Applications of high‐frequency radar

Headrick, J. M.; Thomason, J. F.

doi:10.1029/98rs01013

Cited by 82 publications

(53 citation statements)

References 13 publications

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“…The change of direction clearly appears from the behavior of the quaternions: in the first data collection (clockwise) the peaks of the blue line are in advance with respect to the cyan peaks, while it is the opposite in the initial phase of the second data collection where the platform was rotating in counterclockwise direction. Quaternions are useful to represent the attitude of a rotating body and are easily connected to the Euler angles as shown in (4). Hence from the quaternions, output of the navigation board, the Euler angles are computed.…”

Section: Navigation Resultsmentioning

confidence: 99%

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Low-Cost Mini Radar: Design Prototyping and Tests

et al. 2017

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Radar systems are largely employed for surveillance of wide and remote areas; the recent advent of drones gives the opportunity to exploit radar sensors on board of unmanned aerial platforms. Nevertheless, whereas drone radars are currently available for military applications, their employment in the civilian domain is still limited. The present research focuses on design, prototyping, and testing of an agile, low-cost, mini radar system, to be carried on board of Remotely Piloted Aircraft (RPAs) or tethered aerostats. In particular, the paper faces the challenge to integrate the in-house developed radar sensor with a low-cost navigation board, which is used to estimate attitude and positioning data. In fact, a suitable synchronization between radar and navigation data is essential to properly reconstruct the radar picture whenever the platform is moving or the radar is scanning different azimuthal sectors. Preliminary results, relative to tests conducted in preoperational conditions, are provided and exploited to assert the suitable consistency of the obtained radar pictures. From the results, there is a high consistency between the radar images and the picture of the current environment emerges; finally, the comparison of radar images obtained in different scans shows the stability of the platform.

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Section: Navigation Resultsmentioning

confidence: 99%

“…(iv) High Frequency (HF) and Very High Frequency (VHF) radars provide a larger coverage, but at the cost of a lower resolution [4]. (v) Airborne radars are characterized by both a relatively large coverage and a high resolution, but their employment is limited by endurance and running costs [5].…”

Section: Introductionmentioning

confidence: 99%

Low-Cost Mini Radar: Design Prototyping and Tests

et al. 2017

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“…According to the previous analysis, it is obvious that the suppression of the transient interference and the noise is equivalent to the recovery of the low-rank matrix S from the received signal matrix R. It should be pointed out that the traditional matrix recovery has been applied usually by considering real-valued data [14][15][16][17][18][19][20]. However, the received signals are complex-valued data in our signal model (1). It is shown in [33] that the problem of matrix recovery for complex-valued data can be easily modified by arranging the real and imaginary parts of the data in both real-valued matrices and applying matrix recovery to these matrices.…”

Section: Suppression Via Complex Matrix Recovery With Hankel Structurmentioning

confidence: 99%

Transient interference and noise suppression by complex matrix recovery with Hankel constraint

Shao-wei

2015

IET Radar, Sonar & Navigation

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The transient interference can dramatically degrade the performance of over-the-horizon radar. Traditional interference suppression methods need to detect the interferences, excise the corrupted data and reconstruct the data via interpolation. The detection is the precondition of the subsequent steps. In the cases where the interferences are weak, the traditional methods cannot efficiently detect and suppress them. In this study, the authors propose a novel interference suppression method based on matrix recovery. The proposed method formulates the interference suppression as a matrix recovery problem and solves the convex optimisation problem via the augmented Lagrange multiplier method. Unlike the traditional methods, the proposed method does not need the detection, excising and interpolation steps. The proposed algorithm can suppress not only the interferences including the weak and strong ones but also the noise. Experimental results have demonstrated the effectiveness of the proposed method.

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“…Skywave over-the-horizon radar (OTHR) can probe remote targets from the distance of 1000-3000 km by utilizing the ionospheric reflection of electromagnetic waves during the 3-30 MHz frequency band, which thus provides the capabilities of early-warning and strong anti-stealth characteristics [1,2]. However, due to the irregularity of ionospheric electron density, the received echoes have random disturbances and suffer from clutter Doppler spectrum broadening [3].…”

Section: Introductionmentioning

confidence: 99%

Mimo-Othr Waveform Optimization Based on the Mutual Information Theory

Luo¹,

Zhao

Luo³

2016

PIER M

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Abstract-In traditional over-the-horizon radar (OTHR), multipath propagation due to the multilayer ionospheric structure always deteriorates the detection performance. The properties of multipleinput multiple-output (MIMO) radar technique, which transmits wide beams with low gain at the transmitter and achieves receiver beam-forming to obtain narrow beams with high gain, make it an ideal choice for OTHR to detect target through multi-layer ionosphere and suppress strong clutter. This paper investigates the assumption of a two-layer ionospheric model and proposes a two-step MaxMin algorithm based on the mutual information theory to optimize MIMO-OTHR waveform so as to suppress clutter, interference and noise. The first step is to maximize the mutual information between the echo and target response from the same direction of arrival (DOA) in order to reduce the impact of noise. The second step is to minimize the mutual information between the echoes from different DOAs, in order to suppress the clutter and interference by reducing the correlation of the echoes from the different DOAs. Numerical experiments validate that this algorithm can improve range resolution and detection probability significantly. Experiment results also demonstrate that the previously harmful multipath propagation can be utilized to enhance the detection performance in MIMO-OTHR.

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Applications of high‐frequency radar

Cited by 82 publications

References 13 publications

Low-Cost Mini Radar: Design Prototyping and Tests

Low-Cost Mini Radar: Design Prototyping and Tests

Transient interference and noise suppression by complex matrix recovery with Hankel constraint

Mimo-Othr Waveform Optimization Based on the Mutual Information Theory

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