OpenCL-Accelerated Simplified General Perturbations 4 Algorithm

The number of space objects such as satellites, spacecraft, and debris are increasing significantly, and so is the need for tracking them for security and collision avoidance purposes. In this context, as parallelism is becoming a new paradigm, the need of implementing high performance propagators remain unmet. For this, we implemented Simplified General Perturbations No. 4 (SGP4), a popular analytical orbital propagator, in OpenCL. OpenCL is a rising high performance and heterogeneous computation paradigm aimed to take the best of the processing elements on a given platform, in a paral- lel fashion, regardless of the underlying architecture. Despite some considerations had to be taken, we prove that our develop- ment shows no significant calculation differences, while not only being hardware independent, but also boosting the performance notably by two orders of magnitude in several scenarios.Sociedad Argentina de Informática e Investigación Operativ

GLOrbit: A 3D satellite orbit propagator for network topology analysis

Traditional networking protocols were developed for earth-based networks characterized by highly static topologies. In this scenario, erratic link failures were the most demanding change a network configuration could face. In the other hand, mobile networking protocols copes with dynamic topologies but assumes unknown trajectories and high connectivity. Neither of these applies to satellite constellations network paradigmwhere their orbiting nature describes a time-varying but highly predictive topology. To study satellite constellations networks we propose GLOrbit; a tool capable of propagate space nodes in time, create a 3D visual environment, and record the topology in different formats for further analytical studies. For this we implemented SGP4 propagation algorithm, OpenGL graphic library, and DOT language among other libraries interacting in a C++ program. This allows to obtain precise outputs for network graph and physical analysis while gaining visual intuition on satellite networks topologies for different orbital configurations. We demonstrate the tool capabilities with a first work on three representative low earth orbit topologies analysis generated by GLOrbit. Lineal, transversal, and different altitude scenarios are studied concluding that the first evidence an important strength in inter-satellite links while the second on ground to space contacts.Fil: Fraire, Juan Andrés. Universidad Nacional de Córdoba; Argentina.Fil: Ferreyra, Pablo. Universidad Nacional de Córdoba; Argentina.Fil: Marques, Carlos. Universidad Nacional de Córdoba; Argentina.Ingeniería Eléctrica y Electrónic

OpenCL-Accelerated Simplified General Perturbations 4 Algorithm

The number of space objects such as satellites, spacecraft, and debris are increasing significantly, and so is the need for tracking them for security and collision avoidance purposes. In this context, as parallelism is becoming a new paradigm, the need of implementing high performance propagators remain unmet. For this, we implemented Simplified General Perturbations No. 4 (SGP4), a popular analytical orbital propagator, in OpenCL. OpenCL is a rising high performance and heterogeneous computation paradigm aimed to take the best of the processing elements on a given platform, in a paral- lel fashion, regardless of the underlying architecture. Despite some considerations had to be taken, we prove that our develop- ment shows no significant calculation differences, while not only being hardware independent, but also boosting the performance notably by two orders of magnitude in several scenarios.Sociedad Argentina de Informática e Investigación Operativ

OpenCL-Accelerated Simplified General Perturbations 4 Algorithm

The number of space objects such as satellites, spacecraft, and debris are increasing significantly, and so is the need for tracking them for security and collision avoidance purposes. In this context, as parallelism is becoming a new paradigm, the need of implementing high performance propagators remain unmet. For this, we implemented Simplified General Perturbations No. 4 (SGP4), a popular analytical orbital propagator, in OpenCL. OpenCL is a rising high performance and heterogeneous computation paradigm aimed to take the best of the processing elements on a given platform, in a paral- lel fashion, regardless of the underlying architecture. Despite some considerations had to be taken, we prove that our develop- ment shows no significant calculation differences, while not only being hardware independent, but also boosting the performance notably by two orders of magnitude in several scenarios.Sociedad Argentina de Informática e Investigación Operativ

Diseño de Plan de Contactos para Redes Satelitales Tolerantes a Disrupciones

Tesis (DCI)--FCEFN-UNC, 2015Define y trata el problema de diseño de plan de contactos como el proceso de configurar y elegir apropiadamente estas oportunidades de transferencia de información de antemano con el fin de gestionar la utilización del sistema de acuerdo a las características de sus recursos, y al mismo tiempo, optimizarlo bajo un criterio dado para mejorar el flujo de datos tanto de instrumentos científicos como de telemetría de la plataforma

