Modular Avionics Research Articles

Optimal Design of Configuration Scheme for Integrated Modular Avionics Systems With Functional Redundancy Requirements

Integrated modular avionics architecture has become the most attractive idea to enhance system capability as well as improve efficiency. However, this architecture makes designing a system configuration scheme difficult because multiple resources are shared to support different functions that may have been irrelevant before. This article introduces a method to optimize the configuration scheme for an integrated modular avionics system while considering functional redundancy requirements. Not only the allocation scheme, which illustrates the relationships between functions and shared resources is taken into account, but also the resource scheme, which illustrates how many shared resources are enough to cover the functional requirements is considered as a part of the configuration scheme. Toward a generic integrated modular avionics system with functional redundancy requirements, we first give a configuration scheme model as well as its related schedulability and reliability constraints. Then, the optimization process of the configuration scheme is formalized as a combination of a constraint satisfaction problem and a constraint optimization problem. Specifically, it is decomposed into two steps including: 1) finding a resource scheme which has the lowest cost but still satisfies the constraints based on a forward checking algorithm; 2) finding its corresponding allocation scheme which distributes the targeted functions to different resources as evenly and low-coupled as possible based on the NSGA-II algorithm. Finally, an example is used to prove the effectiveness of the method. The optimization method can serve as a guide to design a configuration scheme for the integrated modular avionics system.

New Model-Based Analysis Method with Multiple Constraints for Integrated Modular Avionics Dynamic Reconfiguration Process

With the development of integrated modular avionics (IMA), the dynamic reconfiguration of IMA not only provides great advantages in resource utilization and aircraft configuration, but also acts as a valid means for resource failure management. It is vital to ensure the correction of the IMA dynamic reconfiguration process. The analysis of the dynamic reconfiguration process is a significant task. The Architecture Analysis & Design Language (AADL) is widely used in complicated real-time embedded systems. The language can describe the system configuration and the execution behaviors, such as configuration changes. Petri net is a widely used tool to conduct simulation analysis in many aspects. In this study, a model-based analyzing method with multiple constraints for the IMA dynamic reconfiguration process was proposed. First, several design constraints on the process were investigated. Second, the dynamic reconfiguration process was modeled based on the AADL. Then, a set of rules for the transition of the model from AADL to Petri net was generated, and the multi-constraints proposed were incorporated into Petri net for analysis. Finally, a simulation multi-constraint analysis with Petri net for the process of IMA dynamic reconfiguration was conducted. Finally, a case study was employed to demonstrate this method. This method is advantageous to the validity of IMA dynamic reconfiguration at the beginning of the system design.

Head-up display architecture development for perspective civil aircraft

Nowadays the civil aircraft head-up displays available on the market could not be easily integrated onboard due to architectural aspects. Particularly, these systems usually contain a dedicated computer unit performing the data processing to generate the appropriate image. This leads to increases in the overall avionics weight and size and limits the scope of head-up displays application in general. However, the mentioned characteristics could be improved by the usage of the integrated modular avionics concept for architecture design. According to that approach, the common hardware platform is used by different functional consumers to share computation resources. Thus, the required data processing function could be performed by the equipment already available onboard (without the need in additional hardware). The paper proposes the head-up display architecture for civil aircraft based on integrated modular avionics which significantly reduces the system’s weight and size compared to characteristics of existing analogous. Also, this way allows reducing the time expenses for aircraft development, testing and certification, as well as the vehicle operational cost.

A Survey of Optimal Hardware and Software Mapping for Distributed Integrated Modular Avionics Systems

With an increasing number of aircraft systems, a fully manual developmental approach is impractical for finding optimal hardware and software mapping from overwhelming configurations for Distributed Integrated Modular Avionics (DIMA) systems. The automation of finding such optimized mapping should be available and thoroughly understood. This paper is an investigation on the foundations of optimal hardware and software mapping for DIMA. We begin by reviewing the DIMA system architecture. Following that, we present the problem statement of hardware and software mapping and its ensuring mathematical optimization models. A set of primary architectural quality metrics (e.g., reliability and scalability) and aircraft constraints (e.g., segregation and resource constraints) are identified, which can be used to compose an objective function or compare and trade alternatives. Based on the quality metrics and aircraft constraints, we synthesize an encompassing formulation by means of multi-objective optimization. Various optimization approaches for hardware and software mapping are then reviewed and compared. Case studies of DIMA optimization are presented for avionics systems, in which running time is reported for different optimization problems with different objectives and constraints. In addition, we present and discuss open issues and future trends, from which future developments may draw upon.

