Papers by Khachatur Tovmasyan
Using QAM mapped OFDM signal in radar applications it is possible to get from the signal constell... more Using QAM mapped OFDM signal in radar applications it is possible to get from the signal constellations both the target velocity and target distance from the radar station. When in the reflected signal constellation we get the rotated and distorted mapping that is mean that the signal is reflected from the moving target, while on the other hand, when the mapping is only rotated around the zero, we have a reflected signal from static target. Getting that signals and passing them through frequency and target distance filter banks we get the Doppler frequency and time shift and, consequently, the velocity and the distance of the target.
Algorithm of clutter reduction in LFM CW radars is presented. Similarities in sequential measurem... more Algorithm of clutter reduction in LFM CW radars is presented. Similarities in sequential measurements are formalized via introduced identification function. Ensemble averaging allows significantly simplify moving target identification.
Doppler effect gives a frequency offset on received OFDM signal in radar system. That offset can ... more Doppler effect gives a frequency offset on received OFDM signal in radar system. That offset can be seen as a distortion and rotation of reflected signals QPSK mapping vectors. It is possible to determine moving target velocity by estimating expected value of the distorted signal and then calculating the rotated angle. A mathematical relationship between Doppler frequency shift and rotated angle of QPSK mapping vectors was obtained. The recommended systems will require less computing resources, because Doppler frequency shift calculation could be done during one OFDM symbol.
QAM mapped OFDM signal processing gives an opportunity to solve two of the main tasks of radar ap... more QAM mapped OFDM signal processing gives an opportunity to solve two of the main tasks of radar applications, i.e., target velocity and target range. Reviewing reflected signal constellation we can see the rotated and distorted mapping, which occurs as a result of the moving target. On the other hand when the mapping is only rotated around the zero, we have a reflected signal from a static target. After passing this signal through the frequency and target range filter banks we can easily get the Doppler frequency and time shift and consequently the velocity and the target range.
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Papers by Khachatur Tovmasyan