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- The INTIFANTE'00 sea trial: preliminary source localization and ocean tomography data analysisPublication . Jesus, S. M.; Coelho, E.; Onofre, J.; Picco, P.; Soares, C.; Lopes, C.The INTIFANTE'00 sea trial was a multidisciplinary experiment including testing of an autonomous surface vehicle, underwater communications, source localization and acoustic ocean tomography. The results shown here will concentrate on the source localization and ocean tomography data sets. The data gathered during a 24 hour run along a range independent track shows strong oceanographic features, possibly due to internal tide signature, both on the temperature data, as measured on the thermistor chain collocated with a vertical line array(VLA), and on the acoustic data. A range dependent track between 120 and 60 m water depth, shows a highly variable channel impulse response along time and range when the source was moving outwards from the VLA. In another acoustic track, the source was navigatated across a underwater canyon where the energy was rapidly distributed over a deep acoustic channel with sound trapped well below the thermocline. Good agreement between the modeled and measured channel responses represents the rst step towards matched- eld processinglike methods such as source localization and tracking and ocean tomography.
- AOB - Acoustic Oceanographic Buoy: concept and feasibilityPublication . Jesus, S. M.; Soares, C.; Silva, A.; Hermand, J.-P.; Coelho, E.The AOB - Acoustic Oceanographic Buoy is the single node of a network of “smart” buoys for acoustic surveillance, Rapid Environmental Assessment (REA) and underwater communications. The AOB is a lightweight surface buoy with a vertical array of acoustic receivers and temperature sensors to be air dropped or hand deployed from a small boat. The received data is geotime and GPS precisely marked, locally stored and processed by on board dedicated DSP hardware. AOBs can exchange data over a local area network that includes submerged, sea surface (like for instance other AOBs) and air or land located nodes, allowing for the integration of all users in a seamless network. Specific software allows AOB usage in complex tasks such as passive or multistatic acoustic surveillance, acoustic observations for REA oceanographic forecast and model calibration, bottom and water column acoustic inversion, underwater communications and cooperating target tracking. The AOB was successfully deployed in several consecutive days during two Maritime REA sea trials in 2003 (Mediterranean), in 2004 (Atlantic) and for an high-frequency underwater communications experiment during MakaiEX, 2005 (Hawai). Data collected at sea shows that the AOB is a versatile, robust and easy to use tool for a variety of broadband underwater acoustic applications.