Literatura académica sobre el tema "Autonomous satellites"
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Artículos de revistas sobre el tema "Autonomous satellites"
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Gao, Youtao, Tanran Zhao, Bingyu Jin, Junkang Chen y Bo Xu. "Autonomous Orbit Determination for Lagrangian Navigation Satellite Based on Neural Network Based State Observer". International Journal of Aerospace Engineering 2017 (2017): 1–10. http://dx.doi.org/10.1155/2017/9734164.
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In order to improve the accuracy of the dynamical model used in the orbit determination of the Lagrangian navigation satellites, the nonlinear perturbations acting on Lagrangian navigation satellites are estimated by a neural network. A neural network based state observer is applied to autonomously determine the orbits of Lagrangian navigation satellites using only satellite-to-satellite range. This autonomous orbit determination method does not require linearizing the dynamical mode. There is no need to calculate the transition matrix. It is proved that three satellite-to-satellite ranges are needed using this method; therefore, the navigation constellation should include four Lagrangian navigation satellites at least. Four satellites orbiting on the collinear libration orbits are chosen to construct a constellation which is used to demonstrate the utility of this method. Simulation results illustrate that the stable error of autonomous orbit determination is about 10 m. The perturbation can be estimated by the neural network.
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Wang, Haihong, Zhonggui Chen, Jinjun Zheng y Haibin Chu. "A New Algorithm for Onboard Autonomous Orbit Determination of Navigation Satellites". Journal of Navigation 64, S1 (14 de octubre de 2011): S162—S179. http://dx.doi.org/10.1017/s0373463311000397.
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Autonomous orbit determination of a navigation constellation is the process by which the orbit parameters of navigation satellites are autonomously calibrated onboard the satellites without the need for external aids. It commonly uses a satellite onboard data processing unit and a filtering method to process the measurements of inter-satellite ranges. The onboard data processing unit is the main module of autonomous navigation systems. In this paper, the two main factors that affect the accuracy of autonomous orbit determination for a navigation constellation are discussed first, and then a distributed onboard algorithm for autonomous orbit determination of navigation satellites is proposed. This method is based on a long-term ephemeris prediction and is suitable for the satellite hardware capability. The main feature of this method is that both the distributed computing method and an onboard analytical state transition matrix are used to process inter-satellite range measurements. One of the main advantages of this approach is high-speed computing since the amount of calculations needed is significantly less than that of the centralised computing method and those distributed methods that need to use an onboard numerical integrator. Another advantage of this approach is that the use of the onboard analytical state transition matrix algorithm can save a great amount of resources for both ground-to-satellite data transmissions and data storage units in satellites’ hardware. This could result in substantial cost reduction for space missions. Finally, a simulation method used for testing the proposed algorithm is presented. Results of tests over a period of 90 days show that the user range error of autonomous orbit determination derived from the proposed method is less than three metres.
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Li, Muzi, Bo Xu y Jun Sun. "Autonomous Orbit Determination for a Hybrid Constellation". International Journal of Aerospace Engineering 2018 (26 de septiembre de 2018): 1–13. http://dx.doi.org/10.1155/2018/4843061.
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A new orbit determination scheme targeting communication and remote sensing satellites in a hybrid constellation is investigated in this paper. We first design one such hybrid constellation with a two-layer configuration (LEO/MEO) by optimizing coverage and revisit cycle. The main idea of the scheme is to use a combination of imagery, altimeter data, and inter-satellite range data as measurements and determine orbits of the satellites in the hybrid constellation with the help of the extended Kalman filter (EKF). The performance of the new scheme is analyzed with Monte Carlo simulations. We first focus on an individual remote sensing satellite and compared the performance of orbit determination using only imagery with its counterpart using both imagery and altimeter measurements. Results show that the performance improves when imagery is used with altimeter data pointing to geometer calibration sites but declines when used with ocean altimeter data. We then expand the investigation to the whole constellation. When inter-satellite range data is added, orbits of all the satellites in the hybrid constellation can be autonomously determined. We find that the combination of inter-satellite range data with remote sensing observations lead to a further improvement in orbit determination precision for LEO satellites. Our results also show that the performance of the scheme would be affected when remote sensing observations on certain satellites are absent.
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Kitamura, Mitsunori, Yoichi Yasuoka, Taro Suzuki, Yoshiharu Amano y Takumi Hashizume. "Path Planning for Autonomous Vehicles Using QZSS and Satellite Visibility Map". Journal of Robotics and Mechatronics 25, n.º 2 (20 de abril de 2013): 400–407. http://dx.doi.org/10.20965/jrm.2013.p0400.
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This paper describes a path planning method that uses the Quasi-Zenith Satellites System(QZSS) and a satellite visibility map for autonomous vehicles. QZSS is a positioning system operated by Japan that has an effect similar to an increase in the number of GPS satellites. Therefore, QZSS can be used to improve the availability of GPS positioning. A satellite visibility map is a special map that simulates the number of visible satellites at all points on the map. The vehicle can use the satellite visibility map to determine the points that receive more satellite signals. The proposed method generates the artificial potential fields from the satellite visibility map and obstacle information around the vehicle, and it generates the path following the potential fields. Thereby, the vehicle can select the path that has more satellite signals, improving the availability of GPS fixed solutions. Hence, the vehicle can reduce the accumulated error by dead reckoning, and it can improve the safety of self-control. In this study, we evaluate the satellite visibility maps and the path planning method. The results show that the proposed method does improve the availability of GPS fixed solutions.
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Mcinroy, J., L. Robertson y R. Erwin. "Autonomous distant visual silhouetting of satellites". IEEE Transactions on Aerospace and Electronic Systems 44, n.º 2 (abril de 2008): 801–8. http://dx.doi.org/10.1109/taes.2008.4560222.
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Alfonso, Màrius Josep Fullana i., Diego Pascual Sáez Milán, Josep Vicent Arnau i. Córdoba y Neus Puchades Colmenero. "Some Improvements on Relativistic Positioning Systems". Applied Mathematics and Nonlinear Sciences 3, n.º 1 (13 de mayo de 2018): 161–66. http://dx.doi.org/10.21042/amns.2018.1.00012.
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AbstractWe make some considerations about Relativistic Positioning Systems (RPS). Four satellites are needed to position a user. First of all we define the main concepts. Errors should be taken into account. Errors depend on the Jacobian transformation matrix. Its Jacobian is proportional to the tetrahedron volume whose vertexes are the four tips of the receiver-satellite unit vectors. If the four satellites are seen by the user on a circumference in the sky, then, the Jacobian and the tetrahedron volume vanish. The users we consider are spacecraft. Spacecraft to be positioned cannot be close to a null Jacobian satellites-user configuration. These regions have to be avoided choosing an appropriate set of four satellites which are not seen too close to the same circumference in the sky. Errors also increase as the user spacecraft separates from the emission satellite region, since the tetrahedron volume decreases.We propose a method to autonomously potion a user-spacecraft which can test our method. This positioning should be compared with those obtained by current methods. Finally, a proposal to position a user-spacecraft moving far from Earth, with suitable devices (autonomous), is presented.
