Ground Penetrating Radar (GPR) using electromagnetic pulse required high resolution due to its narrow bandwidth nature. The rising requirement for high resolution lead to specific demands for improved prediction methods, all requiring many aspects to be examined. In this paper, the application possibility of super resolution method MUSIC (Multiple Signal Classification) algorithm and FFT (Fast Fourier Transform) are examined. Combined Processing Method (CPM) of time domain response of MUSIC and IFFT (Inverse Fast Fourier Transform) is proposed for signal processing of GPR for the first time. Simulation and experimental results show that CPM has both high resolution and high receiving signal level than other conventional signal processing methods.

A pulse compression subsurface radar using a chirp signal has been developed and evaluated by experimental survey at an archaeological site. This subsurface radar shows the superior ability to detect buried objects by weaker transmitting power than that of a conventional subsurface radar. Although several types of subsurface radars are now used to probe buried objects, it is sometimes dif®cult to use them for archaeological surveys. This is because echoes from targets such as tombs, ruins, and old mounds are sometimes very weak owing to their smallness and electromagnetic properties, which are very similar to the surrounding soils. In contrast, a pulse compression radar using a chirp signal has the ability to detect a very weak signal masked by noise, with very high resolution. We have applied this technique to a subsurface radar for archaeological survey and assembled an experimental system of a chirp subsurface radar using a delay correlator for pulse compression. This system has been successfully tested at an archaeological site called`The remains of Tajiri' (Komochi, Gunma prefecture, Japan): a mounded tomb buried in the pumice layer has been clearly detected by this system.

We discuss the chiral symmetry breaking in general intersecting Dq/Dp brane models consisting of N c Dq-branes and a single Dp-brane with an s-dimensional intersection. There exists a QCD-like theory localized at the intersection and the Dq/Dp model gives a holographic description of it. The rotational symmetry of directions transverse to both of the Dq and Dp-branes can be identified with a chiral symmetry, which is non-Abelian for certain cases. The asymptotic distance between the Dq-branes and the Dp-brane corresponds to a quark mass. By studying the probe Dp-brane dynamics in a Dq-brane background in the near horizon and large N c limit we find that the chiral symmetry is spontaneously broken and there appear (pseudo-)Nambu-Goldstone bosons. We also discuss the models at finite temperature.

SUMMARYSubsurface radar to detect buried objects from the ground surface by using electromagnetic waves has been used widely for detection of buried pipes since a shallow subsurface zone of up to 2 to 3 m can be visualized with high resolution at high speed. On the other hand, deeper subsurface detection is required in searching for archaeological ruins. In this paper, a delay correlation-type subsurface radar using monocycle pulse signals modulated by M-sequence codes is proposed with a view to expanding the search range by increasing the average energy of the transmitted signals. With a test setup, a steel pipe buried 2.5 m below the ground surface was detected with a transmitting power of 1 mW. In regard to the maximum detectable range of the subsurface radar using this type of coded signals, this paper carries out a study from the point of view of both the time side-lobe and S/N. © 2001 Scripta Technica, Electron Comm Jpn Pt 1, 85(2): 816, 2002