Manuel Prieto

LEON2 cache characterization. A contribution to WCET determination

A study about cache performance in LEON2 spaceborne processor is presented. This study has been carried out in collaboration with EADS Astrium Toulouse and its purpose is to analyse the impact of the cache of LEON2 microprocessor in the WCET determination. In order to reach this objective, a cache characterization has been performed through a battery of low and high level test benches.

A year of operation of Melibea e-Callisto Solar Radio Telescope

The e-CALLISTO (Compound Astronomical Low-cost Low-frequency Instrument for Spectroscopy and Transportable Observatory) is a worldwide radio-spectrograph network with 24 hours a day solar radio burst monitoring. The e-CALLISTO network is led by the Swiss Federal Institute of Technology Zurich (ETHZ Zurich), which work up collaborations with local host institutions. In 2013 the University of Alcala joined the e-CALLISTO network with the installation of two Solar Radio Telescopes (SRT): the EA4RKU-SRT that was located at the University of Alcala from January 2013 till June 2013 and the Melibea-SRT that is located at Peralejos de las Truchas (Guadalajara) in operation from June 2013. The Spanish e-Callisto SRTs provide routine data to the network. We present examples of type III and type II radio-bursts observed by Melibea during its first year of operation and study their relation with soft X-ray flares observed by GOES and Coronal Mass Ejections (CMEs) and Solar Energetic Particle (SEP) events observed by space-borne instrumentation.

Improving the LEON Spacecraft Computer Processor for Real-Time Performance Analysis

M ODERN processors include architectural features such as pipelines, caches, and branch-prediction units that can result in significant performance improvements.However, these enhancing features introduce a high level of unpredictability and uncertainty into theworkload behavior. To obtain a better understanding of these techniques and to allow the development of architectural improvements, most of these processors include hardware support for nonintrusive monitoring of a variety of system events. Commonly referred to as hardware performance counters, this capability is very useful to both applications developers and computer architects. Through these counters we can collect information about program behavior, analyze performance, and identify the causes of possible bottlenecks. These counters are an integral part of the performancemonitoring unit (PMU). Commonly, the performance counters provide information about the number of instructions executed, dataand instruction-cache hit rates, the number of branchmispredictions, and the number of interrupts handled. Usually, methods for implementing code coverage analysis tools are based on program instrumentation. This approach presents the disadvantage of introducing an elevated overhead, due to the insertion and execution of instrumentation code, and these schemes are typically not portable to many software environments. PMUs attempt to lower this overhead by leveraging the number of performance counters and events that can be managed [1–4]. The availability of PMUs in processors for space applications is usually related to their origin. On one hand, these processors can be adapted versions of commercial general-purpose microprocessors. In this case, their technologies are modified to be radiation-tolerant. However, their architectures are notmodified, because it can produce a great increment of the price or reliability loss. Therefore, these processors will have a PMU if it is present in their commercial version, such as the processors based on PowerPC architecture (RAD6000 and RAD750 fromBAE systems or hardware-embedded processors in Xilinx devices). On the other hand, PMUs are not commonly available in space-borne microprocessors such as HX1750, MAS281, and the LEON architecture; this can be mainly for two reasons. First is the fact that it involves validation cost and device resource consumption. Second, only specific real-time applications need a PMU. LEONarchitecture is widely employed for spacecraft applications with tight real-time execution-time guarantees and is being used on missions such as BepiColombo. This limitation can be solved, due to the availability of itsVeryHighSpeed Integrated Circuit Hardware Description Language (VHDL) source code. New performance counters can be included at a very small hardware cost, due to the low number of required resources. Moreover, the processor performance is not degraded, and no critical timing paths are included in the system, due to the nonintrusive behavior of the new feature. In real-time systems, due to the criticality of the tasks that are executed and the need to ensure that the system will always perform its required functionality within the specified deadlines, it is mandatory to have a precise knowledge of the system behavior. For instance, obtaining accurate information about the longest time that a portion of a program or software can take to run, termed the worstcase execution time (WCET) [5,6], is a key issue to ensure that time constraints are met and that real-time systems operate correctly. WCET determination becomes crucial in critical applications in Received 6 April 2010; revision received 23 March 2011; accepted for publication 27 March 2011. Copyright

