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Analysis of Sidelobe Level Reduction Methods at Radar Matched Filter

Akbaripour, Amir Mokhtar | 2008

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 39245 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Bastani, Mohammad Hassan
  7. Abstract:
  8. Pulse compression techniques such as linear frequency modulation (LFM) and phase-coded pulse are an active research topic in radar systems, spread spectrum communication applications, etc. Pulse compression technique is employed to achieve high range resolution with enough low average power. A problem in pulse compression is masking of small targets by the range sidelobes of large nearby targets. Furthermore, the range sidelobes may be detected as separate targets and thus increase the false alarm. The most popular waveform among pulse compression techniques is the LFM (also known as chirp). However, the LFM waveform is susceptible to electronic warfare; hence using the biphase coded modulation is preferred over LFM in military applications. Moreover, the biphase coded pulse involves less implementation complexity. In this project, we study the pros and cons of common sidelobe level reduction methods in biphase coded pulse. Then, we propose a novel finite impulse response (FIR) filter structure which is applicable to all binary coded pulses. This structure can also be generalized to polyphase coded pulses. Next we present a modified infinite impulse response (IIR) filter that outperforms the existing IIR structures by decreasing the sidelobe levels substantially. Finally, in order to demonstrate the improvements achieved by the new structures, we compare the performance of our proposed filters with that of previous structures in terms of mainlobe to peak sidelobe level (MSR), loss of signal to noise ratio (SNR) and resistance to doppler effect.
  9. Keywords:
  10. Matched Filter ; Sidelobe level ; Pulse Compression ; Biphase Coding Signal

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