Research on Partition Parameter Design Method for Integrated Modular Avionics Based on MOEA/D-ADV

In the avionics industry, Integrated Modular Avionics (IMA) which introduces the concept of partition has been widely adopted for its isolating capability. However, the real-time performance of the IMA system mainly depends on the partition parameters. This leads to the question of how to design the partition parameters for satisfying the timing requirements of real-time applications. In this paper, the problem of partition parameter design for multiprocessors system is investigated. Firstly, the hierarchical scheduling strategy of IMA is analyzed, and a new schedulability analysis method is proposed to judge the schedulability of the partitions according to the partition period and execution time. Then, an approximation algorithm is developed to minimize the allocated bandwidth of the partitions while simultaneously guaranteeing tasks schedulability within the partitions. The harmonic period partitions, which are used as the constraint of partition parameter design, are realized by considering the scheduling mechanism of intra-partition and inter-partition. The total required bandwidth and the system overhead caused by partition scheduling are regarded as the optimization objective functions. Moreover, Multi-objective Evolutionary Algorithm Based on Decomposition (MOEA/D) method is improved by applying the Adjustment for the Direction Vectors (ADV) algorithm. Constrained Dominance Principle (CDP) is embedded into the improved algorithm to solve the constrained optimization problem. Consequently, simulation results show that the presented algorithm can achieve better coverage and uniformity than the compared algorithms while obtaining the partition parameters, and the system overhead and total required bandwidth can also be reduced.

Independent Temporal Integration of ARINC653 Conformed Architecture — A Search Based Solution

ARINC653-based integrated modular avionics (IMA) architecture has been widely adopted in the design of modern civil and military aircraft. IMA imposes various requirements on the underlying operating system, of which the temporal and spatial separation requirements are essential to task allocation. In practice, finding the optimal allocation configurations of tasks to enable processing modules to satisfy various temporal constraints is one of the greatest challenges. For that purpose, hundreds of tasks must be mapped into given processing modules, which has been proven to be a nonpolynomial problem. This paper introduces a search-based approach to aid in finding effective solutions for the task allocation problem in polynomial time. Two search techniques based on both population search (genetic algorithm) and neighbor search (simulated annealing), along with their multicore versions, are presented. A heuristic is designed specifically to validate whether candidate solutions fulfill various constraints implied by IMA, and thus to evaluate the fitness. Furthermore, the multicore version is designed to reduce the time delay of obtaining a new optimized configuration. The results show that both algorithms can ultimately find optimized solutions with utility rates above 90% in all configurations and can support the optimization over 100 tasks, which is an outstanding result. The result also reveals that simulated annealing can produce a better solution under limited resources, while the genetic algorithm will determine a valid solution within a shorter time period. Moreover, simulated annealing outperforms the genetic algorithm in terms of both effectiveness and efficiency with respect to solving this allocation problem with complicated constraints.

Reliability of Software Applications in Integrated Modular Avionics

The integrated modular avionics (IMA) network consists of a number of computing modules capable of supporting numerous applications of differing critical and non-critical levels. In opposition to traditional hardware-oriented architectures, the IMA concept proposes an integrated software-oriented architecture with application software portable across an assembly of common hardware modules. IMA allows focusing on running applications instead of managing infrastructure. The IMA software runs in a certain partition (container). In practice, when organizing partition-based access to applications, it is important to know the availability of a separate dedicated container with application in active operation. In this case if the failure of another service for another application has come, for this particular IMA partition such failure in another partition from the position of reliability is not critical. In the article the availability of a dedicated IMA container in the system with partition-based IMA architecture is studied. The mathematical model of the reliability of a separate dedicated container with active application in the real conditions of operation is developed. Expressions for availability of application operation in dedicated IMA container are developed.

Large-Scale Model-Based Avionics Architecture Optimization Methods and Case Study

This paper presents a model-driven multiobjective avionics system optimization method developed over six years at its final destination, the application in real-world integrated modular avionics systems. It documents the methods, the application scenario, and the results of large-scale optimization studies carried out for the Airbus A350 peripheral acquisition system. The results predict that a significantly lighter system could be possible.

