Tag: GS 3 || Science & Technology || Defence || Military Technology

Why in news?

• Prime Minister Narendra Modi’s comment about how he gave the go-ahead for the Balakot airstrike despite bad weather as the clouds would enable Indian Air Force fighter jets to evade enemy radars, has raised a storm on social media.

What is a radar?

• Radar stands for radio detection and ranging.
• Components of radar: A radar typically has a magnetron, transmitter, receiver, and a screen.
• Basic principle of a radar: The magnetron generates radio waves which are released through an antenna in different directions at certain time intervals.
  • If there is an object in the air, an aeroplane for instance, the radio waves hit it and bounce back, to be caught by the receiver of the radar.
  • By mapping the reflected waves on a screen with a grid map, the aeroplane is displayed as a blip on the screen and its movement is shown as the radio waves strike it at intervals. This is the basic principle of a radar.
• Over the decades, there have been tremendous technological advancements in radars, making them highly sophisticated and powerful.

Do clouds hinder radar?

• By virtue of being radio waves, radars can see through cloud cover, and during day and night. In fact, that is what they are meant to do.
• Commercial flights continue taking off and landing at the airport despite the rough weather and overcast skies over a city. This is because the Air Traffic Controllers (ATC) across the world depend on radars.
• All ATCs have two radars – primary and secondary.
  • The primary is a classic radar based on the principle described above.
  • The secondary radar identifies the details of the aircraft by communicating with the transponders on the aircraft.
• Thus, radars enable continuous airport operations in cloudy conditions.
• And that goes for military radars as well, including those of Pakistan, which has an advanced military.

Origin of Radar

• The origin of the radar goes back to World War II, when the first radar was demonstrated in Britain in 1935. By the time the war began, Britain had a chain of radars along its coast to detect intruders. And by the end of WW-II, all major countries involved deployed radars.
• Ground based radars have limitations primarily due to the curvature of the earth. So radars were mounted on aircraft which fly thousands of feet above the ground with 360-degree coverage. These are known as Airborne Warning and Control System (AWACS), and are major force multipliers in today’s battlefields.
• During the Balakot airstrike on February 26, IAF had fielded both indigenous and Israeli AWACS to direct the fighters jets on their strike mission and monitor the skies for any movement by Pakistani jets.

Clouds can affect weaponry

• While radar can see through cloud, there are weapon systems that are affected by clouds, such as television-guided missiles.
• A TV-guided missile is an air-to-ground missile, controlled remotely by a pilot, who steers it using the live images it sends. Clouds could also affect “scene-matching weapons” fired from an aircraft. The missile matches pre-programmed images to its live feed.
• In Balakot specifically, the air force’s SPICE-2000 missile–made in Israel–was used for the air strike. This is a precision weapon that –
  • uses satellite data in the initial phase of its flight after release;
  • towards the terminal phases of the flight, it uses a digital map to strike the target.
• Such missiles use a combination of satellite and pre-programmed guidance and may be affected by low-lying clouds during its “terminal stage”.

Additional info

Radar evasion

• Over the years, as radars have improved so have the technologies to evade them. There are many ways of evading radars or reducing the radar cross section or foot print.
• That’s where the concept of stealth comes in. Stealth is a relative concept and not absolute.
• Radars essentially identify an object by the reflected radio waves. So if the radio waves can be deflected away from the receiver, that reduces the footprint.
  • A classic example for this is the US F-117 which is now out of service.
• Another way is to absorb some or most of the radio waves with radar absorbent paint, and changing the shape to minimise the cross section.
  • The iconic US B2 bomber is a perfect example for this.
• The latest stealth planes F-22 and F-35 use a combination of these to evade radars.

Mains question

• What is radar? Describe the working of radar. Also enumerate its various applications.