X-Band Radar for the Monitoring of Sea Waves and Currents: A Comparison between Medium and Short Radar Pulses

Abstract. This letter presents the monitoring results of the sea waves and the surface currents obtained by analyzing data acquired by a X-band marine radar in two different operative conditions, namely the short and medium pulse modes. In particular, we investigated the feasibility to use a medium radar pulse for sea state monitoring by comparing the performance in both the radar modes. The comparison was carried out by means of an experimental campaign and we observed a good agreement for surface current and sea state parameters estimation.

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Sea-State Monitoring Via X-Band Marine Radar Images Sequences: A New Approach for an Accurate Surface Currents Estimation

Volume 2: Structures, Safety and Reliability ◽

10.1115/omae2009-79748 ◽

2009 ◽

Author(s):

Francesco Serafino ◽

Claudio Lugni ◽

Francesco Soldovieri

Keyword(s):

Synthetic Data ◽

Surface Current ◽

Key Factors ◽

State Monitoring ◽

Sea State ◽

Reconstruction Procedure ◽

Factors Affecting ◽

Radar Images ◽

X Band ◽

Marine Radar

This work deals with the sea state monitoring starting from marine radar images collected on a moving ship. For such a topic, one of the key factors affecting the reliability of the reconstruction procedure is the determination of the equivalent surface current that also accounts for the speed of the moving ship. Here, we propose a method able to evaluate also high values of the sea surface current. The reliability of the proposed procedure is shown by a numerical analysis with synthetic data. Finally, we present some preliminary results with measurements collected on a moving ship.

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REMOCEAN: A Flexible X-Band Radar System for Sea-State Monitoring and Surface Current Estimation

IEEE Geoscience and Remote Sensing Letters ◽

10.1109/lgrs.2011.2182031 ◽

2012 ◽

Vol 9 (5) ◽

pp. 822-826 ◽

Cited By ~ 26

Author(s):

F. Serafino ◽

C. Lugni ◽

G. Ludeno ◽

D. Arturi ◽

M. Uttieri ◽

...

Keyword(s):

Surface Current ◽

Radar System ◽

State Monitoring ◽

Sea State ◽

Current Estimation ◽

X Band

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On the Reliability of Surface Current Measurements by X-band Marine Radar

Remote Sensing ◽

10.3390/rs11091030 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1030 ◽

Cited By ~ 4

Author(s):

Hessner ◽

El Naggar ◽

von Appen ◽

Strass

Keyword(s):

Real Time ◽

Surface Current ◽

Acoustic Doppler Current Profiler ◽

Weather Conditions ◽

Operational Reliability ◽

Current Data ◽

X Band ◽

Current Profiler ◽

Marine Radar ◽

Commercial Off The Shelf

Real-time quality-controlled surface current data derived from X-Band marine radar (MR) measurements were evaluated to estimate their operational reliability. The presented data were acquired by the standard commercial off-the-shelf MR-based sigma s6 WaMoS® II (WaMoS® II) deployed onboard the German Research vessel Polarstern. The measurement reliability is specified by an IQ value obtained by the WaMoS® II real-time quality control (rtQC). Data which pass the rtQC without objection are assumed to be reliable. For these data sets accuracy and correlation with corresponding vessel-mounted acoustic Doppler current profiler (ADCP) measurements are determined. To reduce potential misinterpretation due to short-term oceanic variability/turbulences, the evaluation of the WaMoS® II accuracy was carried out based on sliding means over 20 min of the reliable data only. The associated standard deviation σWaMoS = 0.02 m/s of the mean WaMoS® II measurements reflect a high precision of the measurement and the successful rtQC during different wave, current and weather conditions. The direct comparison of 7272 WaMoS® II/ADCP northward and eastward velocity data pairs yield a correlation of r ≥0.94, with bias∆ ≤0.06 m/s and σS=0.05 m/s. This confirms that the MR-based surface current measurements are accurate and reliable.

