Airborne Software Research Articles

Research on schedulability analysis algorithm of airborne multi partition system

Partition operating system conforming to ARINC653 is widely used in airborne to support application software integration. Under the two-level scheduling model for partition operating system, the demanding real-time requirements of airborne software are usually difficult to obtain effective deterministic guarantee, so it is very important to analyze the schedulability of the system. Judging whether the scheduling table can meet the real-time requirements of the process in the partition through the schedulability analysis algorithm is an effective means to ensure that all processes in the system complete the computing task within the specified time. Based on the method of operations research and the introduction of virtual process, a schedulability analysis algorithm for multi partition system is designed, and the numerical verification is carried out. The verification results show that the algorithm can accurately judge whether the scheduling table matches the process time attribute, give the qualitative analysis conclusion of whether the system can be scheduled, help the system integrator to verify the rationality of the scheduling table before the actual operation of the system, and reduce the risk of test and flight test.

A Flexible Code Review Framework for Combining Defect Detection and Review Comments

Defects and errors in code are different in that they are not detected by editors or compilers but pose a potential risk to software operation. For safety-critical software such as airborne software, the code review process is necessary to ensure the proper operation of software applications and even an aircraft. The traditional manual review method can no longer meet the current needs with the dramatic increase in code sizes and variety. To this end, we propose Deep Reviewer, a general and flexible code review framework that automatically detects code defects and correlates the review comments of the defects. The framework first preprocesses the data using several methods, including the proposed D2U flow. Then, features are extracted and matched by the detector, which contains a pair of twin LSTM models, one for code defect type detection and the other for review comment retrieval. Finally, the review comment output function is implemented based on the masks generated by the code defect types. The method is validated using a large public dataset, SARD. For the binary-classification task, the test results of the proposed are 98.68% and 98.67% in terms of precision and F1 score, respectively. For the multi-classification task, the proposed framework shows a significant advantage over other methods.

The study of Simulation Intelligent Analysis System of UAV Control On the basis of Computer Big Data Technology

With the advent of the era of computer big data, the application of big data is increasing. Computer big data technology is suitable for the analysis of UAV simulation intelligent system, which can clarify its practicability. After the intelligent analysis system is put into use, the accuracy of UAV control is improved. The UAV flight control system is the core part of UAV, and the performance of UAV depends on the design of its flight control system to a great degree. In this paper, the intelligent analysis system of UAV control simulation is studied. The accuracy of massive data set algorithm with adaptive selection and adjustment strategy and the complex causal relationship between data in the intelligent analysis system of UAV control simulation under computer big data technology are studied. The research results show that the global optimization of the whole process can be ensured by combining the structural characteristics and algorithms of data-to-data association algorithm, and the data is more than 58.96%. Therefore, the intelligent analysis system of airborne software simulation, which provides guarantee for the research and development of UAV control through testing, has a certain market application space and prospect.

Study on Technical Focuses and Sampling Coverage Strategy of Airborne Software Reviews

Study on Technical Focuses and Sampling Coverage Strategy of Airborne Software Reviews

On-the-Fly Repairing of Atomicity Violations in ARINC 653 Software

Airborne health management systems prevent functional failure caused by errors or faults in airborne software. The on-the-fly repairing of atomicity violations in ARINC 653 concurrent software is critical for guaranteeing the correctness of software execution. This paper introduces RAV (Repairing Atomicity Violation), which efficiently treats atomicity violations. RAV diagnoses an error on the fly by utilizing the training results of software and treats to control access to the shared variable of the thread where the error has occurred. The evaluation of RAV measured the time overhead by applying methods found in previous works and RAV to five synthesis programs containing an atomicity violation.