Centralized and Decentralized Routing Solutions for Present and Future Space Information Networks

International audienceSpace Information Networks (SINs) are pushing the boundaries of networking into near-Earth orbit and beyond. Nevertheless, the harsh and costly space context forces most riskprone missions to be designed with minimal chance of failure. The careful consideration of routing protocols used to connect the fleet is by no means the exception. Although decentralized SIN routing schemes received most of the attention of the research community, centralized approaches are captivating the industry, as these come with tighter control and do enable troubleshooting of valuable space assets from a mission control center on ground. In this paper, we settle the matter by qualitatively and quantitatively comparing both SIN paradigms. We propose two novel centralized routing schemes, and evaluate their resulting performance against Contact Graph Routing (CGR), the decentralized state-of-the-art. In this evaluation, computational effort, memory utilization, and energy consumption are taken as figures of merit. The outcome provides compelling evidence that centralized routing schemes can safely, successfully and efficiently connect SINs with up to 10k daily contacts, while CGR can be better entrusted with larger-scale SIN deployments

Space-Terrestrial Integrated Internet of Things: Challenges and Opportunities

International audienceLarge geographical regions of our planet remain uncovered by terrestrial network connections. Sparse and dense constellations of near-Earth orbit satellites can bridge this gap by providing Internet of Things (IoT) connectivity on a worldwide scale in a flexible and cost-effective manner. This paper presents STEREO: a novel Space-Terrestrial Integrated IoT Architecture spanning direct-and indirect-to-satellite access from IoT assets on the surface. Framed on the identified requirements, we analyze NB-IoT and LoRa/LoRaWAN features to put these technologies forward as appealing candidates for future satellite IoT deployments. Finally, we list and discuss the key open research challenges to be addressed in order to achieve a successful space-terrestrial IoT integration

Uplink Transmission Probability Functions for LoRa-Based Direct-to-Satellite IoT: A Case Study

International audienceDirect-to-Satellite IoT allows devices on the Earth surface to directly reach Low-Earth Orbit (LEO) satellites passing over them. Although an appealing approach towards a truly global IoT vision, scalability issues as well as highly dynamic topologies ask for dedicated protocol adaptations supported by novel models. This paper contributes to this research by introducing estimators and a transmission probability function to dynamically control the contending set of devices on a framed slotted Aloha model compatible with the LoRaWAN specification. In particular, we discuss techniques that account for particularities in the dynamics of sparse DtS-IoT constellations. Simulation analyses of a realistic case study show that >86% of the theoretical throughput is achievable in practice

LR-FHSS : j'ai perdu l'entête

National audienceLR-FHSS (Long-Range Frequency Hopping Spread Spectrum) est une récente modulation conçue pour que des équipements fonctionnant sur piles puissent transmettre des données à des satellites à basse orbite. Pour décoder une trame, la passerelle située sur le satellite doit recevoir au moins une copie de l'entête, et une grande proportion des fragments du payload. Toutefois, les entêtes LR-FHSS, plus longs que les fragments, ont de grandes chances d'être perdus lorsque le nombre de transmissions concurrentes est élevé. Dans ce papier, nous proposons une heuristique pour récupérer de telles trames LR-FHSS qui sont reçues sans entête. Nous montrons par simulation que notre heuristique a un comportement proche de l'optimal, en comparant ses résultats à ceux obtenus via un modèle linéaire en nombre entiers. Nous montrons aussi que notre heuristique peut récupérer beaucoup de trames reçues sans entête, tout en générant peu de faux positifs

Recovering Headerless Frames in LR-FHSS

International audienceLong-Range Frequency Hopping Spread Spectrum (LR-FHSS) is a recent modulation designed for communications from low-power ground end-devices to Low-Earth Orbit (LEO) satellites. To decode a frame, an LR-FHSS gateway must receive at least one header replica and a large proportion of payload fragments. However, LR-FHSS headers will likely be lost when there are many concurrent transmissions. In this paper, we motivate the header loss problem with an analytical model, propose a linear programming model to extract headerless frames and design a cost-effective sliding window heuristic. Simulation results show that our approach exhibits near-optimal headerless detection and extraction results while ensuring a low computational cost. The proposed method is, therefore, suitable for future LR-FHSS gateways located onboard resource-constrained LEO satellites