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IAF to begun deployment of many LEO satellites with SAR for all weather coverage of enemy movements

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Apr 9, 2023
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CHENNAI: Space sector startup, Sisir Radar Private Ltd has hit success at the prestigious iDEX DefSpace Challenge with its projects for development of “L/P band Continuous Wave SAR (synthetic aperture radar) payload for LEO Small Satellites” and “Unfurlable, Electronically Steering Antenna for L/P band SAR payload” for Indian Air Force (IAF), said a top company official.
The company is promoted by former Director at the Indian Space Research Organisation (ISRO) Tapan Misra and the brains behind the Indian space agency’s RISAT series of SAR satellites as well as the Dual Frequency SAR on the Chandrayaan 2 orbiter that is currently circling the moon.

"A grant of Rs 3 crore is also there for development of the products," Misra told IANS.

Synthetic Aperture Radar or SAR is a special kind of imaging radar technology that can provide extremely accurate high resolution imagery of the terrain through clouds, smoke and dust even in pitch dark conditions. SAR imagery provides much higher resolution than other forms of remote sensing technology such as hyperspectral and multispectral. SAR is a critical technology for strategic reconnaissance and planning as well as for disaster management.

According to Misra, winning the challenge in just over a year of floating the company is a major booster.

He said L and P band SAR have an advantage over other frequencies (like X band) when it comes to penetration capabilities through rain, clouds, foliage and vegetation in a tropical country like India, and underground penetration capabilities in dry terrain.

Continuing further, he said the L band SAR will provide 1 metre resolution, spotlight resolution in Stripmap mode. The current industry standard is 5-10 metre in L band. Misra said both the L and P band will operate simultaneously from a satellite borne SAR. Recently, Sisir Radar successfully developed and tested the world’s highest resolution L-Band SAR fitted on a drone. With 0.2 metre resolution, this is by far the highest L band SAR in the world, he said.
RENOWNED airpower expert Giulio Douhet said, “The choice of enemy targets is the most delicate operation of aerial warfare.” Targeting involves a detailed process of selection of targets, vulnerability analysis, weapon matching and intelligence. Ultimately, of course, air targeting is all about intelligence and that means the ability to ‘see’ the enemy. This includes wherewithal in space and the use of sensors on other aerial platforms.

To that end, it was heartening to read about a Bengaluru-based space startup, Pixxel, winning a grant to manufacture miniaturised multi-payload satellites for the Indian Air Force (IAF) under the Ministry of Defence’s iDEX (Innovation for Defence Excellence) initiative. The 2019 Balakot airstrikes brought out the need for having all-weather remote-sensing capabilities, without having to rely on largesse from friendly allies for timely imagery.

Western nations such as the USA have had such capabilities since the early 1990s, like the Keyhole (KH) series satellites employed and used effectively during the Gulf War. With technology having evolved, entities are able to have state-of-the-art multispectral cameras on board much smaller, low earth orbit (LEO) satellites.

The Keyhole series and other older strategic sensor satellites were mainly geostationary, with electro-optical onboard sensors and cameras. Modern technology such as that available with the Pixxel startup, Israel Aircraft Industries and others enable low earth orbits with multispectral capabilities and high revisit times. The Shakuntala/TD-2 LEO is one such satellite, launched in April 2022 as a ‘ride share’ mission on the Falcon 9 rocket operated by Elon Musk’s Space X. Pixxel designed the TD-2 as a demonstration satellite, which is a part of a constellation of weather satellites. But once the mechanics of launch and orbital dynamics has been proven, these LEOs could well be engineered for day-and-night tactical military reconnaissance all over the world.

Pixxel claims that its micro-satellites have a resolution 50 times higher than the existing multispectral counterparts, designed for detecting, monitoring and predicting global weather phenomena. Weighing less than 150 kg, these micro-satellites have resolutions of the order of 10m per pixel, which compares favourably with the hyper-spectral cameras launched by NASA, the European Space Agency and ISRO. It has a lifespan of 10 years.

