Koker, Abdulkadir
Tekinaip, Ozan
In this paper, an orbit determination strategy that uses non-recursive batch filter, and unscented Kalman filter methods is presented and utilized for satellite orbit determination. For the orbit determination system, the range, azimuth, and elevation angles of the satellite measured from ground tracking stations are used for observations. An efficient filter initialization algorithm using the Gibbs method is also proposed to provide an initial state estimate. The non-recursive batch filter is applied to improve initial conditions and to provide initial covariance. Finally, the unscented Kalman filter is used for recursive nonlinear estimation of the states of an Earth-orbiting satellite. The effect of measurement noise and observation duration on orbit determination accuracy is also investigated, and presented.


Orbit determination strategy and verification for geosynchronous satellites
Köker, Abdulkadir; Tekinalp, Ozan; Department of Aerospace Engineering (2019)
In this thesis, the batch and sequential orbit determination procedures for the geostationary satellites are presented. The aim of the study is to investigate the effect of the angle only and standard angle-range measurements on orbit determination accuracy. The effect of various factors on estimation accuracy such as measurement frequency, observation duration, and number of observation sites are investigated using the simulated measurement data. Estimation methods namely, nonlinear least square, extended ...
Orbital and spin phase-resolved spectroscopy of the intermediate polar EX Hya using XMM-Newton data
Pekon, Y.; Balman, Şölen (Oxford University Press (OUP), 2011-02-01)
We present the orbital phase-resolved spectra of an intermediate polar, EX Hya, together with the spin phase-resolved spectra during two different epochs using the X-ray Multi-Mirror Mission (XMM-Newton), European Photon Imaging Camera (pn instrument). We find that the source at the two epochs has the same X-ray luminosity of similar to 6.5 x 1031 erg s-1. We detect spectral variations between the 2000 and 2003 observations of the source. We fitted the spectrum using a neutral hydrogen absorption model with...
GPS-Based Real-Time Orbit Determination of Low Earth Orbit Satellites Using Robust Unscented Kalman Filter
Karslıoğlu, Mahmut Onur; Erdogan, Eren; Pamuk, Onur (2017-11-01)
In this research, a novel algorithm for real-time orbit determination (RTOD) is presented using the robust unscented Kalman filter (RUKF) with global positioning system (GPS) group and phase ionospheric correction (GRAPHIC) observables. To increase the reliability of the solution, a robust approach is included in the UKF to cope with the bad, invalid, or degraded measurements leading to the divergence or inaccurate output of the filter. Robustness is provided by making the filter less sensitive to faulty me...
CMOS LNA design for LEO space S-Band applications
Telli, A; Askar, M (2003-05-07)
In this study, LNAs for low earth orbit (LEO) S-Band uplink/downlink "System-on-Chip" receiver stages with different topologies are designed and simulated using the Mietec CMOS 0.7mum process and the Cadence/BSIM3v3 tool.
Radar cross section analysis by shooting and bouncing rays method
Çakır, Mustafa Kağan; Tokdemir, Turgut; Department of Engineering Sciences (2015)
In this study, a MATLAB code incorporating `Shooting and Bouncing Rays (SBR) Method` is developed for calculating Radar Cross Section (RCS) of complex shapes. The code can calculate ray paths, magnetic current sheets, incident and scattered electric fields and RCS in horizontal, vertical and cross polarizations. While reflection effects are calculated by SBR algorithm, diffraction effects due to edges and corners are handled by `Equivalent Edge Currents (EEC’s)`. Wave frequency, aspect angle and number of r...
Citation Formats
A. Koker and O. Tekinaip, “ORBIT ESTIMATION STRATEGY FOR LOW EARTH ORBIT AND GEOSTATIONARY SATELLITES,” 2019, vol. 167, p. 2859, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/65713.