0085] The remote data interface unit that acquires sensing information in the optical network terminal unit group is selected as the interface unit; the first optical line terminal receives the sensing information sent by the selected interface unit through the first optical splitter and sends it to the general processing module in the first cabinet; the second optical line terminal receives the sensing information sent by the selected interface unit through the second optical splitter and sends it to the general processing module in the first cabinet; the general processing module compares the consistency of the received sensing information, and if there is a discrepancy, it is discarded and an alarm message is generated.

[0086] The general processing module for sending command data is selected as the general processing module. The first optical line terminal receives the command data sent by the selected general processing module and transmits it to each remote data interface unit in the optical network terminal unit group via the first optical splitter. The second optical line terminal receives the command data sent by the selected general processing module and transmits it to each remote data interface unit in the optical network terminal unit group via the second optical splitter. The remote data interface units in the optical network terminal unit group compare the consistency of the received command data; if there is a discrepancy, the data is discarded and an alarm message is generated. The technical solution provided in this embodiment utilizes a dual-plane passive optical network and TDMA time slot control to achieve redundant transmission and reception and consistency verification at the data layer, thereby achieving highly deterministic and highly secure two-way avionics communication with a minimal hardware structure (no switching chip).

[0087] In some embodiments, optical line terminals in the same dual-plane network are interlocked and synchronized, with one acting as a clock master and the other as a clock slave and synchronized with the clock master. The method further includes: using the clock master to send clock information to all network terminals in the network to achieve network-wide clock synchronization.

[0088] The optical line terminal periodically sends clock information to all network terminals (RDIU, NIC, GPM); this clock information can be transmitted through a dedicated synchronization message or embedded in the data frame header; all terminals receive the same clock reference as the time reference for local time slot timing and data sampling.

[0089] Each network terminal adjusts its local clock counter based on the received clock information; ensures that the time slot boundaries, transmission times, and reception windows of all terminals are aligned under the same time base; provides a global time base for the Time Division Multiple Access (TDMA) mechanism, and ensures that no conflicts occur during data aggregation.

[0090] In some embodiments, optical line terminals in the same dual-plane network are interlocked and synchronized, with one acting as a clock master and the other as a clock slave and synchronized with the clock master. The method further includes: using the clock master to send clock information to all network terminals in the network to achieve network-wide clock synchronization.

[0091] In practical applications, the clock master can be determined through power-on negotiation, priority comparison, or preset configuration. The clock master uses its local clock as a reference and periodically sends synchronization messages (including the master's timestamp) to the clock slaves. Upon receiving these messages, the clock slaves calculate the transmission delay and adjust their local clocks to match the master's clock. Simultaneously, the clock master broadcasts clock information to all network terminals (RDIU / NIC / GPM). The network terminals then correct their local clocks based on the received time and the master's timestamp, thus completing network-wide clock synchronization.

[0092] To facilitate understanding, an example of a network architecture and implementation method for an integrated avionics system based on a passive optical network is provided. The architecture includes: two cabinets, each containing six general purpose processing modules (GPM), two optical line terminal modules (OLT), two power supply modules (PSM), and corresponding four passive optical splitters, 16 remote data interface units (RDIU), and 16 network interface cards (NIC).

[0093] This communication network configuration supports the network requirements of the integrated avionics platform for large civil aircraft. It employs a dual-network system design for redundancy and backup. Each network consists of: one cabinet, six general purpose processing modules (GPMs), two optical line terminal modules (OLTs), two power supply modules (PSMs), and two passive optical splitters (1:32). Each network simultaneously supports the access of all 16 remote data interface units (RDIUs) and 16 network interface cards (NICs).

[0094] In practical applications, for specific aircraft models, taking the electric vertical takeoff and landing (eVTOL) aircraft as an example, the number of sensors and actuators is significantly reduced, which in turn significantly reduces the number of network terminals. This allows for tailoring the network architecture configuration, further reducing costs and weight. For instance, for a network configuration requiring 8 Remote Data Interface Units (RDIUs) and 8 Network Interface Cards (NICs), the network architecture configuration can be tailored to: 2 cabinets, each containing 2 General Purpose Processing Modules (GPMs), 2 Optical Line Terminal Modules (OLTs), and 2 Power Supply Modules (PSMs); and 4 passive optical splitters (1:16).