Study on Technical Focuses and Sampling Coverage Strategy of Airborne Software Reviews

Airborne software is invisible and intangible, it can have a significant impact on the safety of the aircraft. However, it cannot be exhaustively tested, and can only be assured through a structured, process, activity, and objective-based approach. This paper studied the similarities and differences of software review policies of the four selected National Airworthiness Authorities (NAAs) by using a comparative approach and analysed the general certification basis of specific regulation clauses from the International Civil Aviation Organization Conventions to each contracting States’ regulations by a traceability method. Then analyzed the development processes and objectives applicable to different software levels based on RTCA/DO-178C. Identified 82 technical focus points based on each airborne software development subprocess, then created a Process Technology Coverage matrix to demonstrate the technical focuses of each process. Developed an objective-oriented top-down and bottom-up sampling strategy for the 4 software Stage of Involvement reviews by taking into account the frequency and depth of involvement. Finally, created the Technology Objective Coverage matrix, which can support the reviewers to perform the efficient risk-based SOI reviews by considering the identified technical points, thus to ensure the safety of the aircraft from the software assurance perspective.

Architectural Process for Flight Control Software of Unmanned Aerial Vehicle with Module-Level Portability

To apply UAVs (Unmanned Aerial Vehicle) into different fields, including research and industry, and expand it quickly, reliable but modular software is required. The existing flight control software (FCS) of the UAV consists of various types of modules categorized into different layers, and it is responsible for coordinating, monitoring, and controlling the vehicle during its flight. This paper proposes mpFCS, a structure of UAV flight control software, which provides portability to its modules and is easy to expand. The mpFCS consists of four segments and several modules within the segments. mpFCS provides portability for each module within the segment. Existing software does not provide portability for its modules because of the tight coupling resulting from its different and private interfaces. The mpFCS uses interfaces of the standard airborne software architecture to transfer data between its modules. Moreover, the structure provides portability for its modules to run in the standard airborne software environment. In order to verify the mpFCS, we tested the mpFCS with the conformance test suite of the airborne software that provides the testing environment for the interfaces and modules of the software. The mpFCS passed the test. Test results show that all modules of the mpFCS are portable. Additionally, portable modules can be interoperable with other software, and the structure is expandable with new modules that use standard airborne software interfaces.

The Design Assurance Method of Reused Airborne Software

Reusing software data from different sources and different reuse methods will affect the full compliance of civil aircraft airborne software. To achieve cost and risk reduction in reused software project, firstly classification of reused airborne software is confirmed and assessment elements are recognized; secondly the assessment framework of software reuse is established and assessment activities and sequences are specified; lastly the reused software design assurance requirements are given from the perspective of certification. This study can provide support for stakeholders of reused software certification to recognize and assess reused software and generate certification strategy in the early stage of project.

Reuse Strategy for the Previously Qualified Software Tool of Airborne Software

Although the software tool qualification should be based on the specific airborne software, it is impractical to develop the software tool for one software program. Most software tools, especially for the COTS tools, would be reused in multiple software programs. This paper capture and analyzes the requirements for the previously qualified software tool in the related standards and certification guidance, and proposes a strategy and framework for the reusing the previously qualified software tool to meet the requirements of different standards and certification authority.

Verification of Air Data Computer Software using Formal Methods

With the rapid development of airborne system and software, the requirement of software’s robustness, adaptability and reliability improves continually. Failure of software function may cause severe property loss and personnel casualties. Formal methods are mathematically based techniques for the specification, development, and verification of software aspects of digital systems that have obvious advantages in improving safety and reliability of airborne software. This paper takes Air Data Computer software as an example for formal verification in the whole software development process including requirements process, design process, coding process and integration process to demonstrate a set of formal methods application in the airborne software verification process.

Research on Means of Compliance for Airborne COTS Software

The cost of airborne software development is very high, and the functions implemented by airborne software are becoming more and more complex. Using the COTS software has become a trend in case of saving cost. The COTS software brings conveniency, meanwhile raise problems when showing compliance to airworthiness requirements. This paper researches the design assurance method of COTS software, summaries the certification risks and propose a feasibility analysis of using COTS software, thus providing reference for airborne systems designs.