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Suzuki, Taro, Mitsunori Kitamura, Yoshiharu Amano y Nobuaki Kubo. "Autonomous Navigation of a Mobile Robot Based on GNSS/DR Integration in Outdoor Environments". Journal of Robotics and Mechatronics 26, n.º 2 (20 de abril de 2014): 214–24. http://dx.doi.org/10.20965/jrm.2014.p0214.
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This paper describes the development of a mobile robot system and an outdoor navigationmethod based on global navigation satellite system (GNSS) in an autonomous mobile robot navigation challenge, called the Tsukuba Challenge, held in Tsukuba, Japan, in 2011 and 2012. The Tsukuba Challenge promotes practical technologies for autonomous mobile robots working in ordinary pedestrian environments. Many teams taking part in the Tsukuba Challenge used laser scanners to determine robot positions. GNSS was not used in localization because its positioning has multipath errors and problems in availability. We propose a technique for realizing multipath mitigation that uses an omnidirectional IR camera to exclude “invisible” satellites, i.e., those entirely obstructed by a building and whose direct waves therefore are not received. We applied GPS / dead reckoning (DR) integrated based on observation data from visible satellites determined by the IR camera. Positioning was evaluated during Tsukuba Challenge 2011 and 2012. Our robot ran the 1.4 km course autonomously and evaluation results confirmed the effectiveness of our proposed technique and the feasibility of its highly accurate positioning.
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Liao, Shilong, Zhaoxiang Qi y Zhenghong Tang. "A Differential Measurement Method for Solving the Ephemeris Observability Issues in Autonomous Navigation". Journal of Navigation 68, n.º 6 (25 de mayo de 2015): 1133–40. http://dx.doi.org/10.1017/s0373463315000417.
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The autonomous navigation of navigation and positioning systems such as the Global Positioning System (GPS) and other Global Navigation Satellite Systems (GNSS) was motivated to improve accuracy and survivability of the navigation function for 180 days without ground contact. These improvements are accomplished by establishing inter-satellite links in the constellation for pseudo-range observations and communications between satellites. But observability issues arise for both ephemeris and clock since the pseudo-range describes only the relative distance between satellites. A differential measurement method is proposed to measure the rotation of the constellation as a whole for the first time. The feasibility of the proposed method is verified by simulations.
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Liu, Li, Wei Zheng y Guojian Tang. "Autonomous Positioning of Satellite Constellations via X-ray Pulsar Measurements". Journal of Navigation 66, n.º 5 (21 de junio de 2013): 671–82. http://dx.doi.org/10.1017/s0373463313000325.
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A novel autonomous positioning approach based on X-ray pulsars is proposed in this paper. First, the principles of the pulsar–based measurement model and the inter-satellite range model in the autonomous positioning of satellite constellations are presented. The observability of the pulsar-based measurement model is then shown. Second, the autonomous positioning algorithms, including measurement models and orbital dynamics models, are formulated using an unscented Kalman filter to estimate the position vectors of satellites. Finally, the feasibility of the proposed measurement scheme compared with an inter-satellite range scheme is illustrated by numerical simulation. The results show that the proposed approach can keep the satellite state convergent, and achieve position accuracies of 2 m. The proposed scheme provides a promising approach for autonomous absolute positioning of constellation systems by using X-ray pulsars.
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Ning, Xiaolin, Xin Ma, Cong Peng, Wei Quan y Jiancheng Fang. "Analysis of Filtering Methods for Satellite Autonomous Orbit Determination Using Celestial and Geomagnetic Measurement". Mathematical Problems in Engineering 2012 (2012): 1–16. http://dx.doi.org/10.1155/2012/267875.
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Satellite autonomous orbit determination (OD) is a complex process using filtering method to integrate observation and orbit dynamic equations effectively and estimate the position and velocity of a satellite. Therefore, the filtering method plays an important role in autonomous orbit determination accuracy and time consumption. Extended Kalman filter (EKF), unscented Kalman filter (UKF), and unscented particle filter (UPF) are three widely used filtering methods in satellite autonomous OD, owing to the nonlinearity of satellite orbit dynamic model. The performance of the system based on these three methods is analyzed under different conditions. Simulations show that, under the same condition, the UPF provides the highest OD accuracy but requires the highest computation burden. Conclusions drawn by this study are useful in the design and analysis of autonomous orbit determination system of satellites.
Tesis sobre el tema "Autonomous satellites"
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Anderson, Jason Lionel. "Autonomous Satellite Operations For CubeSat Satellites". DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/256.
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In the world of educational satellites, student teams manually conduct operations daily, sending commands and collecting downlinked data. Educational satellites typically travel in a Low Earth Orbit allowing line of sight communication for approximately thirty minutes each day. This is manageable for student teams as the required manpower is minimal. The international Global Educational Network for Satellite Operations (GENSO), however, promises satellite contact upwards of sixteen hours per day by connecting earth stations all over the world through the Internet. This dramatic increase in satellite communication time is unreasonable for student teams to conduct manual operations and alternatives must be explored. This thesis first introduces a framework for developing different Artificial Intelligences to conduct autonomous satellite operations for CubeSat satellites. Three different implementations are then compared using Cal Poly's CP6 CubeSat and the University of Tokyo's XI-IV CubeSat to determine which method is most effective.
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Santiago, Luis. "AUTONOMOUS CONTROLS ALGORITHMFOR FORMATION FLYING OF SATELLITES". Master's thesis, University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2641.
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This document describes the design and analysis of the Navigation, Guidance and Control System for the KnightSat project. The purpose for the project is to test and demonstrate new technologies the Air Force would be interested in for research and development. The primary mission of KnightSat is to show how a constellation of satellites can maintain relative position with each other autonomously using the Microwave Electro Thermal (MET) thruster. The secondary mission is to use multiple satellite imagery to obtain 3 dimensional stereo photographs of observable terrain. Formation flying itself has many possible uses for future applications. Selected missions that require imaging or data collection can be more economically accomplished using smaller multiple satellites. The MET thruster is a very efficient, but low thrust alternative that can provide thrust for a very long time, hence provide the low thrust necessary to maintain the satellites at a constant separation. The challenge is to design a working control algorithm to provide the desired output data to be used to command the MET thrusters. The satellites are to maintain a constant relative distance from each other, and use the least amount of fuel possible. If one satellite runs out of fuel before the other, it would render the constellation less useful or useless. Hence, the satellites must use the same amount of fuel in order to maintain an optimal operational duration on orbit.M.S.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Aerospace Engineering
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Badger, Stanley. "Autonomous detection, navigation, and propulsion for satellites". Kansas State University, 2009. http://hdl.handle.net/2097/1402.
