It is easy to catch a big fish, but small fish can easily escape from the net. 

And such small fish are artillery fire for an army, which becomes the reason for more casualties of the enemy’s army in a war.

And we have seen its example in the Kargil War of 1999 when undetectable artillery fire coming from Pakistan. That became the reason for the causality of 80% more Brave Soldiers of our country.

And it broke the patience

Result of which is the Swathi Radar system

So first we know

What Is The Swathi Radar System

Swathi Radar System is a weapon locating radar (WLR) that accurately detects and tracks the incoming artillery rounds and rocket fire from the enemy side.
So that artillery locations can be detected and counter-battery-fired on them.

It was jointly developed by the Electronics and Radar Development Establishment (LRDE) and Bharat Electronics Limited (BEL). The LRDE is a lab of the Defense Research and Development Organization (DRDO).

It was inducted into the Indian Army in 2008 but the Indian Army was declared its requirement in the 1980s. When the USA conducted initial tests of its Weapon Locating Radar (WLR) AN/TPQ-37 & 36 fire finder in May 1982. Then in 1989, the Indian Army had talked about buying them, but the USA refused to sell.

In 1995, the Indian army again issued a Request for Proposal (RFI) for 5 Companies, to which only one company responded that was Hughes (now Raytheon). But Hughes did not manage to reach the General Staff Quality Requirements (GSQR) of the Indian Army.

In 1998, Once Request for Proposal (RFI) was again issued for emergency purchases that included companies from the USA, France, and Ukraine.
Companies of USA and France refused because USA and France banned India due to Pokhran-2 Nuclear Weapon Test.

And the third company was ISKARA from Ukraine, with which no conclusions of negotiation came.

After the Kargil War in 1999, the contract to develop the weapon locating radar (WLR) was signed with DRDO. And DRDO has developed it in collaboration with BEL.

So Before moving to how Swathi Radar works we know

The Design Of The Swathi radar System

Swati radar is a derivative of Rajendra radar which is the Fire central radar of the Akash missile system. During the trial run of the Akash missile system, engineers at ITC Chandipur found that this radar can detect and track artillery shells at close range.

Receiving the Signals

It is a Passive electronically scanned array (PESA). It is called passive radar because it uses a single transmitter (TX) to connect all antenna elements (Φ). And the antenna of Swathi is not turnable during the operation.

In simple words, In the Swathi radar, the same antenna is used to transmit and receive waves, So to get back the transmitted waves, it has to be kept stable.

The radar can electronically scan a +/-45° range of azimuths and -5 to 75° of elevation for incoming rocket, artillery, and mortar fire.

In case of any incoming threats, the radar can be quickly moved out of the threat area. And its antenna can be turned to +/-135° in just 30 seconds, which quickly changes its scanning area.
And we can scan the whole 360° turning like this.

Each the azimuth and elevation angles from the radar to the target can be determined, after measuring the direction in which the antenna is pointing while the echo is obtained.

So the azimuth and elevation angles both are not directly related to the operational capabilities but when you deploy the radar it will give you an idea of the right deployment location. And the right location of radar is very important to track incoming artillery rounds.

Swati Radar consists of a Traveling-Wave Tube (TW) based transmitter that releases monopulse signals. And the pulse compression of these monopulse signals is used to track the target. Performing pulse compression increases the range resolution as well as improves the radar’s flame probability of intercept capability.

Processing Of The Signals And Turn It Into Data

After receiving the signal, the weapon locating radar processor’s algorithms process these real-time signals.
The algorithm is based on a modified version of the Runge–Kutta method, with the use of a constant false alarm rate (CFAR) for accurate target detection.

And now, the data is sent to a digital signal processor to process the data that comes with two modified extended Kalman filters, one with six states, and another with seven states.

The Moving Target Indicator (MTI), Airborne MTI (AMTI), and Fast Fourier Transform (FFT) reject the remaining useless clutter.

Display The Data

The information is displayed on ruggedized Power PCs with a high-resolution, multi-mode, color display. The data is displayed in real-time and can be overlaid on a 100×100 Km, 3-D digital map that was stored in WLR.

Swathi WLR is capable to store and track the location of 99 weapons at any point in time. And it can be transmitted to the command center.

Now you capable to understand that

How Swathi Radar System Detects So Small Artillery?

As you know, Swati radar is a derivative of Rajendra radar which is the central fire radar of the Akash missile system. And this radar can detect and track artillery shells at close range.

So it has no specific technology to detect the small target. But much up-gradation was acted on this that’s why we should know about this DRDO’s powerful technology.

Detect Smartly & Process Precisely

Inside the Swathi WLR is a traveling-wave tube (TW) based transmitter that amplifies and emits microwaves over a wide range.

Due to the wide range, the transmission of data becomes faster, which reduces the range resolution of the waves.

But the monopulse tracking system is used to increase the range resolution. In this technique, the microwave, which is a type of pulse wave, is compressed to reduce the pulse width that increases the range resolution.

All elements of Swathi WLR’s antenna transmit a pulse wave/microwave simultaneously at the same time. The amplified fluctuation is very low in the monopulse tracking technique, which increases its accuracy to a great extent.

And when multiple elements of the antenna send and receive multiple pulse waves, the area is scanned in a short amount of time after processing the large amount of data received through the received signals.

The signal-to-noise (SNR) ratio of a monopulse tracking system is higher than that of other tracking systems. It means more signal is received and less noise/clutter who makes it more useful in extreme weather conditions.

At the time of sending pulse waves, their phase remains the same. But on getting back the phase changes. And the return time of each wave is also different because each wave comes back after hitting different artillery rounds.

After comparing the amplitude and phase of these waves the projectile angle is determined. With the help of traveling time and wave speed calculate the distance between the target and the radar.

And from this, the artillery location can be easily detected using simple math formula.

Data processing is the same as what we know in the upper section [Processing of the signals and turning them into Data].

Check The Operational

Specifications of Swathi Radar System

These are the SPECIFICATIONS that pushed the Indian army to buy 12 more made-in-India Swathi radars for the china border.

1. Swathi WLR can track and detect 3 Types of targets.

Large Caliber Artillery → 2-30 Km
Unguided Rockets → 4-40 Km
Mortars → 2-30 Km

2. A powerful algorithm and strong design coded inside this radar can track 7 targets simultaneously.
And its same specifications make it effectively operable in severe radar clutter and jamming conditions.

3. The radar can track rounds fired at both low and high angles, and all aspect angles – from behind or towards the radar, or at an oblique angle to the array. The WLR features adaptive radar resource scheduling to boost efficiency and trustworthiness.

4. As we know it, it can quickly change its scanning area in 30 seconds, so that it is capable of scanning full 360°.

5. After detecting the incoming rounds, and classifying them as threats, simply observe their track sequence and starts searching for new targets. The incoming round’s trajectory is tracked, and a computer program analyses the track data and then figures the round’s point of origin.

6. This calculated point of origin is then reported to the radar operator and can be stored up to 99 target locations with broad digital map displays thus allowing friendly artillery to direct counter-battery fire toward the enemy artillery. And this specification makes it more deadly.

So now we reach the End of this Deadly adversary who is capable and always ready to give a befitting reply to the enemy’s artillery fire towards the Border.