Radar a.k.a Radio Detection and Ranging system detects radio waves coming from distant objects based on their characteristics like range, speed, shape, direction et al.
Clutter refers to noise technically ‘unwanted echoes’ based on topography i.e. land, sea, air, water, weather like rain, birds, insects, also point or discrete echoes from structures that produce large backscatter like buildings, TV, water towers, so on.
To make it ease, assume a ball thrown at wall coming back, likewise radar an electromagnetic system transmits signals which are intercepted by the object and reradiated in many directions, those signals directed back towards the radar are captured to detect the presence and location of object using mathematical methods.
The origins takes us back to German Physicist Heinrich Hertz (1885-1888) who experimentally verified the predictions of electromagnetic field theory proposed by James Clerk Maxwell in 1864. Hertz left the space empty to practical applications for others which was then filled by another German, Christian Hulsmeyer designing an advanced monostatic (single site) pulse radar obtaining patent at England in 1904.
Clutter can be a nuisance or an obstacle to a radar while detecting desired and undesired objects. Different radars serve different purposes, say weather radars observing earth sources actually to be carried out by surface radars, thus the same environmental echo might be the desired signal in one application becoming unwanted clutter echo in another while creating disturbance at two functions
Echoes from land, sea, air are identified as surface, volume, weather clutters with different radar applications such as detection of aircraft over land, detection of terrains for aircraft to fly around, vehicle detection, mapping or imaging, remote sensing radars, backscatter from sea ice, contaminants that change the water surface-tensions, snowfall, birds, etc, also echoes interfere mostly while celebrating festivals.
Whenever things go wrong, internet gets flooded with the comments provocating on the failure of defense which I seriously condemn. Not knowing the roots of cause but having the rights to speak make things much more worse. People need to know that the sensitive issues of a nation are not publicly addressed by the Intelligence. After thorough investigation, a protocol will be carried out when and what to be released.
I humbly ask the readers to stand up and support one’s defense. Knowing that You, I, them are reading and writing in the sense that we are being protected amidst of abyss.