[0095] It can be argued that, based on the high bandwidth characteristics of optical networks, the use of Time Division Multiple Access (TDMA) technology enables the aggregation and transmission of data from various network terminals, eliminating the need for network switching chips, completely preventing the deterioration of latency and jitter caused by network switching, and significantly reducing network complexity and costs.

[0096] Furthermore, the optical line terminal periodically sends time synchronization messages across the entire network to achieve network-wide clock synchronization, thereby supporting deterministic data transmission.

[0097] By measuring distances, each network terminal can accurately adjust its network time, eliminating transmission delay differences caused by varying distances between the OLT and different network terminals. This allows for more precise time synchronization across the entire network and better guarantees the determinism of data transmission.

[0098] The network terminal module achieves network access through an end-system programmable logic device. The end-system design supports the requirements of the aerospace ARINC 653 operating system, and data interaction with the software uses a shared memory approach. The end system adopts a parameter-configurable approach, achieving a unique design that simultaneously supports RDIU, NIC, and GPM, and adapts to different hardware resources and computing power requirements.

[0099] Data transfer between the various system processing units of the aircraft and the integrated avionics general processing module can be accomplished through a network interface card (NIC).

[0100] See Figure 1 This paper presents a schematic diagram of an integrated avionics system architecture based on passive optical networks.

[0101] Its architecture is configured as follows: two cabinets, each housing six General Purpose Processing Modules (GPMs), two Optical Line Terminal Modules (OLTs), and two Power Supply Modules (PSMs), as well as four passive optical splitters (1:32). This architecture supports network access for 16 Remote Data Interface Units (RDIUs) and 16 Network Interface Cards (NICs). The RDIUs also connect to sensors and actuators.

[0102] based on Figure 1 The architecture configuration shown enables data aggregation and transmission from various network terminals, thereby achieving network data exchange without the need for network switching chips. It employs Time Division Multiple Access (TDMA) technology, where each network terminal occupies a fixed time slot for data aggregation at the optical line terminal before transmission, ensuring high determinism in data transmission. At the same time, the high bandwidth of optical transmission ensures low latency.

[0103] based on Figure 1 The architecture shown constructs a dual-network system with primary and backup. Each network is configured with: 1 cabinet, 6 general purpose processing modules (GPM), 2 optical line terminal modules (OLT), 2 power supply modules (PSM), and 2 passive optical splitters (1:32). Each network simultaneously supports the access of all 16 remote data interface units (RDIU) and 16 network interface cards (NIC). When the primary network fails, it switches to the backup network in real time.

[0104] Meanwhile, for each network, a dual-plane network is achieved by providing two optical line terminal modules and two passive optical splitters, providing a fully redundant network path. The dual-plane data traffic does not overlap, and redundancy and deduplication are only achieved at the end system.

[0105] See Figure 2 This paper presents a schematic diagram illustrating the communication transmission of sensor data from a remote data interface unit (RDIU) to a general-purpose processing module. The data collected by the sensor is processed and encapsulated by the RDIU, then copied into four identical copies and simultaneously transmitted to two networks through four different ports. For each network, the data is sent to a different 1:32 optical splitter via two different ports, and then to a different OLT, thus enabling the transmission of data from the same RDIU through different network paths. After receiving the identical RDIU data from the two OLTs, the GPM performs real-time data comparison; if the data is identical, it is accepted; otherwise, it is discarded and an alarm is triggered.

[0106] See Figure 3This paper presents a schematic diagram illustrating the communication transmission of actuator data from a general-purpose processing module to a remote data interface unit. The application program of the GPM-resident system copies command data into two identical copies and sends them simultaneously to two OLTs via different ports. These copies are then sent to two different ports of the same RDIU via corresponding 1:32 optical splitters, thus enabling the transmission of command data from the same GPM through different network paths. Upon receiving identical data from the two different ports, the RDIU performs real-time data comparison. If the data is identical, it is accepted; otherwise, it is discarded and an alarm is triggered.

[0107] See Figure 4 This paper presents a schematic diagram illustrating the connection of a line terminal module within a network framework. A dual-plane network is implemented using two OLT modules and two optical splitters, with data transmission between network terminals via redundant paths.