Airborne Software Change Control Process and Strategies of Civil Aircraft

In the modern civil aircraft, the number and complexity of airborne software are increasing rapidly. The software may change at any stage of the development process and the change process should be under control. This article analyzes the basic unit of software change control and the configuration identification used for airborne software, then introduces a process and strategies of software change control for civil aircraft.

Tool Qualification Requirements Comparison and Analyses Between RTCA/DO-178B and RTCA/DO-178C+DO-330

The RTCA/DO-330 “Software Tool Qualification Consideration” is released after the RTCA/DO-178B was widely used for tool qualification in the latest 20 years. In the RTCA/DO-178C collection, the RTCA/DO-330 is used together with RTCA/DO-178C to define the tool qualification requirements for airborne software development. This paper compares and analyses the different requirements in RTCA/DO-178B and RTCA/DO-178C+DO-330 to provide an indication of what are the new requirements and what has not been changed. For those unfamiliar with the tool qualification requirements in RTCA/DO-178C and RTCA/DO-330, this paper serves to provide an entry point to this new certification guidance.

Airborne Software Data Coupling and Control Coupling Analysis

As a part of software structural coverage, the data coupling and control coupling analysis help to evaluate the implementation of requirements and the code quality to some extent. This paper researches the data and control coupling definitions, analysis methods and the differences of requirements between DO-178B and DO-178C, thus providing reference for airborne software verification.

A Safety Analysis Method of Airborne Software Based on ARP4761

Most of the functions of civil aircraft are achieved through software at present. Therefore, the safety of airborne software has become an important part of safety analysis. However, to achieve complex functions, the onboard software becomes very complicated, and it is usually difficult to guarantee safety. ARP4761(Guidelines and Methods for Conducting the Safety Assessment Process on Civil Airborne Systems and Equipment) is an important safety assessment guideline for civil aircraft, but it believes that software development can satisfy safety as long as the software development process complies with the software development standards, instead of incorporating the software into the safety analysis process. To improve airborne software safety, this paper proposes a safety analysis method based on the ARP4761 process which is tailored to adapt to the software. In the software requirements and design, the method uses FHA(Functional Hazard Assessment) to analyze the hazards of the software and define the hazard levels, then use FTA(Fault Tree Analysis) to build a software fault tree, and carry out CCA(Common Cause Analysis) analysis based on the fault tree; after the software development is completed, the method uses FMEA(Failure Modes and Effects Analysis) and FMES(Failure Modes and Effects Summary) to summarize the failures of the software and return these failures to the fault tree to determine whether the software can meet the defined requirements. At the end of the article, an anti-icing software is used as an example to explain the process and effectiveness of the method.

항공기 소프트웨어의 건전성 관리를 위해서 순서 위배 오류를 자율 수리하는 효율적인 시스템

항공기 소프트웨어의 건전성 관리시스템은 수행 중에 발생하는 오류를 수리하여 안전성을 제공하고 유지보수 비용을 절감한다. 순서 위배 오류는 개발 단계에서 모두 제거하는 것이 어렵기 때문에 운용 단계에서 자율적으로 수리할 수 있어야 한다. 순서 위배를 자율 수리하기 위한 기존 연구는 각 접근사건의 수행 직전에 접근사건 순서를 비교하여 오류를 진단하기 때문에 접근사건 수에 비례하는 시간 오버헤드를 발생시킨다. 본 논문은 접근사건을 포함하는 함수의 올바른 순서 정보로 오류를 진단하고 해당 함수를 지연시켜 조치하는 기법인 ORS를 제시한다. ORS를 평가하기 위해, 순서 위배 오류를 포함하는 5가지의 합성 프로그램에 기존 연구와 ORS를 적용하여 시간 오버헤드를 측정하였다. 그 결과, 접근 횟수가 약 60번 이상일 때 기존 연구보다 효율적임을 확인하였다.

