The data fusion is usually done in an estimation filter, so commonly this method is referred to as inertial stellar or gyro stellar estimation. - 1 Li-ion battery 15 Ah BOL; PCDU (Power & Control Distribution Unit), - On-board computer (T805, 1 Gbit DRAM/EDAC, 8 Mbit Flash EEPROM) - Forest fires are another application of satellite data as shown in Figure 14. The first of these, AlSat-2A, will be integrated and tested in France at EADS Astrium, whereas the second one, AlSat-2B, will be integrated in Algeria within the CDS (Satellite Development Center) in Oran. In order to further improve the attitude accuracy, multi-sensor data fusion is the common approach. AlSat-2 is 3-axis stabilized. Un lanceur spatial algérien serait en cours de préparation finale et serait utilisé pour procéder à ce lancement Le … The objective is to provide medium resolution satellite imagery as well as expertise to identify locust breeding areas in Sahel & Saharan regions — based on ecological conditions analysis by identifying zones on space imagery, with high chlorophyll activities, favorable to locust breeding and development. 20). Le satellite algérien, baptisé Alcomsat-1, a été lancé par la fusée chinoise « Longue Marche-3» depuis cette base située dans le sud-ouest de la Chine. - Gyro-stellar attitude determination - Since 2003, there is a collaboration between ASAL and INVP (Institut National de la Protection des Vegetaux). Note: CNES signed partnership agreements with AAS (Alcatel Alenia Space) and EADS/Astrium SAS which permits them to use the Myriade bus design and products for their own applications/missions (defense, commercial market, etc.). The SST will not be dazzled any more, just in the case of the moon presence, but this case happens monthly for short durations and not in imaging mode. Alsat-1b a été lancé le 26 septembre 2016 par un lanceur PSLV-C35[7]. Ses images sont utilisées pour la gestion des catastrophes naturelles et la protection de l'environnement[6]. The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. These different transitions allow the satellite to keep the equipments safe (e.g. B3: 0.62-0.69 µm (red) Reaction wheel configuration: The aim of pyramid configuration is to improve the satellite momentum in order to be agile and to ensure a back and forward imaging and along and across track imaging too. The NIEU represents the core of the electrical architecture. 12). Les deux satellites sont basés sur une plate-forme Myriade du Centre national d'études spatiales (CNES) et placé sur une orbite héliosynchrone polaire. Several attitude sensors have been developed with star trackers (SST) being the most accurate ones for three-dimensional orientation measurements. Il a été placé en orbite par un lanceur Cosmos-3M de la base russe de Plesetsk, le 28 novembre 2002. Le satellite algérien d’observation de la terre à haute résolution ALSAT-2A : Déjà 5 années de vie en orbite. Caractéristiques techniques (Alsat-2A, Alsat-2B), Site officiel de l'Agence spatiale algérienne, https://fr.wikipedia.org/w/index.php?title=Programme_Alsat&oldid=181325490, Portail:Information géographique/Articles liés, licence Creative Commons attribution, partage dans les mêmes conditions, comment citer les auteurs et mentionner la licence, Résolution en mode panchromatique(TDI) : 2,5, Résolution en mode multi-spectral (4 bandes couleur) : 10. - 4 Reaction Wheels (0.12 Nms) Figure 14: Identification and delimitation of burned zones acquired by AlSat-2A on September 6, 2014 in the Oued Soudane Forest (image credit: ASAL, W.Skikda), • The AlSat-2A spacecraft and its payload are operating nominally in 2013. All the elements are designed to cope with a multi-modules implementation capability. All secondary payloads were deployed into an orbit of 670 km altitude. Il a pour objectif principal la gestion des ressources naturelles du territoire algérien. The filters feature high band transmission, and sharp spectral band edges as illustrated in Figure 21. Figure 2: AstroSat 100 platform with mechanical accommodation of elements (image credit: Astrium