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Guard lines conformal slotted antenna array for multiband application

International Journal of Informatics and Communication Technology (IJ-ICT) ◽

10.11591/ijict.v10i2.pp140-147 ◽

2021 ◽

Vol 10 (2) ◽

pp. 140

Author(s):

Brajlata Chauhan ◽

Suresh Chandra Gupta ◽

Sandip Vijay

Keyword(s):

Antenna Array ◽

Impedance Matching ◽

Surface Current ◽

Wide Band ◽

Rectangular Slot ◽

Conformal Antenna ◽

Current Path ◽

Quarter Wavelength ◽

X Band ◽

Good Agreement

<span>This work investigated a miniaturized slotted conformal antenna array for multiband application. Three guard lines are incorporated to the side of main patch and top of main patch to reduce surface current for planner surface and observe the effect of guard line due to which it resonate at three frequencies in X band and Ku band to be useful for multiband. A rectangular slot is etched at center of patches to increase the current path for wide band application. A quarter wavelength feeding network is used with good agreement of impedance matching. The main lobe width and direction shows through the radiation pattern which remains stable even it is significantly curved. This structure is wrapped around a cylinder with a diameter of 41.4 mm in the circumferential direction. It is observed that the planner antenna array operating at 8.4 GHz, 11.2 GHz &18.2 GHz with a return loss of -20 dB to -45 dB with fractional BW of 25% at 3rd frequency range and the directivity from 3.4 dBi-6.8 dBi. By doing some alteration in dimensions for the conformal antenna producing fractional BW of 20% and the directivity 5.5 to 9.1 dBi at resonating frequencies of 8.4 GHz, 11.4 GHz, and 17.5 GHz. This proposed array is simulated on CST software.</span>

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Proof of Feasibility of the Sea State Monitoring from Data Collected in Medium Pulse Mode by a X-Band Wave Radar System

Remote Sensing ◽

10.3390/rs10030459 ◽

2018 ◽

Vol 10 (3) ◽

pp. 459 ◽

Cited By ~ 2

Author(s):

Giovanni Ludeno ◽

Francesco Raffa ◽

Francesco Soldovieri ◽

Francesco Serafino

Keyword(s):

Pulse Mode ◽

Radar System ◽

State Monitoring ◽

Sea State ◽

X Band ◽

Wave Radar

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Estimation of the Significant Wave Height from Marine Radar Images without External Reference

Journal of Marine Science and Engineering ◽

10.3390/jmse7120432 ◽

2019 ◽

Vol 7 (12) ◽

pp. 432 ◽

Cited By ~ 4

Author(s):

Ludeno ◽

Serafino

Keyword(s):

Wave Height ◽

Significant Wave Height ◽

State Monitoring ◽

Sea State ◽

Significant Wave ◽

Radar Images ◽

External Reference ◽

Challenging Tasks ◽

In Situ Sensors ◽

Marine Radar

In the context of the sea state monitoring by means of the X-band marine radar, the estimation of a significant wave height (Hs) is, currently, one of the most challenging tasks. For its estimation, a calibration is usually required using an external reference, such as in situ sensors, and mainly buoys. In this paper, a method that allows us to avoid the need for an external reference for Hs estimation is presented. This strategy is, mainly, based on the correlation between a raw radar image and the corresponding non-calibrated wave elevation image to which varying its amplitude by using a scale factor creates a mathematical model for the radar imaging. The proposed strategy has been validated by considering a simulated waves field, generated at varying sea state conditions. The results show a good estimation of the significant wave height, confirmed by a squared correlation coefficient greater than 0.70 for each considered sea state.

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Estimation of Sea Surface Current from X-Band Marine Radar Images by Cross-Spectrum Analysis

Remote Sensing ◽

10.3390/rs11091031 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1031 ◽

Cited By ~ 2

Author(s):

Zhongbiao Chen ◽

Biao Zhang ◽

Vladimir Kudryavtsev ◽

Yijun He ◽

Xiaoqing Chu

Keyword(s):

Current Velocity ◽

Wave Spectrum ◽

Surface Current ◽

Least Square ◽

Spectral Approach ◽

Spectral Correlation ◽

Radar Images ◽

X Band ◽

Marine Radar ◽

The Cross

The cross-spectral correlation approach has been used to estimate the wave spectrum from optical and radar images. This work aims to improve the cross-spectral approach to derive current velocity from the X-band marine radar image sequence, and evaluate the application conditions of the method. To reduce the dependency of gray levels on range and azimuth, radar images are preprocessed by the contrast-limited adaptive histogram equalization. Two-dimensional cross-spectral coherence and phase are derived from neighboring X-band marine radar images, and the phases with large coherences are used to estimate the phase velocity and angular frequency of waves, which are first fitted with the theoretical dispersion relation by different least square models, and then the current velocity can be determined. Compared with the current velocities measured by a current meter, the root-mean-square error, correlation coefficient, bias, and relative error are 0.15 m/s. 0.88, –0.05 m/s, and 7.79% for the north-south velocity, and 0.14 m/s, 0.86, 0.06 m/s, and 10.75% for the east-west velocity in the experimental area, respectively. The preprocessing, critical coherence, and the number of images for applying the cross-spectral approach, are discussed.

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