Low Sidelobe Level Radar Techniques Using Golay Based Coded Sequences

摘要

At present, widely-used Ground Penetration Radar (GPR) systems either use very short pulses or linear frequency modulated waveforms, and are based on either mono- or bi-static configurations. These systems suffer from having stronger sidelobes, thereby masking weaker returns from subtle changes and making it difficult to detect these changes. To overcome the problem of stronger sidelobes, various coding techniques have been proposed with varying degrees of success. The problem of embedded weaker returns in the stronger returns can be minimized to a great extent with the help of complementary Golay sequences. The performance of Golay sequences in terms of reduced sidelobe levels is considered better than that of pseudorandom binary sequences (PRBS), Barker or other maximal length sequences. A GPR system operating at 500 MHz with a bandwidth of 250 MHz is designed and developed at the New Mexico State University (NMSU). We have tested the performance of Golay and PRBS sequences using 4096 and 8192 length sequences, respectively. Our tests on roof-top of Thomas and Brown indicate that Golay sequence has lower sidelobe level than PRBS sequences. Different ranges of the targets where the experiment was performed were successfully determined. In this paper, we present some of our results.