[0108] In the communication direction from RDIU or NIC to GPM, a 1:32 optical splitter achieves data aggregation. TDMA technology is used to transmit data from each RDIU (Remote Data Interface Unit 0 to Remote Data Interface Unit 15) and NIC (Network Interface Card 0 to Network Interface Card 15) through one or more fixed time slots. The aggregated data frame format (Optical Line Terminal Aggregation Frame Format) is as follows: Figure 5 As shown in the diagram, the aggregated data frames are transmitted via optical fiber to the OLT (Optical Line Terminal 0 and Optical Line Terminal 1). The OLT includes a photoelectric conversion module and an optical line terminal field-programmable logic device (OLT_FPGA). The photoelectric conversion module converts the aggregated data frames into electrical signals, which are then copied in the OLT_FPGA and sent to the connection ports (ChA, ChB) of each GPM (General Processing Module 1 to General Processing Module 6). Each remote data interface unit connects to different splitters through different connection ports (ChA, ChB, ChC, ChD) and transmits the data to Optical Line Terminal 0 and Optical Line Terminal 1. Some connections are omitted in the diagram.

[0109] In the communication mode from GPM to RDIU or NIC, OLT realizes data aggregation. OLT_FPGA uses TDMA technology to aggregate the data of each GPM through one or more fixed time slots. After aggregation, the data frame is converted into an optical signal by the photoelectric conversion module, sent to the optical splitter through the optical fiber, and then distributed by the optical splitter into 32 identical copies and sent to 16 RDIU and 16 NIC modules respectively.

[0110] To achieve clock synchronization within the network, the OLT periodically sends clock information to all terminals across the network. Each network terminal operates under a unified clock, ensuring that the allocated time slots are accurately occupied when terminal data is aggregated without causing conflicts. At the same time, it ensures that the time is precisely aligned when data is distributed to two different receiving ports of the same terminal, thereby achieving the function of lockstep. The receiving end strictly compares the data from the two ports and they must be completely consistent.

[0111] A network has two optical line terminals (OLTs) that use an interlocked synchronization method. The module that acquires priority becomes the clock master, and the other module acts as the clock slave, synchronizing with the master. Considering the differences in path length between the OLTs and other network terminals, handshake messages are sent by the OLTs to measure their distances to each network terminal. This allows for more accurate time synchronization across the entire network, addressing the transmission delay differences caused by varying distances between network terminals, and better ensuring the determinism of data transmission.

[0112] See Figure 6 This paper presents a schematic diagram for measuring the distance between a clock master and various network terminals. The clock master first sends a Sync message to the network terminal at time t1, and the network terminal receives this message at time t2. Subsequently, the clock master sends the time t1 to the network terminal via a Follow_Up message. A Delay_Req message is sent by the network terminal to the clock master after receiving the Sync message, at time t3. Upon receiving this message, the clock master sends the accurate reception time t4 to the network terminal via a Delay_Resp message. The path delay between the clock master and the network terminal is thus obtained, corresponding to the following formula: PathDelay = [(t2–t1) + (t4–t3)] / 2. PathDelay represents the path delay data.

[0113] In practical applications, the propagation delay of light in optical fiber is approximately 5 ns / m. Factors such as changes in ambient temperature and device aging can also cause delay drift. Temperature changes primarily affect the physical length and refractive index of the optical fiber, thus altering the propagation delay. However, this effect is extremely small and negligible for network deployments on aircraft. Device aging is also negligible for a single flight. Therefore, a single static measurement of the distance between the clock master and each network terminal can be performed during the power-on self-test of the integrated avionics platform.

[0114] Meanwhile, all network terminals provided in this example, including RDIU, NIC, and GPM, need to achieve network access through an end system. This end system will be implemented using a Field-Programmable Array (FPGA) to provide powerful data processing capabilities and achieve low-latency and high-determinism data transmission. This end system programmable logic device is abbreviated as ES_FPGA.

[0115] ES_FPGA will adopt a unified design to adapt to various application scenarios of all network terminals. It will use shared memory to interact with the software residing on the module and support the requirements of the aviation ARINC 653 operating system. The parameters for the number of concurrent messages and the storage space rules for a single message will be configurable.

[0116] See Figure 7 This diagram illustrates the shared memory format transmitted by end-system programmable logic devices. VL stands for Virtual Link, representing the destination network terminal. The illustrated example supports 64 VLs, but the number of VLs is configurable in practice. Each VL supports four Sub-Virtual Links (SVLs), which are transmitted in a round-robin fashion. Only one SVL can be transmitted at a time. In the illustrated example, each SVL is allocated four 8KB buffers in shared memory. In practice, the size of each buffer can vary and is allocated by software based on the actual data volume. The header 8 bytes of each transmit buffer contain the SVL number, the payload length, the COM port number, and necessary flags.

