Results 21 to 30 of about 188 (137)

Over-the-horizon aircraft detection using skywave AM-radio broadcast signals [PDF]

open access: yes, 2015
We present the preliminary experimental results of a collaborative research project to determine the feasibility of using AM-radio broadcasts of opportunity for aircraft detection at ranges of thousands of kilometers from a terrestrial receiver.
Ng, B.   +4 more
core   +1 more source

Spread Sea Clutter Suppression in HF Hybrid Sky‐Surface Wave Radars Based on General Parameterized Time‐Frequency Analysis

open access: yesInternational Journal of Antennas and Propagation, Volume 2020, Issue 1, 2020., 2020
In high‐frequency (HF) hybrid sky‐surface wave radar, the first‐order sea clutter broadening is severe under the action of ionospheric phase disturbance and bistatic angles. In this paper, a cascaded method is described to suppress the spread sea clutter.
Zhuo-qun Wang   +7 more
wiley   +1 more source

High frequency surface wave radar (HFSWR) simulator [PDF]

open access: yes, 2007
110 p.High Frequency (HF) - Radar ,also known as Over-The-Horizon (OTH) Radar is able to detect targets that are over the horizon up to a few hundreds kilometers, beyond the range of a conventional radar.
Teo, Mia Koon
core   +1 more source

Tracking Water Dynamics of a Temperate Forest Under Drought and Non‐Drought Conditions Using Active and Passive Microwave and Optical Remote Sensing

open access: yesJournal of Geophysical Research: Biogeosciences, Volume 131, Issue 5, May 2026.
Abstract Water status, water dynamics, and ecohydrological resilience of a protected German beech forest during the 2018–2020 multi‐year drought are assessed using over six years of multi‐frequency remote sensing data, integrating active, passive, and optical sensors with varying canopy penetration depths, highlighting the importance of monitoring ...
Florian M. Hellwig   +10 more
wiley   +1 more source

Multiscale Assessment of the Water Balance Components in Arizona Simulated by the National Water Model

open access: yesJAWRA Journal of the American Water Resources Association, Volume 62, Issue 1, February 2026.
ABSTRACT Arizona, located in the Desert Southwest of the U.S., faces chronic water scarcity and has been strongly affected by the multidecadal Millennium Drought. As the state increasingly turns to water augmentation strategies, accurate, high‐resolution estimates of water balance components are essenctial.
Abdul Moiz, Giuseppe Mascaro
wiley   +1 more source

The First Results of Ionospheric Skywave Propagation Experiment Over Taiwan

open access: yesRadio Science, Volume 61, Issue 1, January 2026.
Abstract An ionospheric over‐the‐horizon propagation experiment was carried out in Taiwan to investigate characteristics of ionospheric F layer skywave propagation at frequencies 4–12 MHz. Experimental results show that there are prominent diurnal variations in the incident angle, virtual height and plasma frequency at reflection height, which are ...
Hung‐Shi Lin   +3 more
wiley   +1 more source

Signal Processing Methods to Improve Ocean Surface Wave Estimation from a High Frequency Surface Wave Radar [PDF]

open access: yes, 2011
High frequency surface wave radars are operated as a remote sensor to measure ocean surface parameters to ranges exceeding 200-300 km from the coastline.
Wang, Wei
core  

Time Synchronisation for Passive Bistatic HFSWR via Kalman‐Filtered Delay‐Locked Loop

open access: yesIET Radar, Sonar &Navigation, Volume 20, Issue 1, January/December 2026.
This paper proposes a per‐chirp time synchronisation method, FLOS‐Kalman‐DLL, for passive bistatic high‐frequency surface wave radar (HFSWR) operating under the coexistence of clock drift and atmospheric impulsive noise. The method combines fractional lower‐order statistics with a Kalman‐filtered delay‐locked loop to achieve sub‐sample synchronisation ...
Yuan Lu, Jie Song, Wei Xiong, Yaqi Cui
wiley   +1 more source

HF radar signatures of ship and submarine wakes

open access: yesThe Journal of Engineering, Volume 2019, Issue 21, Page 7512-7520, November 2019., 2019
Radars operating in the HF band have been widely used to detect and track surface ships from their skin echoes; indeed, in many cases this has been the primary mission of the radar. Yet vessels moving on and through the ocean create a family of disturbances collectively referred to as the wake, though a number of different mechanisms and phenomena are ...
Stuart J. Anderson
wiley   +1 more source

Ambiguity and area preserving linear transformations in over‐the‐horizon radar

open access: yesIET Radar, Sonar &Navigation, Volume 19, Issue 1, January/December 2025.
The use of recurrent waveforms in over‐the‐horizon radar (OTHR) necessitates techniques for ambiguity resolution and manipulation. In this paper, the authors elucidate methods for systematically transforming any given waveform so that its ambiguity function is transformed by any desired area preserving the linear transformation of the delay‐Doppler ...
Stephen D. Howard, Van Khanh Nguyen
wiley   +1 more source

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