SAS) 8). Alsat-1B est un microsatellite d'observation de la Terre de moyenne résolution construit utilisant une plate-forme SSTL-100[5]. The AlSat-2A spacecraft and its payload are operating nominally in the spring of 2017 - in their 7th year on orbit. • the ICM (Interface Control Module) encompasses the 64 Gbit mass memory and related FPGA (Floating Point Gate Array) based digital electronics and all the NAOMI housekeeping functions. Left: Estimated quaternion (12 hours observation). Now for the imaging mode and with the agility as a key feature, ALSAT-2B carries out the maneuvers to reach 30 deg either being along track or cross track. Alsat-1B est le deuxième satellite algérien d’observation de la terre à moyenne résolution, lancé par l’Algérie après Alsat-1. - Storage memory : 64 to 79 Gbit BOL – no compression, - Spacecraft launch mass: 116 kg - MCO (Mode Controle d'Orbite) or Orbit Control Mode, dedicated to orbit control maneuvers; it uses a set of 4 thrusters. AlSat-2B (117 kg) carries the NAOMI (New AstroSat Optical Modular Instrument). Figure 1: Artist's rendition of the AlSat-2 spacecraft (image credit: EADS Astrium SAS), AlSat-2 is the first Earth observation satellite system of the AstroSat-100 (AS-100) family; the design is based on the Myriade platform of CNES (Myriade heritage of CNES DEMETER and Parasol missions, plus four Essaim microsatellites built by EADS Astrium for DGA, France). Launch: AlSat-2A was launched as a secondary payload on July 12, 2010 on a PSLV launcher (PSLV-C15). The goal of BlackSky Global is to build a constellation of 60 satellites by 2019. As actuators, there is three magnetorquers used for detumbling at the beginning, after that they will be used for wheel unloading. Right: Estimated angular rate (12 hours observation), image credit: ASAL. The geocentric pointing applies during the eclipse phase or when the satellite is in imaging or downloading modes, Figure 11 illustrates the different satellite pointing capabilities. Le satellite a une masse de 103 kg. Concernant Alsat-2B, jumeau d’Alsat-2A, ce satellite a déjà fourni, durant sa première année d’exploitation, plus de 24.300 images élémentaires couvrant tous les continents, ce qui représente une longueur totale d’images acquises de plus de 208.352km, une surface couverte de plus de 3… According to these observed results where there are different maneuvers and transitions from day to night and back that are well represented by the angular rates (see Figure 9, right), we can say that the gyro stellar performances are acceptable with respect to the requirements, due to a better robustness of the SST tracking loss and a better on-board autonomy. 14). Mis en orbite par le lanceur indien PSLV-C 35 le 26 septembre 2016, pour une durée de vie nominale de cinq (05) ans, le satellite … The MEV provides the F2EM with the primary power supplies and clocks necessary to front-end operation. En effet, le lanceur PSLV C-35 de l’agence spatiale indienne (ISRO) a mis en orbite 8 satellites, dont 3 satellites algériens, précise l’agence dans un communiqué. The system will enable Algeria to obtain very high quality images for use in a wide variety of applications: cartography, management of agriculture, forestry, water, mineral and oil resources, crop protection, management of natural disasters and land planning. Alsat-2A, est un satellite d'observation de la Terre à haute résolution, il a été intégré et testé en France, dans les locaux d'EADS Astrium avec la participation de 29 ingénieurs algériens. - 2 S-band transceivers for communication (CCSDS, 20 kbit/s TC, 25-384 kbit/s TM), - X band downlink: 60 Mbit/s The Algerian government created its Space Agency in January 2002, ASAL (Agence Spatiale Algérienne) or Algerian Space Agency, to develop, promote, and manage the countries space program. Antrix Corporation Ltd. of Bangalore, India, is the launch provider and marketing arm of ISRO (Indian Space Research Organization). The idea is to fuse sensors with complementary measure properties to combine their desired and cancel out their unwanted