[0117] Optical network transmission can achieve high-bandwidth data transmission. Considering product cost and power consumption, a transmission bandwidth of 2.5Gbps can be selected. Figure 5 The example shown uses an even distribution of time slots, requiring a total of 32 time slots. Each time slot has a maximum transmission bandwidth of 2500 / 32 = 78.125 Mbps, far exceeding the actual data transmission bandwidth requirements of each network terminal. If each time slot transmits 1518 bytes of data, the time per time slot is 1518*8 / 2500 = 4.8576 µs, resulting in very low network latency. Figure 5 The time slot allocation in the example shown can be parameterized in actual products. A network terminal can occupy one or more time slots, and the fixed data length transmitted in each time slot can be parameterized.

[0118] See Figure 9This document provides a data transmission architecture block diagram for end-system programmable logic devices, including a transmission configuration module, a status reporting module, a transmission data monitoring module, a transmission scheduling module, a network clock synchronization module, a time slot management module, a transmission decision module, a data acquisition module, and a data transmission module. The ES_FPGA monitors the existence of transmission data in shared memory through a software-defined information interaction mechanism. When multiple Virtual Levels (VLs) have transmission data requirements, or when a single VL has multiple SVLs (Segmented Virtual Levels) with transmission requests, a polling method is used for transmission scheduling. Based on the clock master module, a clock is issued and corrected according to the distance between the clock master module and the terminal to achieve accurate network clock synchronization. The time slot management indication signal of the terminal is obtained based on the configuration data. Combining the output of the transmission scheduling and the time slot management output signal, a transmission decision command is obtained, determining the VL and SVL to be transmitted. The data acquisition module obtains the transmission data block address by searching the configuration data based on the VL and SVL to be transmitted, reads the data from RAM, and then transmits the data. The data packet is simultaneously sent to the first and second networks through the first network transmission port and the second network transmission port.

[0119] Since there is no network switching, all data transmitted by network terminals is aggregated in fixed time slots according to configuration requirements and then sent to each receiving terminal. Therefore, there is no need to modify or encapsulate the data in the shared memory transmit buffer block. In practical applications, when the data length in the buffer block exceeds the data length that a time slot can transmit, the data needs to be fragmented into multiple data packets for transmission, and then reassembled at the receiving terminal.

[0120] The network terminal receiving data will receive the same data from two different network ports. Due to the network-wide clock synchronization and the deterministic nature of data transmission, the receiving end will directly compare the two data streams in real time. If they differ, the data will be discarded and an alarm will be triggered. The received data is stored in the receive shared memory, and the receive shared memory format is as follows: Figure 8 As shown. Data is stored according to the destination port number (Dst Port). Each destination port number is allocated 4 receive buffer blocks, and each buffer block has the same depth and is configurable. Figure 8 In the example shown, each storage block is 8KB deep.

[0121] When receiving data, each network terminal selects the data according to the VL number and communication port number configured in the receiving configuration table, and determines the destination port number and the address of the buffer block to be stored according to the corresponding relationship in the receiving configuration table. When storing data, the communication port number is changed to the destination port number, while the rest of the data content remains unchanged.

[0122] The format of the received configuration table is as follows:

[0123] VL number COM Port Dst Port First cache block address Cache block depth

[0124] See Figure 10 It provides a data receiving architecture block diagram for end system programmable logic devices, including a receiving configuration module, a status reporting module, a first network receiving filter module, a second network receiving filter module, a data comparison module, and a data storage control module. The data storage control module is connected to RAM (random access memory).

[0125] The converged frame data enters the ES_FPGA from two ports, each then enters its corresponding receive filtering module. This module filters out packets whose VL number and COM Port combination are not recorded in the receive configuration table. The filtered packets are the packets that the network terminal needs to receive, and they must be completely identical in real-time. Otherwise, an error is recorded in the status data. After comparing the correct data, the destination port number and corresponding storage address are obtained by looking up the receive configuration table. The data is then stored in the receive buffer block of shared memory, thus completing the data reception.

[0126] Storage medium example.

