As early as 1904, Christian Hülsmeyer patented the first RADAR, called an obstacle detector and ship navigation device. It was based on experiments by Heinrich Hertz in 1888 in which the polarisation dependent reflection of electromagnetic waves was detected. The theory had, of course, been produced even earlier, by James Clerk Maxwell. Although, it was only in 1935 that the first practical RADAR system was created by Robert Watson-Watt. However, in the last two decades RADAR technology has not advanced like that of communications. Until now! A combination of the innovations of high-speed electronic devices and heightened demand have created a climate for revolution.
RADAR of the past
James Maxwell’s work on the general equations of the electromagnetic field, determined that light and radio waves are both examples of electromagnetic waves, and are each governed by the same laws, but with very different frequencies. Heinrich Hertz proved Maxwell’s theory by using radio waves at a wavelength of 66cm; a frequency of approximately 455MHz.
Unfortunately, as is often the case, it was war that accelerated RADAR innovation in its early years. In the 1930s, long-range military bombers were invented, providing a need to detect hostile aircraft upon approach. The first RADAR systems developed by the US Army were the SCR-268, with a frequency of 205MHz, and the SCR-270, with a frequency of 100MHz. The former was used for controlling anti-aircraft gunfire, while the latter was designed to detect incoming aircraft. Regardless, perhaps unsurprisingly, considering Hertz was a German physicist, by the start of World War II, Germany had the most effective perimeter RADAR technology.
RADAR of the present
By comparison, some of the latest perimeter RADAR technology utilises state-of-the-art Mimo and digital beam-forming technology to cover an area of more than 500000 metres squared, with a detection range of up to 1000m for vehicles and boats, for instance, and up to 250m for drones. Demanding very little power, at less than 5 Watts, its accuracy is extraordinary, even in awkward environments.
The latest uses for RADAR include tracking illegal shipping activity, with a RADAR satellite recently launched by the UK. It can take pictures of the Earth’s surface in any weather and at any time. Such advancements are critical for our security in an ever more dangerous world. From a facility requiring high-tech surveillance, to the entire planet, RADAR technology is indispensable for modern perimeter security.