Development of the MicroSat Programme at INTA

This paper presents the INTAµSAT programme initiative and its development status. With a mass ranging from 80 to 150 Kg and compatible with the Ariane-5 ASAP, the Phase-A one year study was initiated in Oct. 05. At this moment we are running the Phase-B started in Nov. 06 that will finish with a PDR in Dec. 07. The first INTAµSAT-1 will be a very agile Earth observation mission using CMGs, with a launch tentative date by the beginning of 2010. This enlarged µSAT class is a further step after the NANOSAT programme success cite ch04:bib01 with a launch onboard Ariane-5 V-165 in Dec. 04 (Nanosat-01 still working OK in orbit), and the next Nanosat-1B planned to be launched most probably in a DNEPR by the middle of 2008. It will be followed by Nanosat-2, an evolved 15–40 Kg satellite with improved service module resources and a separated payload module design, set for launch by 2011.

AN AI ELECTRICAL GROUND SUPPORT EQUIPMENT FOR CONTROLLING AND TESTING A SPACE INSTRUMENT

A versatile and modular electrical ground support equipment (EGSE) system has been developed using artificial intelligence (AI) techniques to control and test the PESCA instrument and the communication process of the satellite without any human supervision. The PESCA instrument has been designed and built with the purpose of studying solar energetic particles and the anomalous cosmic rays. It will be part of the Russian FOTON satellite payload that is scheduled to be launched in December 2007. The tool allows complete and autonomous control, verification, and validation of the PESCA instrument, although its modularity makes it extensible to other onboard instruments.

Control and acquisition system of a space instrument for cosmic ray measurement

Abstract The PESCA Instrument Control and Acquisition System (PICAS) design, building and tests are presented. The purpose of the PESCA instrument is the study of the Solar Energetic Particles and the Anomalous Cosmic Rays. It is, therefore, a satellite on-board instrument. The PICAS is basically a computer, composed of a microprocessor with a memory block and a set of interfaces for the communication with the rest of the instrument and the satellite. The PICAS manages all the comunication processes with the satellite, that comprises the order reception from the ground station, and the telemetry sending, that includes scientific data and housekeeping data. By means of telecommands, the PICAS is completely controllable from the ground. The PICAS is also a reliable data acquisition system that guarantees the correct reception of the Cosmic Rays data collected in the ground.

Thaw depth spatial and temporal variability at the Limnopolar Lake CALM-S site, Byers Peninsula, Livingston Island, Antarctica

A new Circumpolar Active Layer Monitoring (CALM) site was established in 2009 at the Limnopolar Lake watershed in Byers Peninsula, Livingston Island, Antarctica, to provide a node in the western Antarctic Peninsula, one of the regions that recorded the highest air temperature increase in the planet during the last decades. The first detailed analysis of the temporal and spatial evolution of the thaw depth at the Limnopolar Lake CALM-S site is presented here, after eight years of monitoring. The average values range between 48 and 29cm, decreasing at a ratio of 16cm/decade. The annual thaw depth observations in the 100×100 m CALM grid are variable (Variability Index of 34 to 51%), although both the Variance Coefficient and the Climate Matrix Analysis Residual point to the internal consistency of the data. Those differences could be explained then by the terrain complexity and node-specific variability due to the ground properties. The interannual variability was about 60% during 2009-2012, increasing to 124% due to the presence of snow in 2013, 2015 and 2016. The snow has been proposed here as one of the most important factors controlling the spatial variability of ground thaw depth, since its values correlate with the snow thickness but also with the ground surface temperature and unconfined compression resistance, as measured in 2010. The topography explains the thaw depth spatial distribution pattern, being related to snowmelt water and its accumulation in low-elevation areas (downslope-flow). Patterned grounds and other surface features correlate well with high thaw depth patterns as well. The edaphic factor (E=0.05842m2/°C·day; R2=0.63) is in agreement with other permafrost environments, since frozen index (F>0.67) and MAAT (<-2°C) denote a continuous permafrost existence in the area. All these characteristics provided the basis for further comparative analyses between others nearby CALM sites.

