The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper, we discuss the PAS (Pulse Active Sonar) and CAS (Continuous Active Sonar) strategies for target detection and tracking. CAS system potentially offer several advantages over traditional PAS systems, mainly in term of probability of detection and/or tracking. With a continuous insonification of the target, CAS can track continuously limiting the data association error inherent to PAS...
The use of orthogonal waveform can offer many advantages in covert underwater acoustic communication, including improved symbol detection ability. In this paper, we derive a new orthogonal code design. The proposed code has a good autocorrelation property compared to other codes. We present some results of a lake trial to evaluate the performance of the proposed method.
As a sonar transmitted waveform, binary phase-shift keyed (BPSK) signal has a nearly ideal ambiguity function. The good Doppler and time resolution properties make BPSK signal advantageous for underwater targets detection. Under the Doppler perturbation situation, the property of good Doppler resolution will result in a sharp decline in detection performance. In recent years, waveform fusion has got...
In practical underwater wireless optical communications (UWOC), pulse modulation technique has been widely used due to the high optical power efficiency and relatively low system complexity. Compared with the simplest on-off keying (OOK) scheme, digital pulse interval modulation (DPIM) improves both power efficiency and error performance and requires no symbol synchronization. Polarization shift keying...
In this paper, research was carried out to analyze the channel environment in the real sea using data measured in the shallow water of West sea of South Korea. By diversifying the distance between transmitter and receiver, we estimated RMS delay spread and maximum excess delay spread in various channel environments to draw coherence bandwidth and then estimated Doppler spread of received signal to...
The range resolution of an imaging sonar is difficult to be improved due to the restriction of the instantaneous bandwidth of the sonar system. To increase the range resolution of the imaging sonar, an imaging method with the use of the comb spectrum signal, which is composed of a set of continuous wave (CW) pulses with different center frequencies, is proposed. After the round-trip propagation these...
Precise understanding of the sea bottom characteristics and accurate identification of objects on the seabed are critical in many underwater applications. The severe multi-path along with the time varying and random reflections from the surface and the bottom of shallow waters, present an interesting and complex signal processing problem. A thin line hydrophone array, deployed from small Autonomous...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.