DESIGN AND IMPLEMENTATION OF GROUND PENERATION RADAR SYSTEM USING CODED SEQUENCES AND IMPROVED TARGET DETECTION USING GOLAY CODES

摘要

Ground Penetration Radar (GPR) is one of the non-destructive and non-intrusive data collecting technologies used in geophysical measurements. A GPR system operating at carrier frequency 500 MHz and a bandwidth of 250 MHz was designed and developed. The major problem in most of the existing Ground Penetration Radar systems is masking of the weaker returns by the strong sidelobes. This problem 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 (PN), Barker or other maximal length sequences. We have tested the performance of Golay and PRBS sequences using 4096 and 8192 length sequences, respectively. When the correlation obtained using two M length Golay sequence is compared with one 2M length PRBS sequence, sidelobe level for Golay sequence is almost eliminated. This results in better performance to detect weaker returns. However, this claim may not hold true at low SNR's. We have shown the results in anechoic chamber. Our tests indicate that Golay sequence has lower sidelobe level than PN sequences.