"Sound Mirrors" also known as "Acoustic Mirrors" at Denge near Greatstone and Dungeness. This is a former RAF site where in the late twenties and early thirties, experimental buildings were built to provide early warning of aircraft reaching Britain. The "ears" were designed to capture sound.
You can only get close to the Sound Mirrors on a couple of days a year. When we visited, a Sony crew were filming some kind of promotional video.
South Africa is one of the a few countries in the world to have successfully developed a passive radar system, capable of detecting both large and small aircraft using only a signal receiver.
At last week’s Aardvark Roost Electronic Warfare Conference held outside Pretoria, Francois Maasdorp, an engineer at the Council for Scientific and Industrial Research (CSIR), told delegates that with passive radar one only needs a receiver to detect signals emitted by other sources, such as FM radio towers, TV transmitters, WiFi and weather radar.
This makes passive radar (also known as passive coherent location, passive bistatic radar, piggyback radar and covert radar) cost effective, highly mobile and covert. By using several antennas one can use triangulation to identify the location of an aircraft, or by using a single receiver one can use the angle of arrival of the signal to determine a target’s location.
Even when stealth technology was deadly secret and the F-117A did not officially exist, there was counter-stealth radar.
Textbooks told us radar cross-section (RCS) was frequency dependent, and tended to become increasingly so as the target shape grew more complicated. If the radar wavelength is of the same magnitude as prominent features of the target, the signal is scattered by a resonant mechanism that is unimpressed by cunning shaping or materials magic. In the 1980s, many older Russian systems operated in the VHF band, with wavelengths in the 1-2-meter range, which is about the same as the chord of a fighter’s tail surfaces and wingtips.
But, as I wrote in 1987:
“The price of increasing wavelength … is that the antenna has to grow in proportion to the wavelength in order to maintain a narrow beam and adequate resolution. The ‘mobile’ Soviet VHF radars are cumbersome, and early-warning radars such as Tall King (P-14) are large fixed structures and provide coverage of only one sector. Despite the size of their antennae, they are not accurate enough to manage a complete engagement.”
Industrial, civil and residential security solution providers are experiencing an increase in the demand for additional security techniques outside of the field of conventional technologies used for perimeter protection and wide area surveillance.
In recent weeks, Reutech Radar Systems (RRS), a Stellenbosch-based developer of radar and radar-based solutions, has launched a perimeter and wide area intrusion detection system. This system is designed to cater to increasing needs for persistent monitoring of perimeters or strategic areas for industrial and residential asset protection.
Concept of Reutech Radar Systems interlinked radar sensors
Traditional security installations often make use of a combination of physical barriers such as fences, CCTV cameras, fibre-optic sensors and microwave barriers, among others, to detect intrusion.
РЛС дальнего обнаружения системы предупреждения о ракетном нападении (СПРН) и контроля космического пространства высокой заводской готовности (ВЗГ).
77Я6 Воронеж — российская надгоризонтная радиолокационная станция системы дальнего обнаружения высокой заводской готовности. РЛС способна обнаруживать баллистические, космические и аэродинамические объекты, в том числе баллистические и крылатые ракеты.
В период до 1991 г. в СССР была создана и надежно функционировала уникальная система ракетно-космической обороны (РКО) страны в составе систем предупреждения о ракетном нападении (СПРН), контроля космического пространства (СККП), противокосмической обороны (ПКО) и противоракетной обороны (ПРО). Одним из основных элементов этих систем являются радиолокационные станции (РЛС) дальнего обнаружения, большинство из которых исчерпали свои расчетные технические ресурсы. Ныне действующие РЛС СПРН, СККП и ПКО были модернизированы и способны нормально функционировать достаточно длительное время.
