Use of Sensors Technique in Astrology Free-Samples for Students

Question: Write a Research Paper on "Determination of attitude of satellite by using sun and earth sensor for increasing accuracy". Answer: Introduction Maintenance of the required orientations in space with required accuracy is the key mission of any astronomical objects. Attitude determination provides the avenue to do that. Attitude determination involves the use of mathematical models and sensors to make valuable spaceship inferences. The Earth magnetic fields are important in relation to satellite because they help establish components of inertia frame. Knowledge of absolute measurement of sensors of sun and Earth is valuable in identifying the position of the satellite in the orbit and makes it possible to calculate vector direction (Chang, Y. Yun, M. Lee, B. 2007, 345). Sun sensors are useful because all satellites can utilize them. The sun due to its brightness can be used as a reference point for astronomical objects. Majority of satellites use solar panels which makes it necessary to have correct directions in respect to the sun. Other satellites need to be protected from direct sunlight due to their sensitivity. The justifications are important when considering sun sensors usage during vector determinations and measurements. The satellites performance is affected by the Earth magnetic fields (Taraba et.al. 2009, 121). During determination of attitude of satellites the Earth sensors magnetic fields need to be considered to have accurate measurements. The sun sensors can measure radiations originating from the sun by functioning only through a sunlit phase of an orbit (Chang, Y. Yun, M. Lee, B. 2007, 467). Scientists and astrologists argue that the type of model of sun and Earth sensors to be used for specific satellites will depend on the positi oning of the sensor and identification of errors in order to obtain accurate results. This study will be aiming to establish the appropriate and accurate Sun and Earth sensors model to be used to determine the attitude of satellites. Literature review The section reviews the various methodologies, models and techniques related to study concepts Attitude measurements and its methodologies: Attitude measurements require control systems containing actuators and sensors. The measurement of the state of a system is done by using sensors any state while actuators are used for making adjustments in a control system (Taraba et.al 2009, 123). A satellite system uses sensors, actuators and mathematical models to correct vectors and make inferences on inertia movements. Any space craft attitude determination system uses sun vectors and Earth magnetic field vectors in coming up with algorithms (Grewal, M. Weill, L. Andrews, A. 2007, 123). The combination of the two results to attitude determination algorithms used to make rotation matrix. It is important that attitudes are measured accurately and effectively. There are two recognizable attitude measurement techniques the absolute and relative sensor measurements (Jensen, J. 2009, 25). Absolute measurement sensor states that knowing the satellite position in reference to the orbit enables one to calculate vectors in reference to the inertia frame of the astrological objects and how to counter Earths magnetic fields (Furgale, P. Enright, J. Barfoot, T. 2011, 1654). Absolute measurement sensors only measures direction in reference to space craft fixed body frame and making comparisons with inertia reference frame. In modern times the relative measurement sensors are represented by gyroscopic instruments (Springmann, J. Sloboda, A. Klesh, A. Bennet, M. Cutler, J. 2012, 210). Sun sensors: Sun sensors are valuable in attitude determination of satellites systems and control systems. The sun vector is useful elementary linear transformations that can be used in attitude determination formulations. The sun sensors provide two types of photocells this is single photo cells and pair of photo cells for measurements (Markley, F. Crassidis, J. 2014, 24). The main purpose of any sun sensor is to formulate an approximate value of vector covering the body reference frame facing the sun. The sun sensor performs by combining photocells which provides a complete unit of vector measurement. In determining the angle in respect to the normal sun sensor this arrangements results to photocells generating currents, to obtain suitable mathematical model it requires one to have a convenient algorithm that factors the current time expressed in a Julian time methodology (Ortega, P. Lopez, R. Ricart, J. Dominguez, M. Castaner, L. Quero, J. 2010, 2060). Magnetometers: the use of the tool measures magnetic field of a body frame. The magnetometer helps to guide vector measurements of the Earth magnetic field contained in body reference frame (Daz-Michelena, M. 2009, 2246). The mathematical model is needed to measure the magnetic field in body frame based on time and space crafts positions. The measurements of the direction of the Earth can be done using horizon sensors this is done by observing the shape of the Earth as seen in the satellite and comparing it with model shape (Slavinskis, A. et.al. 2014, 2341). hich depend upon complexity, reliability and expenses components. For example the sun sensors have an accuracy of 0.01o based on a typical field view of about 300. The Earth sensors accuracy is 0.050 (GEO) based on horizons uncertainties that dominate accuracy. The magnetometers accuracy is 1.00 (5000 km alt) which is based on the attitude measured relating to the Earths local magnetic field. The choice of sensor accuracy will vary with environmental characteristics, reduction of errors and sensor positioning (Daz-Michelena, M. 2009, 2245). Determining attitude of satellites: Determination of attitude of satellites is equivalent of establishing the rotation matrix by providing description of orientation of the satellite reference frame guided by the inertia frame. Proper balancing is required for direction