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Master of ScienceDepartment of Electrical and Computer Engineering
William B. Kuhn
With the increasing number of satellites and space debris in all orbits the need for individual satellites to be able to autonomously detect and determine methods to navigate around them is increasing. Even with continued input and control from a ground station, the ability for a satellite to act to save itself from obstacles not visible from ground stations, or if communications were temporarily lost could be key to saving millions of dollars in hardware as well as improving overall performance and operational lifetimes.
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Ruiz-de-Azua, Ortega Joan Adrià. "Contribution to the development of autonomous satellite communications networks : the internet of satellites". Doctoral thesis, Universitat Politècnica de Catalunya, 2020. http://hdl.handle.net/10803/671780.
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The space is experiencing a revolution due to the em ergence of satellite services to satisfy environmental, socio-econom ic, and geo-political demands. Earth Observation satellite systems have become dependable resources for climate monitoring,
modern agriculture, and other applications. The 5G incursion in the aerospace domain has promoted the satellites as promising platforms to achieve global coverage, and cope the limitations of ground facilities. These demands can be
summarized in two system requirements: (1) increase of data transfer capacity, and (2) decrease of end-to-end
com m unications latency. Distributed Satellite Systems have emerged as an effective solution of m ultiple satellites operating simultaneouslyto satisfycommon requirements. Federated Satellite Systems are serious candidates to exploit the potential of distributed architectures by establishing opportunistic collaborations among satellites to share unallocated resources. These collaborations, called federations, allows to conceive the space as a cloud in which satellites leverage from other resources to improve their performance. The successive investigations have been centered on developing novel federation technologies. However, multiple design aspects are still open fields of study, such as the development of communications capabilities to establish these federations. This dissertation contributes to fill this gap bydefining mechanisms to deploy a network infrastructure for this purpose. A networked environment in which satellites are able to establish sporadically, and opportunisticallyfederations has been discussed. This context is called the Internet of Satellites paradigm, and prometes the temporal deployment of inter-satellite networks, composed of heterogeneous satellites. This feature---with satellite motion--poses a challenge on the definition of end-to-end communications routes composed of intermediate satellites. Areview of current routing protocols from other satellite networks is conducted to identify the ideal protocol for these dynam ic networks. The outcome remarks the need to combine capabilities from different domains to achieve the desired performance. Among them, the capabilityto predict future inter-satellite links becomes crucial to mitigate the fragmentation of the network. With this prem ise in mind, this dissertation presents a predictive protocol that perform s the estimation of these inter-satellite contacts in a distributed manner. This new satellite capability may support the routing protocol by allowing the estimation of future routes as a sequence of satellite contacts over time. The research presented in this dissertation also tackles other questions that remained unanswered: How can satellites be aware of the available resources offered by other satellites? What are the necessary mechanisms to deploy a federation? A software stack with two protocols to deal with this technology gap has been developed. The Opportunistic Service Availability Dissem ination Protocol allows notifying the services that are available in a satellite, while the Federation Deploym ent Control Protocol form alizes the rules to establish and m anage a federation. The application of these protocols considerably enhancded the capabilityof the satellite system to download data, becom ing thus enablers of future satellite m issions. The achieved perform anee has motivated the developm ent of a dedicated system. 11 has been named Federated Satellite Systems Experiment payload, and includes a communications device to create inter-satellite links. This system has been verified in a stratospheric balloon campaign, and integrated in a CubeSat miss ion. This dissertation discusses the results of the campaign, which emphasize the benefits and viabilityof this implementation. We expect that the contributions of this dissertation mayencourage to keep investigating on this inter-satellite communications for satellite federations.L'espai esta experimentant! una revolució degut a l'aparició de serveis per satèl·lit que satisfan les noves demandes ambientals, socials i geo-polítiques. Els sistemes de satèl·lits per observar la Terra han esdevingut recursos essencials per el control del clima, !'agricultura moderna, i altres aplicacions. L'entrada del 5G en el sector aeroespacial ha promogut els satèl·lits com plataformes per aconseguir una cobertura global. Aquestes necessitats poden ser classificades en dos requeriments de sistema: (1) L'augment de la capacitat per transferir dades, i (2) la reducció de la latència en les comunicacions d'extrem-a-extrem. Els sistemes distribuïts de satèl·lits han esdevingut una solució efectiva amb múltiples satèl·lits essent operats simultàniament per satisfer uns requeriments comuns. Els sistemes federats de satèl·lits són candidats prometedors per explotar el potencial de les arquitectures distribuïdes mitjançant col·laboracions oportunistiques entre satèl·lits per compartir recursos. Aquestes col·laboracions, anomenades federacions, permeten concebre l'espai com un entorn on els satèl·lits poden beneficiar-se dels recursos d'altres per millorar el seu funcionament. Les investigacions s'han central en desenvolupar noves tecnologies per aquestes federacions. No obstant, molts aspectes de disseny encara són punts oberts de recerca, com ara el desenvolupament de protocols de comunicació per establir aquestes federacions. Aquesta tesina contribueix definint mecanismes que permeten desplegar una infraestructura en xarxa per establir federacions. A més a més, es discuteix sobre aquest context interconnectat on els satèl·lits poden establir esporàdicament i oportunísticament les federacions. Aquest escenari s'ha anomenat la Internet dels Satèl·lits, i promou els desplegament temporal de xarxes entre satèl·lits heterogenis. Aquesta característica, amb el moviment dels satèl·lits, suposa un repte en la definició de rutes entre extrems formades per satèl·lits intermitjos. Una revisió de protocols d'enrutament actuals d'altres xarxes de satèl·lits s'ha realitzat per identificar el protocol ideal per aquest tipus de xarxa dinàmica. El resultat remarca la necessitat de combinar capacitats de diferents dom in is per aconseguir el funcionament desitjat. Entre aquestes, la capacitat de preveure futurs enllaços entre satèl·lits esdevé crucial per mitigar la fragmentació de la xarxa. Amb aquesta premissa, aquesta tesina presenta un protocol predictiu que estima aquests contactes entre satèl·lits de forma distribuïda. Aquesta nova capacitat pot complementar el protocol d'enrutament mitjançant l'estimació de futures rutes com seqüències of contactes de satèl·lits a través del temps. La recerca presentada en aquesta tesina també respon altres preguntes que no s'havien res post encara: Com els satèl·lits poden descobrir els recursos disponibles en la xarxa? Quins són els mecanismes necessaris per establir i mantenir una federació? Una pila de protocols per cobrir aquesta necessitat tecnològica ha sigut desenvolupat. El protocol de dispersió de la disponibilitat de serveis oportunístics permet notificar els serveis disponibles en un satèl·lit, mentre que el protocol desplegament i control de federacions s'encarrega d'establir i gestionar les federacions. L'aplicació d'aquests protocols considerablement van realçar la capacita! del sistema de satèl·lit per descarregar dades, esdevenint així potenciadors de futures missions. Aquests resultats han motivat el desenvolupament d'un sistema dedica!, que inclou un dispositiu de comunicacions per crear enllaços entre satèl·lit. Aquest sistema ha estat verifica! en una campanya de globus estratosfèrics, i ha sigut integral en una missió de CubeSats. Aquesta dissertació presenta els resultats de la campanya, els quals emfasitzen els profits i viabilitat d'aquesta implementació.
