Is Synthetic Aperture Radar (SAR) ONLY A MATTER OF RESOLUTION?

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Over the past 5 years, disruptive constellation projects have emerged and completely changed the way SAR is being used, promoting access to new end-user communities, and opening up new applications. “Two key historical barriers have been overcome for SAR Imaging to break into the mainstream commercial market: the cost of data and processing complexity” said Alexis Conte, Editor of the Earth Observation Data and Services Market research report and Senior Consultant at Euroconsult.

However, the main challenge is to find the sweet spot between resolution and other parameters. This article dives into the current development strategy of constellation projects and explores what they are really designed for.

Euroconsult identified more than 10 SAR companies that have announced plans to develop commercial constellations over the next five years. A common thread is that all these projects are focusing on the X-band domain thus paving the way for Very-High-Resolution applications at the expense of other capabilities such as a wider surface penetration capability (e.g., C-band or L-band). The main challenge is the same as for optical multispectral constellations – to build cost-effective systems that can provide high-revisit data for building change detection analytics.

In interviews Euroconsult had with various companies, business models differ from one company to another. While some focus on selling only data (such as Umbra or PredaSAR), others are focusing on selling standard or turnkey services in addition to imagery (Iceye, Capella or Synspective for instance). Another common thread identified is that, despite being 10 times lighter than the 1,000kg class of state-of-the-art commercial systems such as TerraSAR-X, these companies’ satellites have the capacity to reach a slant range resolution as good as the incumbent satellite operators. This mass reduction in turn pushes down the CAPEX per unit, decreasing the data’s price point, which can be leveraged to build services on top of raw imagery at competitive price points.

So far, the development process strategy has been iterative for Smallsat constellations. For instance, the initial batch deployment of Iceye or Capella started with low performance of around 2-to-10-meter resolutions to test the system. The second generation had resolutions below 1 or 0.5 meter – sometimes increasing the mass from  37kg to 110kg

as for Capella Space – and are now targeting below 0.25m. Whether other companies will emulate this incremental roll-out strategy, or immediately launch satellites with the lowest possible resolution, remains to be seen. Umbra just revealed it will be able to reach 0.15m in Ground Sampling Distance (GSD) resolution for U.S DoD users and their allies, leveraging high-bandwidth SAR using the 1,200 MHz band.

Comparing smallsats with traditional SAR satellites

Resolution is not everything, and other factors can also strongly influence market positioning and technical parameters of SAR smallsat constellations. The Noise of Smallsat constellations (NESZ) or the contrast between objects, is not as good as for traditional satellites (TerraSAR-X class). The same goes for polarization: constellations only offer single polarization regardless of the mode, while traditional satellites can offer dual or quad polarization, which improves crop classification, land cover, forest type or condition, soil moisture, hydrology and improves ship detection. Smallsats also offer fewer modes of acquisition: coarser resolutions with larger swath “WideScan mode” are not available on Smallsat constellations. Finally, geolocation accuracy is much better for traditional players: Iceye X-5 is assessed between 6.6m-9m CE90 compared to the 1m TerraSAR-X in spotlight mode. As a result of these limitations, some markets can be more difficult to target considering the competition with incumbent players. However, the high revisit offered by constellations can be interesting as a complement in some cases or can totally disrupt the market at a very competitive price point by opening up new applications requiring almost permanency.

Source: Euroconsult “Satellite-based Earth Observation, Market Prospects”, rebranded “Earth Observation Data and Services Market”, 13th edition, 2020.

The markets that high frequency and very high resolution open up are primarily defense applications through the sale of images and services. In contrast, finance, energy, and infrastructure monitoring amongst other civilian applications are more Value-Added Services-oriented.

SAR players and regional markets: With the clear understanding that the main demand drivers are defense clients, many regions are deploying SAR constellation projects to serve various national defence needs. Capella Space initially emerged in the US, Iceye in Europe, Synspective or iQPS in Japan and now Spacety in China. This geographical distribution emphasizes the interest of SAR constellations for sovereignty issues. After securing contracts with defence clients, the companies then target markets such as finance, energy, infrastructure monitoring, agriculture, disaster response and so on, which generated tier-two revenues (but with a strong growth potential). These are new markets, new applications and new customers, and we expect great dynamism in these areas over the coming decade.

Meanwhile, many other projects are in the pipeline in the US like Umbra, PredaSAR or EOS. There is also significant (yet less transparent) activity in China. Looking ahead, the multitude of actors and projects will have to differentiate their offering or pricing strategy; otherwise an industry rationalization risks to absorb or sink many of them.

ALEXIS CONTE IS A SENIOR CONSULTANT AT EUROCONSULT WHERE HE FOCUSES ON A WIDE RANGE OF SATELLITE AND AERIAL EO APPLICATIONS. HE PREVIOUSLY WORKED FOR THE FRENCH AGRICULTURAL MINISTRY AND EARNED A MASTER’S DEGREE IN APPLIED GEOGRAPHY FROM LA SORBONNE UNIVERSITY.

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