Xavier Olive

TAS · Avant projet

Free space optical communications are becoming a mature technology to cope with the needs of high data rate payloads for future low‐earth orbiting observation satellites. However, they are strongly impacted by clouds. In this paper, we aim to find a network of optical ground stations maximizing the percentage of data acquired by a low‐earth orbitin...

Free-space optical communications are becoming a mature technology, but unlike current radio-frequency technologies, they are strongly impacted by clouds. In this paper, we aim to find a network of optical ground stations maximizing the amount of data that can be sent from a low-earth orbiting satellite to the Earth during its missions, taking into...

Editor in chief: C. Ferrari; Editors: M. Alves, S. Bosse, S. Corbel, A. Ferrari, K. Ferri\`ere, S. Gauffre, E. Josselin, G. Lagache, S. Lambert, G. Marquette, J.-M. Martin, M.-A. Miville-Desch\^enes, L. Montier, B. Semelin, G. Theureau, S. Vergani, N. Vilmer, P. Zarka; Original file with high resolution figures at SKA-France link: https://ska-franc...

The "Square Kilometre Array" (SKA) is a large international radio telescope project characterised, as suggested by its name, by a total collecting area of approximately one square kilometre, and consisting of several interferometric arrays to observe at metric and centimetric wavelengths. The deployment of the SKA will take place in two sites, in S...

Establishing and managing a “good” set of requirements is one of the critical success factors for any space system project, and for the development of any complex product in general. The NextGenRE project sponsored by the European Space Agency has developed an innovative approach featuring the use of semantic wiki technology to enable users to spec...

The paper deals with the application of a formalized fault diagnosis strategy for multiple faults occurring in an autonomous spatial vehicle. The research work draws expertise from a collaboration between the European Space Agency, the “Laboratoire de lʼIntegration du Materiau au Systeme” and the Thales Alenia Space industry. The goal is to demonst...

In this paper, we present the problem of planning the acquisitions performed by a constellation of radar satel-lites in order to fulfil as well as possible an ocean global surveillance mission. Then, we describe the local search algorithm, inspired by large neighborhood search tech-niques and knapsack heuristics, that has been specifically designed...

This paper considers the problem of allocation of down-link windows for a constellation of satellites whose mis-sion is to perform a regular surveillance of ship move-ments over all the oceans. This surveillance is realized using both radar acquisitions of specific areas and ac-quisition flows continuously collected over the whole or-bits. These ac...

FDI(R) for satellites: How to deal with high availability and robustness in the space domain? The European leader for satellite systems and at the forefront of orbital infrastructures, Thales Alenia Space, is a joint venture between Thales (67%) and Finmeccanica (33%) and forms with Telespazio a Space Alliance. Thales Alenia Space is a worldwide re...

Given a partially observable dynamic system and a diagnoser observing its evolution over time, diagnosability analysis for-mally verifies (at design time) if the diagnosis system will be able to infer (at runtime) the required information on the hid-den part of the dynamic state. Diagnosability directly depends on the availability of observations,...

The need for an integrated system-software co-engineering framework to support the design of modern space systems is pressing. The current tools and formalisms tend to be tailored to specific analysis techniques and are not amenable for the full spectrum of required system aspects such as safety, dependability and performability. Additionally, they...

European leader for satellite systems and at the forefront of orbital infrastructures, Thales Alenia Space is a joint venture between Thales (67%) and Finmeccanica (33%) and forms with Telespazio a Space Alliance. Thales Alenia Space is a worldwide reference in telecoms, radar and optical Earth observation, defense and security, navigation and scie...

This paper addresses the design of model-based fault diagnosis schemes to detect and isolate faults occurring in the orbiter thrusters of the Mars Sample Return (MSR) mission. The proposed fault diagnosis method is based on a H(0) filter with robust poles assignment to detect quickly any kind of thruster faults and a cross-correlation test to isola...

European leader for satellite systems and at the forefront of orbital infrastructures, Thales Alenia Space is a joint venture between Thales (67%) and Finmeccanica (33%) and forms with Telespazio a Space Alliance. Thales Alenia Space is a worldwide reference in telecoms, radar and optical Earth observation, defense and security, navigation and scie...

With the increase of critical data exchanges in embedded real-time systems, the computation of tight upper bounds on network traversal times is becoming a crucial industrial need especially in safety critical systems. To address this need, the French project PEGASE grouping academics and industrial partners from the aerospace field has been underta...

This paper presents a formalized diagnosis technique for the isolation of multiple faults occurring in the orbiter's measurement unit of the Mars Sample Return mission. The Mars Sample Return (MSR) mission is a flagship mission undertaken jointly by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The go...

This paper addresses the diagnosis of hybrid systems switching between operating modes that undergo saturation behaviors. It proposes to generate non-linear parameterized ARRs, and to account for all regions of linear behavior, i.e. nominal, faulty and saturation regions, with automata representing the transitions between them at the level of each...