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Salazar, Kardozo Alexandros. "A High-Level Framework for the Autonomous Refueling of Satellite Constellations". Thesis, Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14534.
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Satellite constellations are an increasingly attractive option for many commercial and military applications. They provide a robust and distributed method of accomplishing the goals of expensive monolithic satellites. Among the many challenges that satellite constellations engender (challenges in control, coordination, disposal, and other areas), refueling is of particular interest because of the many methods one can use to refuel a constellation and the lifetime implications on the satellites.
The present work presents a methodology for carrying out peer-to-peer refueling maneuvers within a constellation. Peer-to-peer (P2P) refueling can be of great value both in cases where a satellite unexpectedly consumes more fuel than it was alloted, and as part of a mixed refueling strategy that will include an outside tanker bringing fuel to the constellation. Without considering mixed-refueling, we formulate the peer-to-peer refueling problem as an assignment problem that seeks to guarantee that all satellites will have the fuel they need to be functional until the next refueling, while concurrently minimizing the cost in fuel that the refueling maneuvers entail. The assignment problem is then solved via auctions, which, by virtue of their distributed nature, can easily and effectively be implemented on a constellation without jeopardizing any robustness properties.
Taking as a given that the P2P assignment problem has been solved, and that it has produced some matching among fuel deficient and fuel sufficient satellites, we then seek to sequence those prescribed maneuvers in the most effective manner. The idea is that while a constellation can be expected to have some redundancy, enough satellites leaving their assigned orbital slots will eventually make it impossible for the constellation to function. To tackle this problem, we define a wide class of operability conditions, and present three algorithms that intelligently schedule the maneuvers. We then briefly show how combining the matching and scheduling problems yields a complete methodology for organizing P2P satellite refueling operations.
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Martinson, Nicholas S. "Obstacle avoidance guidance and control for autonomous satellites". [Gainesville, Fla.] : University of Florida, 2009. http://purl.fcla.edu/fcla/etd/UFE0041033.
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Hashida, Yoshikazu. "Analytical solution for autonomous determination of near circular orbits". Thesis, University of Surrey, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274353.
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Aorpimai, Manop. "Low-thrust orbit control of LEO small satellites". Thesis, University of Surrey, 2000. http://epubs.surrey.ac.uk/843024/.
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In this thesis, we investigate the orbit control strategies of small satellites in Low Earth Orbits (LEO) where the disturbance effects are significant, in particular the nonspherical Earth and atmospheric drag effects. These orbits are not suitable to be controlled by using traditional ground-based control strategies which generally require high-thrust propulsion systems and other expensive resources, both onboard and in the ground segment. In order to react to those disturbances spontaneously and keep a small satellite at a pre-defined station using its limited resources, autonomous orbit control technology needs to be enabled. With the current advances in navigation and propulsion technology, as well as onboard computation systems, the only key issue that needs further investigations for practical implementation of an autonomous orbit operation system is the control algorithm. The orbit control strategies we investigate here are treated separately for each of the orbital control phases, i.e. orbit deployment and acquisition, orbit transfer and orbit maintenance. We present various forms of the solutions of the epicycle motion which allow us to treat each control problem according to the control requirements, nature of perturbations, control time scales and available resources. Although applied in different manners, the optimal low-thrust control scheme is a common aim for all control problems investigated here, as we mainly focus upon applications for low cost small satellites in LEO. The verifications of the strategies proposed in this thesis have been demonstrated not only via computer simulations, but also successfully demonstrated on in-orbit small satellite platforms thanks to an active small satellite programme at Surrey Space Centre. The success of this study is hoped to provide a valuable basis for satellite orbit operations which will involve larger number of satellites with more complex configurations in the future.
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Nagarajan, N. "Autonomous Orbit Estimation For Near Earth Satellites Using Horizon Scanners". Thesis, Indian Institute of Science, 1994. http://hdl.handle.net/2005/155.
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Autonomous navigation is the determination of satellites position and velocity vectors onboard the satellite, using the measurements available onboard. The orbital information of a satellite needs to be obtained to support different house keeping operations such as routine tracking for health monitoring, payload data processing and annotation, orbit manoeuver planning, and prediction of intrusion in various sensors' field of view by celestial bodies like Sun, Moon etc. Determination of the satellites orbital parameters is done in a number of ways using a variety of measurements. These measurements may originate from ground based systems as range and range rate measurements, or from another satellite as in the case of GPS (Global Positioning System) and TDUSS (Tracking Data Relay Satellite Systems), or from the same satellite by using sensors like horizon sensor^ sun sensor, star tracker, landmark tracker etc. Depending upon the measurement errors, sampling rates, and adequacy of the estimation scheme, the navigation accuracy can be anywhere in the range of 10m - 10 kms in absolute location.
A wide variety of tracking sensors have been proposed in the literature for autonomous navigation. They are broadly classified as (1) Satellite-satellite tracking, (2) Ground- satellite tracking, (3) fully autonomous tracking. Of the various navigation sensors, it may be cost effective to use existing onboard sensors which are well proven in space. Hence, in the current thesis, the Horizon scanner is employed as the primary navigation sensor-. It has been shown in the literature that by using horizon sensors and gyros, a high accuracy pointing of the order of .01 - .03 deg can be achieved in the case of low earth orbits. Motivated by such a fact, the current thesis deals with autonomous orbit determination using measurements from the horizon sensors with the assumption that the attitude is known to the above quoted accuracies.
The horizon scanners are mounted on either side of the yaw axis in the pitch yaw plane at an angle of 70 deg with respect to the yaw axis. The Field Of View (FOV) moves about the scanner axis on a cone of 45 deg half cone angle. During each scan, the FOV generates two horizon points, one at the space-Earth entry and the other at the Earth-space exit. The horizon points, therefore, lie• on the edge of the Earth disc seen by the satellite. For a spherical earth, a minimum of three such horizon points are needed to estimate the angular radius and the center of the circular horizon disc. Since a total of four horizon points are available from a pair of scanners, they can be used to extract the satellite-earth distance and direction.These horizon points are corrupted by noise due to uncertainties in the Earth's radiation pattern, detector mechanism, the truncation and roundoff errors due to digitisation of the measurements. Owing to the finite spin rate of the scanning mechanism, the measurements are available at discrete time intervals. Thus a filtering algorithm with appropriate state dynamics becomes essential to handle the •noise in the measurements, to obtain the best estimate and to propagate the state between the measurements. The orbit of a low earth satellite can be represented by either a state vector (position and velocity vectors in inertial frame) or Keplerian elements. The choice depends upon the available processors, functions and the end use of the estimated orbit information. It is shown in the thesis that position and velocity vectors in inertial frame or the position vector in local reference frame, do result in a simplified, state representation. By using the f and g series method for inertial position and velocity, the state propagation is achieved in linear form.
i.e. Xk+1 = AXK
where X is the state (position, velocity) and A the state transition matrix derived from 'f' and 'g' series. The configuration of a 3 axis stabilised spacecraft with two horizon scanners is used to simulate the measurements.
