The Algorithm of VLBI Wide-Band Correlation and CE-2 Broadband Signal Processing

In this paper, firstly, we discuss the specific processing algorithm of wide-band VLBI signal，which can be used in astronomy and geodesy. We focus on the theory, algorithm, result and by simulation we verified it. When the Chang’E Ⅱ on its orbit, we organize a short baseline interferometer experiment and get correlation fringe successfully, meanwhile, we compare the result with the data of precise theoretical orbit. It proves that the system is successful, and the algorithm is useful and correct.

New broadband methods for resonance classification and high-resolution imagery of fish with swimbladders using a modified commercial broadband echosounder

Stanton, T. K., Chu, D., Jech, J. M., and Irish, J. D. 2010. New broadband methods for resonance classification and high-resolution imagery of fish with swimbladders using a modified commercial broadband echosounder. – ICES Journal of Marine Science, 67: 365–378. A commercial acoustic system, originally designed for seafloor applications, has been adapted for studying fish with swimbladders. The towed system contains broadband acoustic channels collectively spanning the frequency range 1.7–100 kHz, with some gaps. Using a pulse-compression technique, the range resolution of the echoes is ∼20 and 3 cm in the lower and upper ranges of the frequencies, respectively, allowing high-resolution imaging of patches and resolving fish near the seafloor. Measuring the swimbladder resonance at the lower frequencies eliminates major ambiguities normally associated with the interpretation of fish echo data: (i) the resonance frequency can be used to estimate the volume of the swimbladder (inferring the size of fish), and (ii) signals at the lower frequencies do not depend strongly on the orientation of the fish. At-sea studies of Atlantic herring demonstrate the potential for routine measurements of fish size and density, with significant improvements in accuracy over traditional high-frequency narrowband echosounders. The system also detected patches of scatterers, presumably zooplankton, at the higher frequencies. New techniques for quantitative use of broadband systems are presented, including broadband calibration and relating target strength and volume-scattering strength to quantities associated with broadband signal processing.