The issue of residual generation using structural analysis has been studied by several authors. Structural analysis does not permit to generate the analytical expressions of residuals since the model of the system is abstracted by its structure. However, it determines the set of constraints from which residuals can be generated and it provides the...

Thales Alenia Space is developing a new generation of satellites dedicated to flexible and autonomous Space missions. It relies on a hierarchical component based architecture. Hierarchical layers are devoted to manage on one hand, different kind of knowledge from abstract (goal of the mission) to real (units, equipments), and on the other hand, dif...

On-line diagnosis must accommodate the existing sensoring capabilities of a system, which often results in limited diagnosability. However, in the context of hybrid systems, although faults may not be always discriminable, there are generally operating modes of the system in which they are. Active diagnosis relies on applying specific inputs to the...

Thales Alenia Space is developing a new generation of satellites dedicated to flexible and autonomous Space missions. It relies on a hierarchical component based architecture. Hierarchical layers are devoted to manage on one hand, different kind of knowledge from abstract (goal of the mission) to real (units, equipments), and on the other hand, dif...

This paper gives an overview of the Gene-Auto ITEA European project, which aims at building a qualified C code generator from mathematical models under Matlab-Simulink and Scilab-Scicos. The project is driven by major European industry partners, active in the real-time embedded systems domains. The Gene- Auto code generator will significantly impro...

On-board file system allows to control and operate a spacecraft in new way offering more possibilities. It should permit to provide to the Operator a more abstract data view of the spacecraft, letting them focus on the functional part of their work and not on the exchange mechanism between Ground and Board. Files are usually used in the recent spac...

In this paper we propose a hybrid system modeling framework aimed at analyzing diagnosability. In this framework, the hybrid system is seen as the composition of an underlying discrete event and an underlying continuous systems. Diagnosability of these two underlying systems are fully analyzed and new results are provided for the underlying continu...

Space missions may benefit from a more advanced autonomy level in different ways: reduction of ground operations, reduction of the occurrence of service interruptions or improvement of the reactivity of the system. Depending on the mission requirements, new functions need to be supplied on-board the spacecraft, such as mission planning or failure d...

This paper deals with the problem of diagnosing systems that exhibit both continuous and discrete event dynamics. The proposed approach combines techniques from both continuous and discrete event diagnosis fields. On the on hand, an extension of the parity space approach is used to associate signatures to every operational mode of the system. On th...

The trend in terms of telemetry volume is to generate on-board more and more data due to the fact that ground operators like to have a full observability of spacecrafts embedding functionalities which are more and more complex to control. In addition the budget for the TM bandwidth is often poor and restricted wrt the mission. Transmitting less vol...

This first technical session is further developing the technological dimensions of technology transfer, with three illustrations of successful and representative industrial applications. It covers the cases of embedded autonomy in spacecraft applications, advanced avionics solutions for satellite communication and component hybridization for naviga...

This first technical session is further developing the technological dimensions of technology transfer, with three illustrations of successful and representative industrial applications. It covers the cases of embedded autonomy in spacecraft applications, advanced avionics solutions for satellite communication and component hybridization for naviga...

It is commonly accepted that the requirements for maintenance and diagnosis should be considered at the earliest stages of design. For this reason, methods for analyzing the diagnosability of a system and determining which sensors are needed to achieve the desired degree of diagnosability are highly valued. This paper clarifies the different diagno...

Cet article propose 2 m´ethodes qui permettent de générer des arbres de diagnostic presque optimaux de manière performante en terme de temps de calcul et en limitant la perte d’optimalit´e. Ce travail est basé sur une approche à base de modèles (AGENDA) pour la génération d’arbres de diagnostic optimaux en utilisant un algorithme AO*. Les entrées d...

This paper deals with a model-based Automatic GENeration of DiAgnosis trees method (AGENDA) using the AO* algorithm. The inputs of this algorithm are the anticipated faults which may occur on the system to diagnose with their respective occurrence probability, the anticipated tests that can be performed and the cross-table which assigns to each (fa...

In the automotive field, the use of an ECU (Electronic Control Unit) to control several functions (such as engine injection or ABS) increases. To diagnose such systems, diagnosis trees are built. These trees allow the garage mechanics to find the faulty component(s) by performing a set of tests (measurements) which has the lowest global cost as pos...

This paper presents two methods which allow us to generate near optimal diagnosis trees in an efficient way while reducing the optimality loss. These methods use a model-based Automatic GENeration of DiAgno- sis trees method (AGENDA) using the AO* algorithm. The inputs of this algorithm are the faults which may occur on the system to diagnose with...

This paper presents a model based methodology that relies on the sound basis of the most recent and widespread applicable system engineering standards and model based practices, The methodology has been defined to support domain specific space system engineering standards and practices and assessed through the application on industrial case studies...