Parameter Generation for Hierarchical Scheduling Systems Based on Model Checking

A parameter generation method based on model checking is proposed to tackle the parameter selection of hierarchical scheduling systems in Integrated Modular Avionics (IMA) by combining the classical symbolic model checking and the Statistical Model Checking (SMC). It builds a generic timed automata network to describe the temporal behavior of hierarchical systems. A distributed genetic algorithm is adopted to search the optimum partition parameters with respect to processor utilization while guaranteeing the schedulability of the system, which is formulated as safety properties of symbolic model checking and hypothesis testing of SMC. Comparing with the widely-used response time analysis, the formal model of this method is more expressive to cover complex features. The application of SMC alleviates the "state space explosion" of classical model checking. Finally, the parameter generation experiments show that the present method is able to find the global optimum solutions in the parameter space.

Virtual Integration in Avionics Systems‐RTOS

AbstractThis paper discuss about the challenges and thoughts in Virtual integration using Real Time Operating Systems for avionics system integration with respect to different architectures like Open System Architecture and Integrated Modular Avionics.This paper mainly discusses about role of RTOS like ARINC653 in solving the problems in Avionics System Engineering, in which software‐software integration and hardware‐software integration is achieved using features of RTOS and this approach is called Virtual Integration. I have proposed customization of existing RTOS using new concepts which enhances the capability of performance and extendibility in integration keeping core System Engineering Principles in mind.This paper discusses about the system integration challenges identified in use of existing RTOS which includes: 1. Cross Platform Development, 2. Selection of communication mechanisms and scheduling for mixed operating system environment, 3. Current RTOS are mainly Monolithic and Micro Kernel based to compete in speed of execution and process management. 4. Current RTOS are limited to target platforms like Power PC, Intel x86 etc. and not supporting soft processors like micro‐blaze, FPGA platforms etc.Proposal for future enhancements to include use of Kernel level scheduling algorithms and Nano Kernels in RTOS to host more Platform OS to have more number of independent process running with more accurate time scheduling with less switch overheads, support for cross platform development with different host development technologies, support for SOC, POC other than conventional processors like x86, Power PC, ARM and MIPS etc.This paper discusses about the Network Virtualization and its application in avionics integration to overcome the capability of hardware networking devices using RTOS. Applying Trusted Execution Technology (TXT) approach in Integrated Modular Avionics (IMA) to ensure that the launching components at BIOS, OS Loader and Hypervisor are safe and trusted to avoid failure and malfunctions during run‐time.

Design of onboard data server for the implementation as a part of onboard avionics equipment using concept of integrated modular avionics

Modern onboard equipment (OBE) includes systems that require storage and processing of large amount of information. At the same time real-time access to data is required. On the samples of national aircrafts, information is most often stored in computers, where the main functions are not data storage, but data processing. Most of the computing resources are spent on running applications. This results in slow processing of requests to a database (DB), which in turn affects the speed of systems that need data from the database or that keep records to the database. The article is devoted to the development of Onboard Data server (ODS) using the concept of integrated modular avionics (IMA) for the onboard avionics equipment of medium-range MS-21 aircraft. ODS is a separate data server computing platform, which provides running of several independent functional applications and carrying out interaction with onboard equipment via AFDX, USB, Ethernet, RS-232 interfaces. The article provides the requirements for the Onboard Data Server, software requirements, architecture, calculation of reliability indicators, four modes of operation: start mode, operating mode, extended control mode and technological mode, describes the algorithm of transition between the modes of operation of the ODS. The use of the ODS will allow reducing the load on the computers of the functional applications of the aircraft systems, simplifying the work of the ground crew interacting with the onboard maintenance system and the aircraft crew, which prepares the flight plan using the navigation data processed on the server.

Safety Assessment Process Optimization for Integrated Modular Avionics

In order to evaluate the safety impacts introduced by the additional interactions between the software partition and the integrated modular avionics platform, an optimized safety assessment process is proposed to address the software partition specific failure mode, quantitative failure rate budget allocation, software reliability verification, and feedback to higher level safety assessment. With a case study based on an airborne datalink system, the optimized safety assessment process is discussed in detail, including the specific failure condition and corresponding preventive/corrective actions, the allocation and verification of software partition failure rate, as well as the feedback channel of these partition software failure rate to item/function failure mode and effect assessment. A reliability framework of partition software is also presented to support the reliability verification of partition software. The methodology is applicable to other IMA-based avionics system.