characteristics. PISAT is a joint initiative of PES University and five other colleges. Figure 3: Illustration of the AlSAT-2 spacecraft (image credit: EADS Astrium SAS), Aluminum bus structure, Size: 60 cm x 60 cm x 100 cm, AOCS (Attitude & Orbit Control Subsystem), - Magnetic autonomous acquisition 25), Figure 15: Global view of the town of Skikda with industrial zone observed with AlSat-2A at a resolution of 2.5 m (image credit: CNTS, ASAL) 26), Figure 16: Sample image of NAOMI observed in October 2010 located near Skikda in north eastern Algeria (image credit: CNTS, ASAL). All the stringent constraints of dynamic range optimization and power consumption reduction have been mastered with < 1 watt detector dissipation. An example is given in Figure 13. Alsat-1 C'est le premier satellite artificiel algérien. Background: AlSat-1 of CNTS is being flown in the DMC (Disaster Monitoring Constellation), a 5 spacecraft optical imaging constellation developed and coordinated by SSTL (Surrey Satellite Technology Ltd), UK. The attitude determination during the nominal mode is carried out by three gyroscopes and a star tracker. Sensor fusion generally refers to the process of combining measurements from several different sensors in order to obtain a better result than considering each sensor separately. B Benbouzid, J. J Arnoux, E. Chinal, C Massol, P. Rouchit(1), S. de Zotti, "NAOMI instrument: a product line of compact & versatile cameras designed for high resolution missions in Earth observation," Proceedings of the 7th ICSO (International Conference on Space Optics) 2008, Toulouse, France, Oct. 14-17, 2008, 30) Information provided by Hervé Lambert of EADS Astrium SAS, Toulouse, France. AISSat-1 was built by UTIAS/SFL (University of Toronto, Institute for Aerospacestudies/Space Flight Laboratory), Toronto, Canada. - The mirror surface can to be polished down to a roughness of a few angstrom (1Å= 10-10 m). 19), • Feb. 2015: AlSat-2A is operational. In Feb. 2006, CNTS signed an agreement with EADS Astrium SAS to design and built two satellites. Il a pour objectif principal la gestion des ressources naturelles. 21) The high-resolution imagery allows Algeria to improve and update the base and thematic mapping throughout the national territory. Orbit: Sun-synchronous orbit of SCATSat-1, altitude = 720 km, inclination = 98.1º, LTAN = 9:30 hours. En effet, l’Algérie qui dispose actuellement de 5 satellites (trois dans le domaine de l’observation de la terre, un de démonstration technologique et un autre de télécommunications) vient encore une fois de démontrer sa maitrise de la technologie spatiale. The SST innovations and the estimated gyro drifts are illustrated in figures 9 and 10 where it can be seen clearly the effect of the earth blinding gaps on the SST innovations, a peak value occurs each time at the end of the earth blinding, no gyro drift calculation are done on this moment and the estimator will propagate the attitude. - During the nominal mode, ALSAT-2B is being pointed either toward sun (heliocentric pointing) or toward earth (geocentric pointing). Figure 9: 02 March 2019, with mission plan uploaded. Alsat-1 est arrivé en fin de vie le 15 août 2010. Alsat-2B est le deuxième satellite d'observation de la terre à haute résolution lancé le 26 septembre 2016 après Alsat-2A lancé en juillet 2010. It should be noticed here that along these two years, the obtained results fulfill the requirements and all of them fall under the specifications. It consists of two main parts: • the MEV is in charge of frontend operation, video processing, A/D conversion and transmission to the ICM via very high-speed digital link. L'Agence spatiale algérienne (en arabe الوكالة الفضائية الجزائرية), également désignée par son acronyme ASAL, est l'agence spatiale responsable du Il fait partie de la famille de satellites Disaster Monitoring Constellation (DMC) développés par la société Surrey Satellite Technology Ltd (SSTL). 13). Spacecraft Launch Mission Status Sensor Complement References Back to top, Observation of the Earth and its Environment.