A Model-Based Approach to Optimizing Partition Scheduling of Integrated Modular Avionics Systems

The architecture of Integrated Modular Avionics (IMA) provides airborne software with a robust temporal partitioning mechanism, which achieves the reliable fault containment between avionics applications. However, the partition scheduling of an IMA system is a complex nonlinear non-convex optimization problem, making it difficult to solve the optimal temporal allocation for partitions using traditional analytical methods. This paper presents a model-based approach to optimizing the partition scheduling of IMA systems, whose temporal behavior is modeled as a network of timed automata. Given a system model, the optimizer employs a parallel genetic algorithm to search for the optimal partition resource parameters with respect to minimum processor occupancy. For each promising parameter combination, the schedulability constraints and processor occupancy of the system are precisely evaluated by Classical and Statistical Model Checking (i.e., CMC and SMC), respectively. We also apply SMC hypothesis testing to the fast falsification of non-schedulable solutions, thereby speeding up the schedulability verification based on CMC. Two case studies demonstrate that our proposed approach outperforms classical analytical methods on the processor occupancy of typical IMA systems.

Formal Analysis and Verification of Airborne Software Based on DO-333

With rapid technological advances in airborne control systems, it has become imperative to ensure the reliability, robustness, and adaptability of airborne software since failure of these software could result in catastrophic loss of property and life. DO-333 is a supplement to the DO-178C standard, which is dedicated to guiding the application of formal methods in the review and analysis of airborne software development processes. However, DO-333 lacks theoretical guidance on how to choose appropriate formal methods and tools to achieve verification objectives at each stage of the verification process, thereby limiting their practical application. This paper is intended to illustrate the formal methods and tools available in the verification process to lay down a general guide for the formal development and verification of airborne software. We utilized the Air Data Computer (ADC) software as the research object and applied different formal methods to verify software lifecycle artifacts. This example explains how to apply formal methods in practical applications and proves the effectiveness of formal methods in the verification of airborne software.

A Framework for Evaluating the Standards for the Production of Airborne and Ground Traffic Management Software

The development of Airborne and Ground systems is framed by specific regulations, usually expressed as standards. A disadvantage of those standards is the inherent complexity for its application and the verification of compliance given the high number of requirements to be checked in many different situations of the application and which are highly dependent on the applicable level of criticality. When the development of this type of system requires the incorporation of new personnel without enough knowledge about the standards, risks of mistakes in their application grow exponentially. The objective of this work is to develop an Expert System (ES) that helps to evaluate the application of the standards DO-178C and DO-278A throughout the project life cycle, at the same time it serves to facilitate both its use and the learning of its application to a wide group of professionals. The proposed underlying method for the ES will allow evaluating the set of development processes to check coverage of the standards DO-178C and DO-278A without depending on a specific life cycle model. The method involves a model of the set of processes, so they can be evaluated by the ES. Additionally, the ES will require a minimum configuration to evaluate the development of systems based on these two standards. The main result is a new generic Expert System based on rules capable of being adapted to different environment of evaluation, whichh minor configuration operations thus allowing that a Generic ES can act as a Specific ES for each situation. This configurable ES has been customized to evaluate the software life cycle based on the standards under study.

Verifying the Safety of Aviation Software Based on Extended Colored Petri Net

At present, various functions of aircraft have become more and more dependent on airborne software system, and the structure of modern airborne software is extremely complex. Engineers need to eliminate the situation in which the safety performance of the entirety reduces caused by mutual influence among components. This paper presents a comprehensive method with high efficiency for safety verification of airborne software system, in order to ensure the system meet safety requirement of airworthiness standard at the design stage. Safety Verification Colored Petri Net (SVCPN) for software safety verification is firstly proposed, and then the mapping transformation rules from Block Definition Diagram (BDD) of System Modeling Language (SysML) to SVCPN are proposed to achieve the accurately formal description of software system. Traversing all delivery paths of safety level transfer based on the Reachable Tree Diagram, to detect the components that do not meet the safety requirement of airworthiness standard. Based on the disambiguation algorithm, the fundamental components that cause safety problem are found out through the establishment of antinet to achieve the safety level reassign, ensuring the safety performance of the whole system. Finally, the case study and the comparison and analysis are applied to show the feasibility and superiority of our method.