[0127] This embodiment provides a computer-readable storage medium, the specific embodiments of which are consistent with the embodiments described in the above method embodiments and the technical effects achieved are the same, and some contents will not be repeated. A computer program is stored thereon, and when the computer program is executed by at least one processor, it implements the steps of any of the methods described above.

[0128] Example of a program product.

[0129] This embodiment provides a computer program product, the specific embodiments of which are consistent with the embodiments described in the above method embodiments and achieve the same technical effects, and some contents will not be repeated. The computer program product includes a computer program, which, when executed by at least one processor, implements the steps of any of the methods described above.

[0130] It should be noted that in the embodiments of this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple. It is worth noting that "at least one" can also be interpreted as "one or more".

[0131] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are configured to distinguish similar objects and are not necessarily configured to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0132] This application describes the invention from the perspectives of purpose, performance, progress, and novelty, and it meets the functional enhancement and use requirements emphasized by the Patent Law. The above description and drawings are merely preferred embodiments of this application and are not intended to limit this application. Therefore, all structures, devices, features, etc., that are similar to or identical to those of this application, i.e., all equivalent substitutions or modifications made in accordance with the scope of this patent application, shall fall within the scope of protection of this patent application.

Claims

1. An integrated avionics system architecture based on passive optical networks, characterized in that, The integrated avionics system architecture is used for the access of optical network terminal unit groups, and the integrated avionics system architecture includes: The first optical splitter, the second optical splitter, and multiple general-purpose processing modules, the first optical line terminal and the second optical line terminal are installed in the first cabinet; Each of the general processing modules is connected to the optical network terminal unit group through the first optical line terminal and the first beam splitter to form a first network; each of the general processing modules is connected to the optical network terminal unit group through the second optical line terminal and the second beam splitter to form a second network; the first network and the second network form a first dual-plane network group.

2. The integrated avionics system architecture according to claim 1, characterized in that, It also includes a second dual-plane network group; the second dual-plane network group includes multiple general-purpose processing modules, a third optical line terminal and a fourth optical line terminal disposed in the second cabinet, as well as a third optical splitter disposed between the optical network terminal unit group and the third optical line terminal, and a fourth optical splitter disposed between the optical network terminal unit group and the fourth optical line terminal; the second dual-plane network group and the first dual-plane network group are mutually redundant backups.

3. The integrated avionics system architecture according to claim 2, characterized in that, It also includes end system devices, which are connected to the second dual-plane network group and the first dual-plane network group. The end system devices are used to realize data redundancy and de-redundancy between the second dual-plane network group and the first dual-plane network group.

4. The integrated avionics system architecture according to claim 2, characterized in that, The first optical line terminal, the second optical line terminal, the third optical line terminal, and the fourth optical line terminal all include a photoelectric conversion module and an optical line terminal field-programmable logic device.

5. The integrated avionics system architecture according to claim 2, characterized in that, The optical network terminal unit group includes multiple remote data interface units and multiple network interface cards.

6. The integrated avionics system architecture according to claim 5, characterized in that, The first, second, third, and fourth optical splitters are all passive optical splitters with a splitting ratio of 1:

32. The number of general-purpose processing modules installed in the first cabinet is 6, and the number of general-purpose processing modules installed in the second cabinet is 6. The connected optical network terminal unit group includes 16 remote data interface units and 16 network interface cards.

7. The integrated avionics system architecture according to claim 5, characterized in that, The integrated avionics system architecture is used for electric vertical takeoff and landing aircraft. The first, second, third, and fourth beam splitters are all passive beam splitters with a splitting ratio of 1:

16. The number of general-purpose processing modules installed in the first cabinet is 2, and the number of general-purpose processing modules installed in the second cabinet is 2. The connected optical network terminal unit group includes 8 remote data interface units and 8 network interface cards.

8. The integrated avionics system architecture according to claim 2, characterized in that, The first and second cabinets are also equipped with power modules to supply power to the processing module group and optical line terminal module in their respective cabinets.

9. The integrated avionics system architecture according to claim 8, characterized in that, The power module includes a main power supply and a backup power supply, which are used to provide power for both main and backup applications.

10. The integrated avionics system architecture according to claim 1, characterized in that, The integrated avionics system architecture also includes a third optical splitter and a third optical line terminal. The first dual-plane network group also includes a third network formed by connecting each of the general processing modules through the third optical line terminal, the third optical splitter and the optical network terminal unit group.

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