SIDRA instrument for measurements of particle fluxes at satellite altitudes. Laboratory prototype

The design concept and first set of results are presented for electronic modules of a laboratory prototype of the small-size satellite instrument SIDRA intended for measurements of charged particle fluxes in outer space. The working prototype consists of a detector assembly based on high-purity silicon and fast scintillation detectors, modules of analogue and digital processing, and a secondary power supply module. The first results are discussed of a Monte-Carlo simulation of the instrument with the use of the GEANT4 toolkit and of measurements of the main parameters of charge-sensitive pre-amplifiers, shapers, and peak detectors. Results of calibration measurements with the use of radioactive sources and beams of accelerated charged particles are presented.

Breadboard model of the SIDRA instrument designed for the measurement of charged particle fluxes in space

This report delves into the concept of the SIDRA instrument designed for the measurement of energetic fluxes of charged particles in space. It also presents the preliminary laboratory tests results of the breadboard model electronic units. The SIDRA instrument consists of a detector head made of high purity silicon and high performance scintillation detectors, analog and digital signal processing units, and it also includes a secondary power supply module. Preliminary results of Monte Carlo instrument simulation using the CERN GEANT4 tool are presented and the measured key specifications of charge-to-voltage converters, shapers and peak detectors are discussed. Finally, the performance of the digital processing unit with its software and the parameters of the instrument breadboard model, in particular mass, dimensions and power consumption are also presented.

INTAμSat-1 First Earth Observation Mission

This chapter is a description of the INTAμSat-1 first Earth observation mission objectives and its development status. With a mass around 100 kg and a 60 × 60 × 90 cm size compatible as an auxiliary payload for VEGA, Soyuz-ST and Dnepr, the project is running now the Phase-C and will be ready for launch by the middle of 2011. This new INTA small satellite programme initiated in October 2005, belongs to the well known μSAT class (up to 150 kg) as a further step after the Nanosat programme success: first Nanosat-1 with a 19 kg mass and still working OK in orbit that was launched by Ariane-5 in December 2004; and Nanosat-1B with 23.5 kg set for launch in a DNEPR by July 2009 from Baikonur. In fact both programmes will be running in parallel at INTA with next Nanosat-2 tentatively set for launch by 2013. It will be an evolved 20–50 kg s/c with improved service module resources and a separated payload modular design. After the preliminary progress on the different platform subsystems design, it was decided by the middle of Phase-B in October 2007 that the first μSAT demonstration flight will be devoted to an experimental Earth observation payload with several instruments, together with some technological experiments. Both the Service Module (SVM) and Payload Module (PLM) are fully developed at INTA, with contributions from several Universities and few small Spanish companies. INTAμSat-1 PLM will carry the following instruments: (1) CINCLUS, a 30 m GSD pushbroom TDI camera with a wide swath, that will try to collect information on the water quality over more that 150 reservoirs spread out over the Spanish territory, with a repetition cycle of 9 days; (2) MS-WAC, a 10 m GSD wide swath MS camera with 4–5 channels that will provide full coverage of Spain also in 9 days; PAU, a combined reflectometer–radiometer that using GPS reflected signals will try to measure the sea surface height variations and salinity. All this PL data will be transmitted down to Maspalomas ground receiving station in X-band at 40–80 Mbps, while the Control Centre (CC) will use the same Nanosat CC facilities for S-band TT&C available at INTA headquarters in Torrejon de Ardoz, Madrid.