As a step towards establishing the feasibility of extracting the orbital parameters, the governing equations are formulated to compute the satellite-earth vector from the four horizon points generated by a pair of Horizon Scanners in the presence of measurement noise. Using these derived satellite-earth vectors as measurements, Kalman filter equations are developed, where both the state and measurements equations are linear. Based on simulations, it is shown that a position accuracy of about 2 kms can be achieved. Additionally, the effect of sudden disturbances like substantial slewing of the solar panels prior and after the payload operations are also analysed. It is shown that a relatively simple Low Pass Filter (LPF) in the measurements loop with a cut-off frequency of 10 Wo (Wo = orbital frequency) effectively suppresses the high frequency effects from sudden disturbances which otherwise camouflage the navigational information content of the signal. Then Kalman filter can continue to estimate the orbit with the same kind of accuracy as before without recourse to re-tuning of covariance matrices.
Having established the feasibility of extracting the orbit information, the next step is to treat the measurements in its original form, namely, the non-linear form. The entry or exit timing pulses generated by the scanner when multiplied by the scan rate yield entry or exit azimuth angles in the scanner frame of reference, which in turn represents an effective measurement variable. These azimuth angles are obtained as inverse trigonometric functions of the satellite-earth vector. Thus the horizon scanner measurements are non-linear functions of the orbital state. The analytical equations for the horizon points as seen in the body frame are derived, first for a spherical earth case. To account for the oblate shape of the earth, a simple one step correction algorithm is developed to calculate the horizon points. The horizon points calculated from this simple algorithm matches well with the ones from accurate model within a bound of 5%. Since the horizon points (measurements) are non-linear functions of the state, an Extended Kalman Filter (EKF) is employed for state estimation. Through various simulation runs, it is observed that the along track state has got poor observability when the four horizon points are treated as measurements in their original form, as against the derived satellite-earth vector in the earlier strategy. This is also substantiated by means of condition number of the observability matrix. In order to examine this problem in detail, the observability of the three modes such as along-track, radial, and cross-track components (i.e. the local orbit frame of reference) are analysed. This difficulty in observability is obviated when an additional sensor is used in the roll-yaw plane. Subsequently the simulation studies are carried out with two scanners in pitch-yaw plane and one scanner in the roll-yaw plane (ie. a total of 6 horizon points at each time). Based on the simulations, it is shown that the achievable accuracy in absolute position is about 2 kms.- Since the scanner in the roll-yaw plane is susceptible to dazzling by Sun, the effect of data breaks due to sensor inhibition is also analysed. It is further established that such data breaks do not improve the accuracy of the estimates of the along-track component during the transient phase. However, filter does not diverge during this period.
Following the analysis of the' filter performance, influence of Earth's oblateness on the measurement model studied. It is observed that the error in horizon points, due to spherical Earth approximation behave like a sinusoid of twice the orbital frequency alongwith a bias of about 0.21° in the case of a 900 kms sun synchronous orbit. The error in the 6 horizon points is shown to give rise to 6 sinusoids. Since the measurement model for a spherical earth is the simplest one, the feasibility of estimating these sinusoids along with the orbital state forms the next part of the thesis. Each sinusoid along with the bias is represented as a 3 state recursive equation in the following form
where i refers to the ith sinusoid and T the sampling interval. The augmented or composite state variable X consists of bias, Sine and Cosine components of the sinusoids. The 6 sinusoids together with the three dimensional orbital position vector in local coordinate frame then lead to a 21 state augmented Kalman Filter. With the 21 state filter, observability problems are experienced. Hence the magnetic field strength, which is a function of radial distance as measured by an onboard magnetometer is proposed as additional measurement. Subsequently, on using 6 horizon point measurements and the radial distance measurements obtained from a magnetometer and taking advantage of relationships between sinusoids, it is shown that a ten state filter (ie. 3 local orbital states, one bias and 3 zero mean sinusoids) can effectively function as an onboard orbit filter. The filter performance is investigated for circular as well as low eccentricity orbits. The 10-state filter is shown to exhibit a lag while following the radial component in case of low eccentricity orbits. This deficiency is overcome by introducing two more states, namely the radial velocity and acceleration thus resulting in a 12-state filter. Simulation studies reveal that the 12-state filter performance is very good for low eccentricity orbits. The lag observed in 10-state filter is totally removed. Besides, the 12-state filter is able to follow the changes in orbit due to orbital manoeuvers which are part of orbit acquisition plans for any mission.
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Ramos, Bosch Pedro. "Improvements in autonomous GPS navigation of Low Earth Orbit satellites". Doctoral thesis, Universitat Politècnica de Catalunya, 2008. http://hdl.handle.net/10803/7019.
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Es defineix un satèl·lit d'òrbita baixa aquell que es troba a una alçada de fins a 2000 km per sobre de la superfície de la Terra. Degut al ràpid decaïment dels objectes propers a la superfície degut al fregament atmosfèric, s'accepta que l'alçada típica per un LEO esta entre 200 i 2000 km.Aquesta rang d'alçades fa que els LEO siguin utilitzats per un ampli rang d'aplicacions, com a repetidors de comunicacions, sensors remots, determinació gravimètrica i magnetomètrica, altimetria oceànica, determinació atmosfèrica i en operacions de Search and Rescue (Cerca i rescat). El seu posicionament precís és de gran importància per a poder complir correctament amb els seus objectius. En aquest sentit, una gran quantitat de satèl·lits LEO tenen un receptor GPS, que permet fer mesures GPS durant tot el seu recorregut al voltant de la Terra. Aquestes mesures poden ser utilitzades per determinar la trajectòria del satèl·lit. Aquesta operació es fa normalment a terra, després que el satèl·lit hagi transmès totes les mesures que ha pres. La capacitat de fer aquest posicionament en temps real a bord del satèl·lit és una necessitat per algunes aplicacions. El posicionament autònom es molt diferent del que es pot fer a terra, ja que el processador del satèl·lit te grans limitacions en recursos computacionals, per tant els complexos models i càlculs fets en un ordinador normal a terra, son completament excessius per un ordinador espacial. A més, alguns dels models utilitzats en l'estimació de la trajectòria necessiten dades addicionals (com activitat solar, o paràmetres de rotació de la Terra) que no son disponibles en temps real, per tant s'han de fer algunes aproximacions per tal de no necessitar cap d'aquestes dades. Aquesta tesis estudiarà la navegació autònoma amb GPS de satèl·lits LEO, tendència que esta incrementant la seva importància per les aplicacions tan científiques com tecnològiques que se'n poden derivar. La tesi desenvoluparà nous algoritmes i mètodes per obtenir una posició acurada i continua per LEOs. S'han cobert diferent aspectes:
· Mitigació de multipath e interferències. Les reflexions de senyals GPS en l'estructura del satèl·lit crea una distorsió que afecta la distància mesurada. La repetibilitat d'aquests efectes en relació amb l'orientació del satèl·lit pot ser utilitzat per a mitigar el seu impacte en la solució de navegació. S'han desenvolupat tècniques de mitigació de multipath i interferències per receptors d'una i de dos freqüències.
