A Long Range Ground Wave Radar System For Off-shore Surveillance

Construction of sea surface current vectors using a single HF radar: A theoretical study

“… 6 For ground wave radar signals, which are transmitted at a horizontal angle, the detection of moving targets is based on the diffraction characteristics of HF electromagnetic waves propagating through the earth with a maximum detection distance of up to 400 km. 7 , 8 At the same time, ground wave radar can extract the wind field, wave field, current field, and other sea surface state information from the radar echoes using the first-order scattering and second-order scattering mechanism induced by the interaction between the ocean surface water and HF electromagnetic waves. In contrast, using the ionosphere as a reflector, skywave radar signals are projected onto the sea surface and then the sea surface scattering echo is reflected by the ionosphere again and received by the radar system with a maximum detection range of over 3,000 km based on the technology of HF ionospheric backscatter sounding.…”