Application of distributed integrated modular avionics concept for perspective aircraft equipment control systems

The paper considers the possibility of distributed integrated modular avionics concept application for control systems of aircraft equipment. This approach allows reducing the cable network weight and size, reducing the noise of transmitted data, increasing the system reliability, shortening the time of the development and further modernization. As a result, the design of system and component part is proposed.

Benchmarking Analysis and Characterization of Hypervisors for Space Multicore Systems

Multicore systems are becoming widely diffused in the space domain, mainly because of the opportunities to improve performance and, at the same time, to optimize orthogonal metrics (e.g., cost, power consumption). However, the need to consider safety integrity levels, dictated by the relevant standards (i.e., ECSS-Q-ST-80C, ECSSQ-ST-30, ECSSQ-ST-40C, NPD 8700.1E, NPR 8715.3D, JMR-001, OST 134-1021-99), into space applications adds further challenges. In fact, in a multicore system, multiple processing cores share various resources; therefore, the implementation of modern and complex integrated modular avionics systems is problematic. Actually, integrated modular avionics systems are inherently mixed-critical ones where spatial and temporal isolation in the shared resources access is essential. As a way to mitigate such a problem, the exploitation of virtualization technologies allows to guarantee isolation and certification requirements but, at the same time, introduces scheduling overhead and new issues. The selection of the best virtualization technology is just one part of the solution. Then, further benchmarking and validation activities should help developers to certify virtualized environments running on multicore architectures. In such a context, this work proposes a methodology for characterization of hypervisor technologies in the space domain. Experimental results obtained by applying the proposed methodology in order to characterize some reference hypervisors features close the paper.

Schedulability Analysis of Distributed Multicore Avionics Systems with UPPAAL

This paper presents an approach for schedulability analysis of Distributed Integrated Modular Avionics (DIMA) systems that consist of spatially distributed ARINC-653 multicore modules connected by a unified Avionics Full-Duplex Switched Ethernet (AFDX) network. A multicore DIMA system is modeled as a set of stopwatch automata in uppaal to verify its schedulability by model checking. However, direct verification is infeasible due to the large state space. Therefore, global analysis based on statistical model checking (SMC) and compositional analysis based on classical model checking are combined, thereby mitigating the state space explosion problem. Even though the nature of SMC testing cannot prove schedulability, the model of a DIMA system first undergoes quick schedulability falsification using global SMC analysis. Thereafter, a compositional approach is used to check each partition, including its communication environment individually. By using assume-guarantee reasoning, it is ensured that each real-time task meets the deadline and that communication constraints are also fulfilled globally. The approach is finally applied to the schedulability analysis of a concrete multicore DIMA system.

Hybrid partition- and network-level scheduling design for distributed integrated modular avionics systems

Distributed Integrated Modular Avionics (DIMA) develops from Integrated Modular Avionics (IMA) and realizes distributed integration of multiple sub-function areas. Time-triggered network provides effective support for time synchronization and information coordination in DIMA systems. However, inconsistency between processing resources and communication network destroys the time determinism benefiting from partitions and time-triggered mechanism. To ensure such time determinism and achieve guaranteed real-time performance, system design should collectively provide a global communication scheme for messages in network domain and a corresponding execution scheme for partitions in processing domain. This paper firstly establishes a general DIMA model which coordinates partitioned processing and time-triggered communication, and then proposes a hybrid scheduling algorithm using Mixed Integer Programming to produce feasible system schemes. Furthermore, incrementally integrating new functions causes upgrades or reconfigurations of DIMA systems and will generate integration cost. To control such cost, this paper further develops an optimization algorithm based on Maximum Satisfiability Problem and guarantees that the scheduling design for upgraded DIMA systems inherit their original schemes as much as possible. Finally, two typical cases, including a simple fully connected DIMA system case and an industrial DIMA system case, are constructed to illustrate our DIMA model and validate the effectiveness of our hybrid scheduling algorithms.

A real-time on-chip network architecture for mixed criticality aerospace systems

ABSTRACTIntegrated Modular Avionics enables applications of different criticality levels to share the same hardware platform with an established temporal and spatial isolation. On-chip communication systems for such platforms must support different bandwidth and latency requirements of applications while preserving time predictability. In this paper, our concern is a time-predictable on-chip network architecture for targeting applications in mixed-criticality aerospace systems. The proposed architecture introduces a mixed, priority-based and time-division-multiplexed arbitration scheme to accommodate different bandwidth and latency in the same network while preserving worst-case time predictability for end-to-end communication without packet loss. Furthermore, as isolation of erroneous transmission by a faulty application is a key aspect of contingency management, the communication system should support isolation mechanisms to prevent interference. For this reason, a sampling port and isolated sampling buffer-based approach is proposed with a transmission authorisation control mechanism, guaranteeing spatial and temporal isolation between communicating systems.

