Images beamed down from Cartosat-2E, India’s latest earth observation (EO) satellite, proves its ability to capture images of trucks and army columns from space, boosting the country’s ability to monitor its borders and internal regions for security purposes.

Still, there’s a long way to go before we can see and recognise faces like in the James Bond movies.

The first lot of images from the Cartosat-2E, launched June 23, are better than images from India’s previous EO satellites when it comes to detail and resolution of the images, but the imaging capability of the Cartosat-2 series clearly lags behind global leaders.

If you look at the entire array of satellites for mapping being launched around the globe, India is a generation behind what is today considered state-of-the-art. To be sure, it’s been only 12 years since India entered this activity — Indian Space Research Organisation (Isro)’s Cartosat-1 was launched in May 2005.

Why EO satellites are important

Spatial resolution — the detail visible to human eyes in an image — of any imaging system, including a satellite, is usually expressed in metres. The lower that number, the more the detail that can be seen in the images.

The Cartosat-2C satellite, launched in June 2016, was the first in the Cartosat series to offer 0.6 metre resolution. The imagery from this satellite was used by Indian defence forces to conduct surgical strikes in Pakistan last September, according to reports.

“It is of strategic importance because our own satellite, which we control in a time of crisis, is crucial especially if other satellites shut off,” said Lalitesh Katragadda, former Google India head and creator of Google Map maker. Having multiple EO satellites helps a country map the same area for precise information on enemy movements and other purposes.

Isro spokespeople could not be reached for comment for this story despite multiple attempts.

The space organisation has so far launched six indigenously built EO satellites as part of the Indian Remote Sensing Programme. The first Cartosat series satellite, the Cartosat-1, was launched on May 5, 2005. Cartosat-1 was fitted with a panchromatic camera that took black-and-white pictures with a spatial resolution of 2.5 metres.

Most of the Cartosat-2 series satellites offer a sub one-metre spatial resolution, but this resolution has been available in the global market for at least for two decades.

What is state of the art

In terms of image resolution, the WorldView-4 satellite, previously known as GeoEye-2, is known to be the gold standard when it came to commercial satellite imagery. Launched in November 2016, the DigitalGlobe-operated satellite has a spatial resolution of 0.31 metre.

Other satellites from companies such as Earth-i  are also capable of providing services like images and full motion, high-definition colour video with resolutions better than one metre. This comes useful for visuals of moving targets such as vehicles, vessels and aircraft.

These services also offer higher scan frequency by revisiting the same location multiple times per day.

Also, an alternate method for mapping imagery is using aircraft and drone-based imaging systems as these offer the same or better resolution than satellite imagery in urban areas. These are cheaper and offer resolutions of up to 0.02 to 0.05 metres as compared to satellite imagery

What more from Cartosats

The Cartosat series of satellites play a crucial role in serving India’s remote sensing civilian needs, too.

These satellites are also used to assist in fields like agriculture (crop monitoring, crop yield and damage assessments), forestry (habitat analysis, encroachment, fire damage), environmental monitoring (soil contamination, desertification analysis, environmental impact assessment), geology and exploration (rock type mapping, mining pollution assessment, coal fire analysis landslide).

The next generation of Cartosat series, the Cartosat-3, which will reportedly offer a resolution 0.25 metres, is expected to be launched by Isro in 2018.

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