Direction finding with tdoa in a multipath land environment

Başçiftçi, Çağrı Halis
In this thesis, the problem of Angle of Arrival estimation of radar signals with Time Difference of Arrival method in an outdoor land multipath environment with limited line of sight is analyzed. A system model is proposed. Effects of system, channel and radar parameters on the Angle of Arrival estimation performance are investigated through Monte Carlo simulations. Improving effect of utilization of diversity on the estimation performance is observed. Performances of the space diversity with noncoherent and selective combining are compared. Finally a realistic scenario is studied and performance of the proposed system is investigated.


Range resolution improvement of fmcw radars
Kurt, Sinan; Demir, Şimşek; Department of Electrical and Electronics Engineering (2007)
Frequency Modulated Continuous Wave (FMCW) radar has wide application areas in both civil and military use. The range resolution is a critical concept for these FMCW radars as for the other radar types. There are theoretical restrictions in the range resolution. In addition, the non-ideal properties of the modules used in the systems negatively affects the range resolution. The transmitter leakage, non-linear frequency sweep, FM to AM distortion and measurement errors are some of the critical non-ideal prop...
Frame synchronization in OFDM systems
Gürsan, Hakan Yesari; Tuncer, Temel Engin; Department of Electrical and Electronics Engineering (2005)
In this thesis, we considered the problem of frame synchronization and channel estimation in Orthogonal Frequency Division Multiplexing (OFDM) systems. Since framing error may cause severe ISI and may disturb the orthogonality of the subcarriers, frame synchronization must be accomplished at the OFDM receiver. Furthermore, the effects of channel must be compensated to obtain the symbols accurately. We investigated several frame synchronization algorithms including a maximum likelihood (ML) synchronizer whic...
Comparison of the intercarrier interference cancellation methods in OFDM systems
Etiler, Burkay; Tuncer, Temel Engin; Department of Electrical and Electronics Engineering (2007)
In OFDM systems carrier frequency offset is observed due to Doppler shift and transmitter-receiver frequency mismatches. This offset induces ICI (Intercarrier Interference). In this thesis, repeated data methods and pilot-aided carrier frequency offset(CFO) estimation methods and windowing techniques are used to mitigate the frequency offset problem and a performance comparison is made between these ICI cancellation techniques. Repeated data methods use only half of the bandwidth for information transmissio...
Radar range-doppler imaging using joint time-frequency techniques
Akhanlı, Deniz; Dural Ünver, Mevlüde Gülbin; Department of Electrical and Electronics Engineering (2007)
Inverse Synthetic Aperture Radar coherently processes the return signal from the target in order to construct the image of the target. The conventional methodology used for obtaining the image is the Fourier transform which is not capable of suppressing the Doppler change in the return signal. As a result, Range-Doppler image is degraded. A proper time-frequency transform suppresses the degradation due to time varying Doppler shift. In this thesis, high resolution joint-time frequency transformations that c...
Analysis and design of a circularly polarized microstrip antenna
Taştan, Mehmet; Koç, Seyit Sencer; Department of Electrical and Electronics Engineering (2006)
In this study we tried to design a microstrip antenna, to get a suitable radiation pattern for a LEO satellite. Our aim is to get a radiation pattern that has a maximum power which is not in the broadside direction to the antenna surface; instead broadside radiation has a relatively lower power density. Maximum power radiation is desired to be at about 30 50 degrees angle beyond the normal to the antenna surface. We desire circularly polarized radiation. We used two concentric antennas; one is a circular p...
Citation Formats
Ç. H. Başçiftçi, “Direction finding with tdoa in a multipath land environment,” M.S. - Master of Science, Middle East Technical University, 2007.