· Models dinàmics de forces. L'alta predictibilitat de la trajectòria d'objectes orbitant la Terra pot ser utilitzat en sinergia amb el GPS per a aconseguir solucions més precises que fent servir únicament GPS. Això s'utilitza normalment en estratègies en postprocess, però te grans requeriments computacionals, i necessita paràmetres no disponibles en temps real. La simplificació d'aquests models, i la supressió de paràmetres no disponibles es necessari per poder aplicar aquesta tècnica de processat en condicions de temps real.
· Maniobres. Els cossos en òrbita al voltant de la Terra no segueixen una trajectòria perfectament predeible. Hi han petites pertorbacions que modifiquen la seva trajectòria a llarg termini, i a més, el fregament atmosfèric frena poc a poc al satèl·lit, disminuint la seva alçada. Això fa necessari una correcció periòdica de la seva trajectòria, realitzat amb petits impulsos del sistema de propulsió del satèl·lit en lo que s'anomena una maniobra. Quan un satèl·lit es troba en una maniobra, deixa de seguir els models de caiguda lliure, per tant la maniobra s'ha de tenir en conte en l'estimació del filtre.
Tots els algoritmes i mètodes dissenyats han sigut testejats amb dades reals de diferents missions: SAC-C, CHAMP, JASON-1 i GRACE. S'han fet servir diversos tests cobrint diferents opcions de parametrització per tal d'avaluar el seu comportament.
Se define un satélite de órbita baja aquel que se encuentra en una altura de hasta 2000 km sobre la superficie terrestre. Debido al rápido decaimiento de los objetos cercanos a la superficie debido al fregamiento atmosférico se acepta que la altura típica para un LEO se sitúa entre 200 y 2000 km.
Este rango de alturas hace que los LEO sean utilizados para un amplio rango de aplicaciones como repetidores de comunicaciones, sensores remotos, determinación gravimétrica y magnetométrica, altimetría oceánica, determinación atmosférica y en operaciones de Search and Rescue (Búsqueda y rescate). Su posicionamiento preciso es de gran importancia para poder cumplir correctamente con sus objetivos. En este sentido, una gran cantidad de satélites LEO disponen de un receptor GPS, que permite realizar medidas GPS durante todo su recorrido alrededor de la Tierra. Estas medidas puede ser utilizadas para determinar la trayectoria del satélite. Esta operación se suele realizar en tierra, después que el satélite haya retransmitido todas las medidas que ha tomado. La capacidad de hacer este posicionamiento en tiempo real a bordo del satélite es una necesidad para algunas aplicaciones. El posicionamiento autónomo es muy diferente al que se puede realizar en tierra, ya que los procesadores de satélites tienen limitaciones en recursos computacionales, y por tanto los complejos modelos y cálculos realizados en un ordenador normal en tierra son excesivos para un ordenador espacial. Además, algunos de los modelos utilizados en la estimación de la trayectoria necesitan datos adicionales (como actividad solar, o parámetros de rotación de la Tierra) que no están disponibles en tiempo real, por lo que hay que realizar algunas aproximaciones para no necesitar ninguno de estos datos. Esta tesis estudiará la navegación autónoma mediante GPS en satélites LEO, tendencia que esta aumentando su importancia por las aplicaciones tanto científicas como tecnológicas que se pueden derivar. La tesis desarrollara nuevos algoritmos y métodos para obtener una posición precisa y continua para LEOs. Se han cubierto diferentes aspectos:
· Mitigación de multipath e interferencias. Las reflexiones de las señales GPS en la estructura del satélite crea una distorsión que afecta la distancia medida. La repetibilidad de estos efectos en relación con la orientación del satélite puede ser utilizado para mitigar su impacto en la solución de navegación. Se han desarrollado técnicas de mitigación de multipath e interferencias para receptores de una o dos frecuencias.
· Modelos dinámicos de fuerzas. La trayectoria de objetos orbitando la Tierra es muy predecible, lo cual puede ser usado en sinergia con GPS para conseguir posiciones más precisas que usando solo GPS. Esto se utiliza normalmente en estrategias en postproceso, pero tiene grandes necesidades computacionales, y requiere de parámetros no disponibles en tiempo real. La simplificación de estos modelos, y la supresión e esos parámetros es necesario para poder aplicar esta técnica de procesado en condiciones de tiempo real.
· Maniobras. Los cuerpos en órbita alrededor de la Tierra no siguen una trayectoria perfectamente predecible. Hay pequeñas perturbaciones que modifican su trayectoria a largo plazo. Además el fregamiento atmosférico frena poco a poco el satélite, reduciendo su altura. Esto hace que sea necesaria una corrección periódica de su trayectoria, realizado en pequeños impulsos por el sistema de propulsión del satélite en lo que se llama una maniobra. Cuando un satélite realiza una maniobra deja de comportarse según los modelos de caida libre, por tanto su maniobra se ha de tener en cuenta en la estimación del filtro. Todos los algoritmos y métodos diseñados han sido testeados con datos reales de diferentes misiones: SAC-C, CHAMP, JASON-1 y GRACE. Se han realizado un amplio abanico de tests cubriendo diferentes opciones de parametrización para evaluar su comportamiento.
Satellites in low Earth orbits (LEO) are generally defined to be up to an altitude of 2000 km above Earth's surface and given the rapid decay of objects on the lower altitude range due to atmospheric drag, it is commonly accepted that a typical LEO height lies between 200 and 2000 km. This altitude range makes LEO satellites useful for a wide range of applications such as communication transponders, remote sensing, gravimetric and magnetometric sounding, ocean altimetry, atmospheric retrieval and Search and Rescue alarm operations. Its accurate positioning is of great importance in the successful accomplishment of their objectives. In this sense, most LEO satellites have a GPS receiver, which allows to collect GPS measurements in its full revolution around the Earth. These measures can be used to precisely estimate the trajectory of the spacecraft. This operation is normally done on ground, after the satellite was able to downlink all the data it collected. The capacity to do this positioning in real-time onboard the satellite is a necessity for some of the applications, and would also allow a faster science product delivery.
