Javad Salem; hossein pilaram; seyyed mohammad alavi
Volume 9, Issue 4 , April 2017, , Pages 51-63
Abstract
For the detection of and tracking thelow earth orbit Satellites (LEO), there are different methods such as optic, laser and radar tracking, among which radar tracking is the best. Since the common linear tracking filters deployed in available radars are not able to estimate the position of the non-linear ...
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For the detection of and tracking thelow earth orbit Satellites (LEO), there are different methods such as optic, laser and radar tracking, among which radar tracking is the best. Since the common linear tracking filters deployed in available radars are not able to estimate the position of the non-linear dynamic satellites, it is advisable to use non-linear filters. In this paper, firstly, the satellite motion path around the earth as well as radar observations are produced by the STK software. Accordingly, the samples are fed to non-linear Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF). Finally, the performance of the aforementioned filters is studied through evaluation of RMS position and estimation errors. Simulation results demonstrate that the Unscented Kalman filter has a better performance in terms of accuracy with respect to the Extended Kalman filter. In addition, using this method, theerror of observations decreases 50% along the range and 70% along the azimuth and elevation.
Tahereh Broomandnezhad; Mohammad Abdollahi Azgomi; Shahrokh Jalilian
Volume 5, Issue 4 , January 2013, , Pages 9-18
Abstract
Satellite software is a kind of application that are exposed to soft-errors or transient faults because they work in an environment, which is full of radiations. This kind of fault has caused error in the execution of software. Satellite designers have used different methods, such as hardware shielding ...
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Satellite software is a kind of application that are exposed to soft-errors or transient faults because they work in an environment, which is full of radiations. This kind of fault has caused error in the execution of software. Satellite designers have used different methods, such as hardware shielding and component hardening, for removing the effects of this type of errors. These methods will increase the cost, weight and power consumption. Also, thesemethods decrease the performance. Recently, researches have shown that instead of spatial components,, COTS components can be used in LEO satellites. In addition, software implemented hardware fault tolerance (SIHFT) techniques can be added to these components for dealing with transient faults. In this paper, a branch of these techniques, which is called control flow based techniques, are investigated and the useful method among them is highlighted. The result of the implementation, testing and evaluation of the selected method (i.e. RSCFC) is also presented in this paper.
