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We have conducted the basic research on long horizontal communication using time reversal in the deep ocean, which will be applied for communicating with an autonomous underwater vehicle (AUV) in the future. To achieve such communication, time reversal is an attractive solution. Because intersymbol interferences (ISI) are removed and signal noise ratio is improved. In our previous studies, a method...
In this paper, a basic study on acoustic navigation for long range cruising AUV is described. Typically the position of AUV can be estimated by measuring the range between the AUV and acoustic sources or bearing of the acoustic signal. In long range observation, it is difficult to estimate these parameters in three dimensional. Depth can be directly sensed by depth sensor, then we can estimate the...
Collinear holographic memory is one of the candidates of post Blu-ray disc system. This system has several advantages comparing to other holographic memory systems. For examples, collinear system is quite stable because both reference and signal waves passes through common optical elements. In this paper, we will present the estimation of these noises with our model for the collinear holographic memory...
Single page SNR is obtained with the page data read and write simulation based on the model we proposed before. Shift selectivity is calculated with the simple Fourier transformation of the reference pixel pattern. Several numerical results are shown and both two factors strongly depend on the reference pattern. Experimental verification of our calculation of the shift selectivity is also presented.
In recent years, precious observations by autonomous underwater vehicle (AUV) have been performed. Tracking and navigation of AUV are important for precious observations. In Japan agency for Marine-earth Science and Technology (JAMSTEC) the observations with AUV ldquoURASHIMArdquo have been implemented in deep ocean area. AUV URASHIMA is navigated by an inertial navigation system (INS) mainly. The...
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