This autonomous positioning is very different that the one that can be done on ground, as the satellite processor has large limitations in computational resources, so the complex models and calculus done in a normal computer on ground are completely unaffordable for the onboard processor. Besides, some of the models used in the trajectory estimation need some additional data (such as solar activity, or Earth rotation parameters) that are not available in real-time, so some approximations must be done to cope with these lack of data. This thesis will deepen into the study of autonomous GPS navigation of LEO satellites, a trend that is increasing its importance for their applications in both science and technological fields. It will develop new algorithms and methods in order to provide accurate and continuous positions for the satellites. Different aspects have been covered:
· Multipath and interference mitigation. Reflections of GPS signals in the spacecraft structure cause a distress that affects the measured distance. On the other hand, some spacecraft have more than one GPS antenna on its payload. This creates a cross-talk interference that also affects the measures. The repeatability of these effects in relation to the attitude of the spacecraft can be used to mitigate its impact into the final navigation solution. Multipath mitigation techniques have been developed for both single- and dual-frequency receivers.
· Dynamic force models. The high predictability of the trajectory of Earth orbiters is used in conjunction to GPS measurements to provide a more accurate solution than GPS standalone positions. This is a widely used technique in postprocessing strategies, but has high computational requirements and needs parameters not available in real-time. The simplifications of these models, along with the suppression of the parameters not available in an onboard environment is necessary to use these kind of positioning by a satellite processing in real-time conditions.
· Maneuver handling. Earth orbiters do not follow a fully predictable orbit, some low-order perturbations modifies its trajectory on the long term, and atmospheric drag slowly brakes the satellite, decreasing its altitude. This makes necessary a periodic correction of its trajectory.
This is done by short impulses produced by the satellite propulsion systems in what is called a maneuver. When a spacecraft is in a maneuver, it no longer follows the free-flight dynamic models, so this should be taken into account in the estimation filter. All the algorithms and methods have been tested with real data from different missions: SAC-C, CHAMP, JASON-1 and GRACE. Several test cases covering a wide range of days and parametrization options have been done in order to assess its performance.
Libros sobre el tema "Autonomous satellites"
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Farrell, James L. GNSS aided navigation & tracking: Inertially augmented or autonomous. Baltimore, Md: American Literary Press, 2007.
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Borah, Khireswar. Satellite autonomous councils of Assam & tribal law(s). Guwahati: Advanced Law & Allied Publishers Group, 2013.
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Flight Mechanics Symposium (1999 Goddard Space Flight Center). 1999 Flight Mechanics Symposium: Proceedings of a conference sponsored and held at NASA Goddard Space Flight Center, Greenbelt, Maryland, May 18-28, 1999. Washington, DC: National Aeronautics and Space Administration, 1999.
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Structural Emergence and the Collaborative Behavior of Autonomous Nano- Satellites. Storming Media, 1999.
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J, Priovolos George, Rhodehamel Harley, George C. Marshall Space Flight Center. y United States. National Aeronautics and Space Administration. Scientific and Technical Information Division., eds. Autonomous integrated GPS/INS navigation experiment for OMV: Phase I feasibility study. [Huntsville, Ala.?]: George C. Marshall Space Flight Center, 1989.
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Autonomous integrated GPS/INS navigation experiment for OMV: Phase I feasibility study. [Cleveland, Ohio]: George C. Marshall Space Flight Center, 1989.
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S, Border J. y Jet Propulsion Laboratory (U.S.), eds. Observation model and parameter partials for the JPL geodetic GPS modeling software "GPSOMC". Pasadena, Calif: National Aeronautics and Space Administration, Jet Propulsion Laboratory, California Institute of Technology, 1988.
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Garoche, Pierre-Loïc. Formal Verification of Control System Software. Princeton University Press, 2019. http://dx.doi.org/10.23943/princeton/9780691181301.001.0001.
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The verification of control system software is critical to a host of technologies and industries, from aeronautics and medical technology to the cars we drive. The failure of controller software can cost people their lives. This book provides control engineers and computer scientists with an introduction to the formal techniques for analyzing and verifying this important class of software. Too often, control engineers are unaware of the issues surrounding the verification of software, while computer scientists tend to be unfamiliar with the specificities of controller software. The book provides a unified approach that is geared to graduate students in both fields, covering formal verification methods as well as the design and verification of controllers. It presents a wealth of new verification techniques for performing exhaustive analysis of controller software. These include new means to compute nonlinear invariants, the use of convex optimization tools, and methods for dealing with numerical imprecisions such as floating point computations occurring in the analyzed software. As the autonomy of critical systems continues to increase—as evidenced by autonomous cars, drones, and satellites and landers—the numerical functions in these systems are growing ever more advanced. The techniques presented here are essential to support the formal analysis of the controller software being used in these new and emerging technologies.
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P, Lynch John y Goddard Space Flight Center, eds. 1999 Flight mechanics symposium. Greenbelt, Md: The Center, 1999.
Buscar texto completoCapítulos de libros sobre el tema "Autonomous satellites"
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Xie, Jun, Haihong Wang, Peng Li y Yansong Meng. "Autonomous Operation Technology of Navigation Satellites". En Space Science and Technologies, 331–77. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4863-5_9.
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Chao, Lu y Ren Fang. "Study on Autonomous Mission Management Method for Remote Sensing Satellites". En Wireless and Satellite Systems, 401–11. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-19153-5_42.
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Diris, J. P., J. Fourcade, C. Jayles, T. Tournier, L. Lefebvre, J. Dulac y N. Dubernet. "Autonomous Orbit Determination and Control in Constellations of Satellites". En Mission Design & Implementation of Satellite Constellations, 255–61. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5088-0_24.
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Jiang, Yu, Yiming Liu, Li Pan, Xiaojuan Li, Jin Huang y Fang Ren. "Extensible Autonomous Task Managing Strategy Suitable for Multi-loading Remote Sensing Satellites". En Lecture Notes in Electrical Engineering, 201–8. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4163-6_24.
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Liu, Peng y Xi-Yun Hou. "Combined Autonomous Orbit Determination of GEO/IGSO Satellites on the Space-Based Probe". En China Satellite Navigation Conference (CSNC) 2014 Proceedings: Volume III, 241–50. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-54740-9_22.
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Chen, Xi, Fang Ren, Shaohui Li, Quan Jing y Jun Dai. "Method of Earth-Observation-Satellites Autonomous Task Planning Based on Chronological Lookahead Algorithm". En Lecture Notes in Electrical Engineering, 360–68. Singapore: Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-4163-6_43.
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Wen, Xufeng, Jinming Hao, Xiaogong Hu, Chengpan Tang, Dongxia Wang, Jie Xin, Bo Jiao y Jing Wang. "Centralized Autonomous Orbit Determination of Beidou Satellites Under the Constraint of Anchor Station". En Lecture Notes in Electrical Engineering, 409–21. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0014-1_35.
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Liu, Bin, Xiyun Hou, Jingshi Tang y Lin Liu. "Autonomous Orbit Determination of Satellites Around Triangular Libration Points in the Earth–Moon System". En Proceedings of the 28th Conference of Spacecraft TT&C Technology in China, 113–30. Singapore: Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-4837-1_10.
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Wertz, James R., John T. Collins, Simon Dawson, Hans J. Königsmann y Curtis W. Potterveld. "Autonomous Constellation Maintenance". En Mission Design & Implementation of Satellite Constellations, 263–73. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-011-5088-0_25.
