Simulation-based evaluations of HF radar ocean current algorithms

Laws, K.; Fernandez, D.M.; Paduan, Jeffrey D.

doi:10.1109/48.895355

Cited by 56 publications

(24 citation statements)

References 9 publications

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“…4, where SNR= 20 dB. It is challenging to characterize the jet feature of the current profile because the Gaussian-shaped feature can contain regions of several DOAs depending on the maximum amplitude and σ G 2 (Laws et al 2000). The results show that the jet feature has been approximately retrieved by SS-MUSIC, CVSR-MUSIC, and RVSR-MUSIC.…”

Section: Simulation Resultsmentioning

confidence: 67%

Remote sensing of surface currents with single shipborne high-frequency surface wave radar

Wang

Xie

et al. 2015

Ocean Dynamics

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High-frequency surface wave radar (HFSWR) is a useful technology for remote sensing of surface currents. It usually requires two (or more) stations spaced apart to create a twodimensional (2D) current vector field. However, this method can only obtain the measurements within the overlapping coverage, which wastes most of the data from only one radar observation. Furthermore, it increases observation's costs significantly. To reduce the number of required radars and increase the ocean area that can be measured, this paper proposes an economical methodology for remote sensing of the 2D surface current vector field using single shipborne HFSWR. The methodology contains two parts: (1) a real space-time multiple signal classification (MUSIC) based on sparse representation and unitary transformation techniques is developed for measuring the radial currents from the spreading first-order spectra, and (2) the stream function method is introduced to obtain the 2D surface current vector field. Some important conclusions are drawn, and simulations are included to validate the correctness of them.

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Section: Simulation Resultsmentioning

confidence: 67%

Remote sensing of surface currents with single shipborne high-frequency surface wave radar

Wang

Xie

et al. 2015

Ocean Dynamics

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“…2. The dimension of the sea patch is 0.5 • by 500 m [11], which can be considered small in comparison with the 180 • by 5 km section of ocean surface being processed for a given range bin in real radar system. Reflections from patches in the same range bin are summed to find the total sea echo signal.…”

Section: A Radar System and Sea State Parametersmentioning

confidence: 99%

“…When the radar system is installed on a platform, its motion may lead to additional Doppler frequency shift of the Bragg peaks, and the amplitude of the shift is related to the azimuth of the sea patch. Thus the echo signal from a given sea patch can be expressed as the sum of two exponentials (9) where A ± denotes the amplitude of the sea echo due to Bragg scatter, which can be expressed as Gaussian random variables with variance proportional to the ocean wave spectral energy at the Bragg frequency [11]. f B is the Bragg frequency and f c (θ s ) is the radial component of Doppler frequency shift caused by ocean currents at the direction θ s .…”

Section: B Received Signal Modelmentioning

confidence: 99%

“…When the platform moves faster and the array aperture is short, however, this radial current measurement method may have drawbacks due to the limited azimuth resolution of those direction-finding algorithms. MUltiple SIgnal Classification (MUSIC) has been widely used to detect target or measure ocean surface current in many onshore HFSWRs [10], [11]. In our previous works [12], [13], MUSIC has also been tentatively applied in shipborne HFSWR, however, the six-DOF motion of the platform is not considered.…”

Section: Introductionmentioning

confidence: 98%

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Ocean Surface Current Measurement Using Shipborne HF Radar: Model and Analysis

Chang

Xie

et al. 2016

IEEE J. Oceanic Eng.

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The extension of onshore high-frequency surface wave radar (HFSWR) to shipborne HFSWR has the advantage of extended monitoring area and high application flexibility. However, additional modulation on the echo signal introduced by the forward movement and six-degree-of-freedom (6-DOF) ship motion may increase the surface current measurement error. Considering the radar array position on the ship, six-DOF ship motion, forward movement velocity, first-order Bragg scatter, and background noise, this paper models the backscattered Doppler spectrum of shipborne HFSWR. Based on this model, the performance of surface radial current measurement is analyzed, with the adoption of the MUltiple SIgnal Classification (MUSIC) to estimate the azimuth of the sea patches. Simulation results show that, rotation, sway and forward movement of the ship all have significant impacts on the surface radial current measure error. Nevertheless, if the ship sails at relative low speed and keeps its sailing direction (with small yaw amplitude), shipborne HFSWR may provide a better result than onshore HFSWR.Index Terms-Multiple signal classification, ocean surface current, shipborne high-frequency surface wave radar (HFSWR).

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“…However, accurately determining the DOA of current signals and assessing the estimation performance are much more complex. Studies focused on current measurements with different HF radar systems have been previously performed by researchers all over the world in the past several decades, and a number of studies have evaluated the MUltiple SIgnal Characterization (MUSIC) algorithm or antenna pattern for direction-finding HF radar [14,15]. Many studies comparing HF radar current measurements with in situ current measurements have been developed by researchers interested in radar performance [16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Validation of Sensing Ocean Surface Currents Using Multi-Frequency HF Radar Based on a Circular Receiving Array

Zhao

Chen

et al. 2018

Remote Sensing

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Abstract:To reduce the floor space of receiving antenna arrays, the Radio Ocean Remote SEnsing (RORSE) laboratory of Wuhan University developed a circular receiving array for a multi-frequency high frequency (MHF) radar system in 2014, consisting of seven uniformly spaced antenna elements positioned on a circle with a diameter of 5 m. The new system, which is abbreviated MHF-C radar, adopts frequency modulated interrupted continuous wave (FMICW) chirps and is capable of simultaneously operating at a maximum of four frequencies in the band of 7.5-25 MHz, and providing current, wave and wind maps every ten minutes. The phase direction-finding method is utilized to estimate the directions of the current signals, and array phase uncertainties are also taken into consideration in the signal model. This paper introduces the system in detail and investigates the performance of current measurements using MHF-C radars installed at Shengshan and Zhujiajian along the coast of the East China Sea. Radial current measurements derived from 8.27 MHz and 19.20 MHz at the same range are compared. Observations and comparisons between MHF-C radars and acoustic Doppler current profilers (ADCPs) are also presented in this paper. The results preliminarily demonstrate that the MHF-C radar system is capable of maintaining the same performance for current measurements whenever it steers to any other azimuth in the coverage and has a good ability to measure currents.

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Simulation-based evaluations of HF radar ocean current algorithms

Cited by 56 publications

References 9 publications

Remote sensing of surface currents with single shipborne high-frequency surface wave radar

Remote sensing of surface currents with single shipborne high-frequency surface wave radar

Ocean Surface Current Measurement Using Shipborne HF Radar: Model and Analysis

Validation of Sensing Ocean Surface Currents Using Multi-Frequency HF Radar Based on a Circular Receiving Array

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