Validation of Tsunameter in laboratory environment

1842-1847In this work authors reports simulation of tsunami detection algorithm in MATLAB software, validation of tsunami detection system in a tank, qualification of tsunami detection algorithm in an automated test rig in the laboratory. It also discuss the results from tsunami detection systems on a tsunami event (12 September 2007) deployed in the Bay of Bengal

Techniques adopted in the post processing of active sonar data from Royapuram site-off Chennai

164-171<span style="font-size:9.0pt;font-family: " times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";mso-ansi-language:="" en-gb;mso-fareast-language:en-us;mso-bidi-language:hi"="" lang="EN-GB">A buried object detection SONAR has been developed by the marine sensors and systems group of National Institute of Ocean Technology and the analysis of the data from a specific site is reported in the paper.  Handling the unpredictable noise is a major concern in sonar signal processing, especially in buried object detection sonar systems. To improve the signal to noise ratio and also to preserve the boundaries of targets, special post processing techniques are to be applied. Signal averaging is found to be a useful technique in this regard and this paper compares and analyzes various averaging techniques including moving averaging, exponential averaging, and median filter. The exponential averaging with median filter is found to be one of the best suitable methods for noise reduction in detecting buried objects in shallow waters, since it significantly improves the signal to noise ratio by preserving the boundaries of targets. It is observed that the original sonar image with 6% noise level is improved to 0.03 to 0.04 noise variance using the combination of exponential moving average and median filter and the same trend is observed up to 35% noise level when corrupted by Gaussian noise. Performance evaluation of the techniques has been carried out and is quantitatively verified with the data collected during the sea trials.</span

Design and field validation of Lagrangian drifters with INSAT communication for oceanographic and meteorological applications.

323-327<span style="font-size:9.0pt;line-height: 115%;font-family:Calibri;mso-fareast-font-family:Calibri;mso-bidi-font-family: " times="" new="" roman";mso-ansi-language:en-us;mso-fareast-language:en-us;="" mso-bidi-language:ar-sa;mso-bidi-font-weight:bold"="" lang="EN-US">National Institute of Ocean Technology (NIOT) has successfully indigenously developed the Lagrangian drifter buoy which is built with geostationary based Indian satellite communication module for Meteorological/Oceanographic applications and it has been named Pradyu. The drifter buoy-Pradyu has been successfully interfaced with NTC type Sea Surface Temperature (SST) sensor, Smart GPS receiver, INSAT communication modem and designed with holy sock drogue acting as the sea anchor which was fabricated using nylon collapsible cordura material. Drifter buoy was indigenized following internationally accepted measurement scheme and data transmission protocol, which are mandatory on usage of data by international scientific community. This article consists of the design and field validation performed to evaluate in-house developed spherical Lagrangian drifter buoy.</span