of the sun and that of the Earth magnetic fields (Hill, K. Born, G. 2007, 681). The balancing is known as the rotation matrix. The application of triad algorithm is valuable in coming up with components of a vector the results is a rotational matrix that can be statistically be proven (Rufino, G. Grassi, M. 2009, 1510). Evaluation Different algorithms exist in applicability which makes decision making on the choices of sensors depending on pointing accuracy of the requirements. The use of sensors requires a in depth knowledge of the sensors and understanding percentage error models. Analysis of the Sun and Earth sensors models choices depends on the estimation algorithms usually carried out to assess measurement errors (Iwasaki, A., 2011, 262). In practice the sensors host errors that vary with satellite positions within the orbit, time and conditions of the place. It becomes difficult to estimate how the sun and Earth sensor can have a three axis creating an accuracy of 100. The development of sensor models accounts for several error sources that have kept astrologists to think upon better ways of mitigating them. Because the attitude determination of satellite is designed using three or more variables it makes the desired and measured states to be complicated. Understanding the concepts requires analysts to measure the body frame components and choose the right models to employ (Taraba, M. Rayburn, C. Tsuda, A. Mac, C. 2009, 126). Attitude determination is complicated which makes it necessary to have more than two vector measurements. The objective of the sun sensor is to produce an approximate unit order in respect the body references from the points of the sun which makes it necessary to identify the position of the Earth in its orbits to be able to obtain the necessary algorithms (Janson, S. Handy, B. Chin, A. Rumsey, D. Ehrlich, D Hinkley, D. 2012, 210). The sensor is depended upon a combination of four proto cells to provide a complete unit vector measurements instead of ignoring the errors there is an effort to develop realistic systematic error and noise models. Designing sensor models configurations is required for satellites (Shuster, M.D. Oh, S. 2012, 1456). A Gyro is required to measure any changes in attitude as opposed to absolute attitudes. The sun vector computation is depended upon elementary linear transformation to come up with better rotational matrix. The Earth imaging as seen development of small size and less costly satellites components, development of smaller gadgets has led to the need of having them perform accurately possible by having accurate attitude determination systems ( Inamori, T. Sako, N Nakasuka, S. 2011, 2040). The area of sensor use in attitude determination of satellite production is a new area that has seen several different sensors tested to achieve the intended better results. The sensors need to be relatively in expensive to enable the satellites to be relatively cheaper that will allow more usage of it and accessibility. Achieving an accurate attitude determination system is difficult because of factors like inertia, disturbances, and power consumption of difficult components. Majority of spacecraft use power which is difficult to manage or maintain. The study will seek find answer the following questions: Which attitude determination sensor method can be designed to be accurately be used in satellite usage? Which of the sun and Earth sensors models can be suitable to provide accurate results for attitude determination of satellites? How can errors and disturbances be minimized to increase the sun and earth accuracy levels? Conclusion The mission requirement of every spacecraft is to maintain a desired orientation space with the required level of accuracy. The work of astrologists is to use attitude determination to be able to control that. The level of accuracy targeted will vary, depending on the utility of the spacecraft, which provides the required selection of sensors and the attitude determination algorithm. Many formulation models are programmed to achieve the desired attitude determination subsystem for Low Earth Orbit satellites this is by use of sun sensor in order to achieve three-axis pointing accuracy requirement of about 0:10. The choice of sensors is guided by empirical data computed showing different levels of accuracy obtained through control system experiments. Mostly different satellite attitude determinations use a variety of sensors and actuators to achieve the required directions. Balancing of sensors is required to provide the required attitude variables and position of the satellite space. The complication of attitude determination arises on the fact that it cannot be underdetermined or over determined using mathematical analysis. To come up with the realistic attitude determination a number of determinant influencers need to be considered. Accuracy levels of the sensors need to be maintained by minimizing errors and ensuring correct positioning are maintained. A realistic error and noise models are calculated and mitigated. An astrologists need better algorithms are employed to estimate the direction of the sensors towards the body frame of the satellite component in order to come up with appropriate rotational matrix. Because use of sensors (sun and earth) is new developments more projects and experiments need to be done to enable astrologists be able to accurately determine the attitude of satellites and other space craft bodies. References lists Chang, Y.K., Yun, M.Y. and Lee, B.H., 2007. A new modeling and validation of two-axis miniature fine sun sensor. Sensors and Actuators A: Physical, 134(2), pp.357-365. Daz-Michelena, M., 2009. Small magnetic sensors for space applications. Sensors, 9(4), pp.2271-2288 Furgale, P., Enright, J. and Barfoot, T., 2011. Sun sensor navigation for planetary rovers: Theory and field testing. IEEE Transactions on Aerospace and Electronic Systems, 47(3), pp.1631-1647. 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