The fact that such a startup has emerged in the private sector is all the more laudable as aspects such as budgetary constraints can be addressed while collaborating with foreign vendors having deep pockets, such as Space X. Further, employing ISRO’s PSLV satellites for their launch would have attractive commercial payoffs for the nation’s space agency.The US Air Force Space Command has, of late, been exploring the use of commercial LEO and very low earth orbit (VLEO) satellites (250-300 km altitude) as options for communications and imagery. The IAF appears to be on a similar track in tactically exploiting the LEO space. The ability to have our own indigenous LEOs could dovetail with the nation’s military satellite programme seamlessly to also provide Battle Damage Assessment (BDA), again warranted during the Balakot operation.

Multispectral sensors would be invaluable for infrared and synthetic aperture radar cameras on these satellites to enable all-weather target analysis and BDA. The Pixxel satellites are expected to field sensors in the electro-optical, infrared, synthetic aperture radar and hyper-spectral applications.

An associated requirement would be to ensure the safety of LEO satellites from electronic jamming by adversaries and physical damage by space interceptors. Hence, the LEO and VLEO satellites being designed to “see and not be seen” provide better options for high-resolution imagery on low payload satellites, with obvious cost benefits for the operator.

‘The more the merrier’ is the current thinking on the exploitation of the commercial LEO space by leading air and space forces. Multispectral sensor capability on satellites would also provide the capability to detect enemy missile launches on the ground. The Ukraine war has exposed the Russian military as being virtually ‘blind in orbit’, with too few high-resolution satellites.

The sanctions on Russia by the West after the Crimean invasion have adversely impacted Moscow’s ability to get high-tech satellite technology. Typically, the best available Russian satellites’ imagery is of the order of 50 cm per pixel as compared to 5 cm for the Keyhole series and around 15 cm for private satellites, such as those of Maxar and Planet. Recently, satellite imagery available in the public domain has shown damage to Russian helicopters, ships in the Black Sea and civilian areas of Mariupol.

It is expected that the IAF would look for on-demand generation of high-resolution imagery and communication services in all-weather conditions from its Pixxel contract. Private companies in the business of selling satellite imagery would expect to raise revenue from their commercial applications. The government would have its own defence requirements for satellites. The main requirement would be to have satellites available on call to accomplish operational tasks.

Commercial satellite imagery has been available from companies such as Maxar and Planet since the Syrian war, but the Ukraine conflict has changed the game dramatically. With imagery costing as less as $10 per square km, even a hobbyist using his device can monitor wartime imagery, such as that from Ukraine and make sense of the progress of the battle.

This open-source intelligence could give resolutions as high as 3 metres as compared to the classified imagery sold at a premium by professional agencies.

The advent of private satellite imagery companies into the IAF’s targeting ambit augurs well for the future of sophisticated open and classified intelligence wherewithal for aspiring nations and private players.
The Indian Army’s first dedicated satellite GSAT-7B will be launched for Rs 4,635 crore towards end-2025

Currently, India has only two dedicated military satellites — the GSAT-7 (Rukmini) and GSAT-7A (Angry Bird) — used by the Indian Navy and Air Force respectively.

What will be the role of the GSAT 7B satellite?
●Till date, the Indian Army has been dependent on GSAT-7A and other satellites, but with this new state-of-the-art technology, the Indian Army will have new eyes in the sky.

●The military-grade satellite will be a force multiplier in providing fail-safe communication support.

●The GSAT 7B will primarily fulfil the communication needs of the Indian Army.

While many features of this satellite are still a closely guarded secret, it is expected that the state of the art, multi-band, military-grade satellite shall be a shot in the arm for the communication and surveillance needs of the Indian Army.

●The use of such a satellite would also mean that the Indian Army's vast array of radio communication equipment could come under a single platform.

●The GSAT-7B is a step in the right direction, but India has a long way to go before it can have near real-time imagery or electronic intelligence, which is often essential in maintaining the tempo of modern warfare.
What other kinds of military satellites does India have?

●An Electromagnetic Intelligence Gathering Satellite (EMISAT), developed by ISRO, was launched in April 2019 through a Polar Satellite Launch Vehicle(PSLV-C45).

●It has an Electronic Intelligence (ELINT) package called Kautilya, which allows the interception of ground-based radar and also carries out electronic surveillance across India.

●This satellite circles the globe pole-to-pole, and is helpful in gathering information from radars of countries that have borders with India.

●India also has a RISAT 2BR1 synthetic aperture radar imaging satellite, which was launched in December 2019 from Sriharikota

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