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Rubenstein, Michael y Zachary Manchester. "Bio-inspired Position Control of Satellite Constellations". En Distributed Autonomous Robotic Systems, 441–50. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-05816-6_31.
Texto completoActas de conferencias sobre el tema "Autonomous satellites"
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Wiens, Gloria J., Anake Umsrithong, Shawn Miller, Aneesh Koka y Travis Vitello. "Design of Autonomous Foldable Docking Mechanism for Small Space Vehicles". En ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-87678.
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Over the past decade, small satellites have gained the interest of the space industry as a new and cost effective approach for servicing space assets. To address the special constraints inherent to the component miniaturization required for these satellites, researchers in the Space, Automation and Manufacturing Mechanisms Laboratory (SAMM) are exploring foldable mechanisms and their effectiveness for providing autonomous rendezvous and docking capabilities for small space vehicles. This paper focuses particularly on the design of autonomous docking mechanisms for space vehicles within the small satellite class known as picosatellite (size and mass requirements: 1 kilogram mass within a 10×10×10 centimeter cube). The docking mechanisms deployment scenario is a dual satellite system comprised of two small satellites (a chaser and a target). The chaser has attitude and translational control capability, while the target is a passive satellite having only attitude stabilization capability. This paper will first present a review of the existing docking mechanism technology utilized in space. This is followed by details of a foldable mechanism approach for providing small satellites autonomous docking capabilities. This includes geometric and dynamic analysis conducted in ADAMS software simulations.
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Yu, Kuai, Fengjing Liu, Yunhe Liu y Guo Li. "Autonomous Decision-making for Satellites Surveillance". En 2019 Chinese Control And Decision Conference (CCDC). IEEE, 2019. http://dx.doi.org/10.1109/ccdc.2019.8832717.
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Madhusudhana, C. S., J. K. Kishore, R. Hulyal, A. V. Nirmal, S. V. Sharma y Mouilya Koka. "Autonomous power system for remote satellites". En 2017 Second International Conference on Electrical, Computer and Communication Technologies (ICECCT). IEEE, 2017. http://dx.doi.org/10.1109/icecct.2017.8117955.
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van Bezooijen, Roelof W. H. "Autonomous star trackers for geostationary satellites". En SPIE's 1996 International Symposium on Optical Science, Engineering, and Instrumentation, editado por Edward R. Washwell. SPIE, 1996. http://dx.doi.org/10.1117/12.254128.
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Okasha, Mohamed, Chandeok Park y Sang-Young Park. "Autonomous Multi Satellites Assembly in Keplerian Orbits". En AIAA Guidance, Navigation, and Control (GNC) Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2013. http://dx.doi.org/10.2514/6.2013-5195.
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Ledebuhr, A., J. Kordas, L. Ng, M. Jones, J. Whitehead, E. Breitfeller, R. Gaughan, M. Dittman y B. Wilson. "Autonomous, agile micro-satellites, and supporting technologies". En Space Technology Conference and Exposition. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1999. http://dx.doi.org/10.2514/6.1999-4537.
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Zagorski, P., A. Gallina, J. Rachucki, B. Moczala, S. Zietek y T. Uhl. "An orbit determination algorithm for small satellites based on the magnitude of the earth magnetic field". En Progress in Flight Dynamics, Guidance, Navigation, and Control – Volume 10, editado por C. Vallet, D. Choukroun, C. Philippe, A. Nebylov y M. Ganet. Les Ulis, France: EDP Sciences, 2018. http://dx.doi.org/10.1051/eucass/201810035.
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Autonomous attitude determination systems based on simple measurements of vector quantities such as magnetic field and the Sun direction are commonly used in very small satellites. However, those systems always require knowledge of the satellite position. This information can be either propagated from orbital elements periodically uplinked from the ground station or measured onboard by dedicated global positioning system (GPS) receiver. The former solution sacrifices satellite autonomy while the latter requires additional sensors which may represent a significant part of mass, volume, and power budget in case of pico- or nanosatellites. Hence, it is thought that a system for onboard satellite position determination without resorting to GPS receivers would be useful. In this paper, a novel algorithm for determining the satellite orbit semimajor-axis is presented. The methods exploit only the magnitude of the Earth magnetic field recorded onboard by magnetometers. This represents the first step toward an extended algorithm that can determine all orbital elements of the satellite. The method is validated by numerical analysis and real magnetic field measurements.
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CHEN, C., L. SLAFER y W. HUMMEL, JR. "Autonomous spin axis controller for geostationary spinning satellites". En Guidance, Navigation and Control Conference. Reston, Virigina: American Institute of Aeronautics and Astronautics, 1986. http://dx.doi.org/10.2514/6.1986-1984.
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He, Dong-lei y Xi-bin Cao. "Relative States Autonomous Determination of Satellites Formation Flying". En 2006 International Conference on Machine Learning and Cybernetics. IEEE, 2006. http://dx.doi.org/10.1109/icmlc.2006.258446.
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Zhang, Ai y Zhe Lin. "Modified SDREF for Ocean Observation Satellites Autonomous Navigation". En 2020 IEEE International Conference on Mechatronics and Automation (ICMA). IEEE, 2020. http://dx.doi.org/10.1109/icma49215.2020.9233797.
Texto completoInformes sobre el tema "Autonomous satellites"
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Ledebuhr, A. G. ,. LLNL. Autonomous, agile, micro-satellites and supporting technologies for use in low-earth orbit missions. Office of Scientific and Technical Information (OSTI), julio de 1998. http://dx.doi.org/10.2172/16731.
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White, R. L. y R. B. Gounley. Satellite Autonomous Navigation with SHAD (Stellar Horizon Atmospheric Dispersion). Fort Belvoir, VA: Defense Technical Information Center, abril de 1987. http://dx.doi.org/10.21236/ada184988.
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Hodgdon, Taylor, Anthony Fuentes, Jason Olivier, Brian Quinn y Sally Shoop. Automated terrain classification for vehicle mobility in off-road conditions. Engineer Research and Development Center (U.S.), abril de 2021. http://dx.doi.org/10.21079/11681/40219.
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The U.S. Army is increasingly interested in autonomous vehicle operations, including off-road autonomous ground maneuver. Unlike on-road, off-road terrain can vary drastically, especially with the effects of seasonality. As such, vehicles operating in off-road environments need to be in-formed about the changing terrain prior to departure or en route for successful maneuver to the mission end point. The purpose of this report is to assess machine learning algorithms used on various remotely sensed datasets to see which combinations are useful for identifying different terrain. The study collected data from several types of winter conditions by using both active and passive, satellite and vehicle-based sensor platforms and both supervised and unsupervised machine learning algorithms. To classify specific terrain types, supervised algorithms must be used in tandem with large training datasets, which are time consuming to create. However, unsupervised segmentation algorithms can be used to help label the training data. More work is required gathering training data to include a wider variety of terrain types. While classification is a good first step, more detailed information about the terrain properties will be needed for off-road autonomy.