A Two-Phase Multiobjective Local Search for the Device Allocation in the Distributed Integrated Modular Avionics

In the distributed integrated modular avionics (DIMA), it is desirable to assign the DIMA devices to the installation locations of the aircraft for obtaining the optimal quality and cost, subject to the resource and safety constraints. Currently, the routine device assignments in DIMA are conducted manually or by experience, which becomes more and more difficult with the increasing number of devices. Especially, in the face of large-scale device assignment problems (DAPs), the manual allocation will become an almost impossible task. In this paper, a bi-objective safety-constraint device assignment model in DIMA is formulated with the integer encoding for better scalability. A two-phase multiobjective local search (2PMOLS) is proposed for addressing it. In the first phase of 2PMOLS, the fast convergence of the population toward the Pareto front (PF) is achieved by the weighted sum approach. In the second phase, Pareto local search is conducted on the solutions delivered in the first phase for the extension of the PF approximation. 2PMOLS is compared with three decomposition-based approaches and one domination-based approach on DAPs of different sizes in the experimental studies. The experimental results show that 2PMOLS outperforms all the compared algorithms, in terms of both the convergence and diversity. It has also been demonstrated that the solution obtained by 2PMOLS is better in terms of both objectives (mass and ship set costs), compared with the solution designed by the domain expert. The experimental results show that 2PMOLS performs increasingly better with the increase of the problem size, compared with other algorithms, which indicates it has better scalability.

Avionics system failure analysis and verification based on model checking

Integrated modular avionics (IMA) are universally considered to be safety-critical and software-intensive systems. IMA can effectively reduce research and development costs and improve efficiency by reducing weight and power consumption through comprehensive resource integration or high resource-sharing comparison. However, failures in IMA may have catastrophic consequences. Failure analysis and verification of this system have become increasingly challenging. Model checking is an efficient technique to verify whether all the state transition traces satisfy the safety requirements or safety properties; however, difficulties are associated with defining or analyzing appropriate safety requirements, including for potential hazards. Systems-Theoretic Process Analysis can be used to identify potential failure hazards in complex systems. In this paper, a technique integrating which Systems-theoretic Process Analysis and model checking is proposed to perform failure analysis and verification, which better identify potential failure, derive safety requirements, and find failure propagation paths. Finally, the validity of the method is verified in the case study. The results indicate the practicability and effectiveness of the proposed method.

Redundant Computing Resources Management of Integrated Modular Avionics

In article the structure and the control algorithm are considered by diverse redundancy of the computing system of the perspective integrated modular avionics. Computing resources of the integrated modular avionics system are generally represented by heterogeneous computing systems used for information processing as part of the onboard integrated computing environment. The basis of heterogeneous computing systems are processor nodes, redundancy of computing systems is that the number of processor nodes is greater than one. The task is to synthesize such a computer system in which the automatic control of redundant computational resources would be carried out by using the own capabilities of the processor nodes and without the use of additional hardware resources. It is considered that the redundant computer system performs meaningful calculations of the problem solved by several processor nodes in parallel. All meaningful calculations for any signs initially divided into relatively short stages, providing an opportunity to assess the effectiveness of the completion of each of them. The computational system redundancy management is based on the periodic calculation and comparison of the success indicators of the stage. Pairwise arbitration of processor nodes is carried out according to a hierarchical scheme by comparing the values of the success indicators of the stages of the same name. Subsequent reconfiguration of the computer system allocates passive and leading processor nodes in pairs at all levels of the hierarchical scheme. The failure of the passive processor node does not affect the execution of the main cycle. The failure of the host processor node does not cause interruptions in the output of the results of calculations, but destroys the structure of reserves, which is restored after arbitration in the next cycle. Failure of the lead CPU top node leads to the failure output in the current cycle, the computational process is restored along with the new hierarchy of the computing system in the next cycle. The proposed solution is aimed at parrying both hardware failures and software malfunction. The methodical example based on the computer system of the modern onboard equipment complex of the transports category aircraft is resulted.