Brazilian technology company IACIT Soluções Tecnológicas S/A, which develops and produces air traffic control and management and maritime traffic control and management systems, weather radars, telemetry systems, and integrated networks (among other products and systems) for civil, public safety and defence purposes, displayed its new over-the-horizon (OTH) 0100 radar in public for the first time at the recent LAAD Defence & Security 2017 exhibition in Rio de Janeiro, in Brazil. A developmental model of the radar has been operating at the Albardão Lighthouse, in Brazil’s southernmost state of Rio Grande do Sul, since the end of last year. Its first results are currently being assessed.

OTH radars are not new, with the development of the technology having started in the 1950s, but only a few countries have developed and deployed such systems – the US, the then USSR (today, Russia), China, Australia, Canada and France – the UK was involved in joint research with the US. It seems that, hitherto, Australia has been the only southern hemisphere country to deploy such systems (designated Jindalee) – indeed, Australia is one of the world leaders in this technology. The great benefit of OTH radars is that, unlike conventional radars, they are not limited to detecting targets that are in the direct line of sight of the radar antenna. Their great drawback is that they are much less precise than conventional radars. They are thus more suitable for countries needing to monitor huge areas – such as Australia, Brazil, Canada, China, Russia and the US.

IACIT has developed the OTH 0100 in partnership with Israel Aerospace Industries and the Brazilian Navy. Currently, is has the ability to detect ships at a range of 200 nautical miles from the coast. This distance coincides with the internationally agreed limit for exclusive economic zones (EEZs). The company has not released any information about the system’s maximum range for detecting aircraft. However, the information it has released indicates that the system is optimised, or at least primarily or initially intended, for detecting surface targets.

The OTH 0100 allows the Brazilian Navy to detect and track any ships entering the country’s EEZ within the operational radius of the test and evaluation system at Albardão, even if they have their Automatic (vessel) Identification System transmitters switched off. Such ships are known as “noncooperative targets”. Exact identification of the vessel would require the despatch of a ship or, more usually, aircraft to intercept it.

The OTH 0100 is a high frequency (HF) system, its transmitter operating in the 3 MHz to 30 MHz frequency range, and simultaneously covers an arc of 120 º in azimuth. It has separate transmitting and receiving arrays, with the transmitter employing a pulse-Doppler waveform, the parameters of which are established by software. The receiver takes the form of a ring of vertical antennas, each connected to a highly sensitive digital receiver, which, in turn, sends the received signals to the central processing system.

“The circular antenna array ensures proper target detection and very high directivity, besides an additional unique efficiency in eliminating interference effects of ionospheric signals into the system,” states the company in its brochure. “IACIT OTH 0100 radar has digital processing architecture, added to sophisticated software with Digital Beam Forming, ([or better known as] DBF), processing, which allows the suppression of different interferences which occur in the HF frequency band, such as ionospheric interference, man-made noise and communication interference, providing better detection and tracking of targets.”