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Radar Applied to Missions Large and Small—Part 1

May 30, 2023 by Aaron Carman

Whether it’s planetary-level trends or human body imaging, the latest advances in radar technology allow designers to remotely sense trends at any scale.

Be sure to check back on Thursday for Part 2 of this series.

Radar has been in use for well over a century. But researchers at the recent 2023 IEEE Radar Conference (RadarConf 2023) are still finding new and unique ways to use radar to accomplish remote sensing. The keynotes of the conference highlighted the flexibility with which radar can be used to gain information, discussing applications ranging from detecting long-term planetary trends to new healthcare imaging techniques.

 

The 2023 IEEE Radar Conference took place in San Antonio, TX, and highlighted new radar applications both large and small from industry and academia.

The 2023 IEEE Radar Conference took place in San Antonio, TX, and highlighted new radar applications both large and small from industry and academia. Image used courtesy of the IEEE Radar Conference

 

In part one of this two-part series, we will look at two key applications that use the same fundamental technology to build two vastly different sensors and discuss how radar can be leveraged to enable access to all new sources of information in applications at any scale.

 

Breaking the Ice with Radar

Kicking off the plenary session, Dr. David G. Long discussed an application of radar used in his research group that falls firmly within the “Large” category: iceberg, environment, and climate monitoring with radar scatterometry.

Radar scatterometry leverages the dynamic properties of the earth in order to extract information such as wind or water speed from the relative comfort of space, but its uses can be greatly extended. One key example given by Dr. Long was the Deepwater Horizon oil spill, where radar was used to monitor the levels of surface oil after the spill.

 

Dr. Long highlighted the radar view of the Earth and how it can provide considerably more information versus purely optical images.

Dr. Long highlighted the radar view of the Earth and how it can provide considerably more information versus purely optical images. Image from All About Circuits’ attendance of RadarConf 2023

 

Space-based radar has also been used as a key source of information when modeling the Earth’s climate for both land and sea-based environments. Changes in the Amazonian ecosystem due to infrastructure development or deforestation have been observed by radars onboard satellites, allowing for a long-term comparison of the vegetation levels.

 

Using radar to track iceberg numbers and movement provides more long-term data due to its cloud-penetrating nature and its ability to work without illumination from the Sun.

Using radar to track iceberg numbers and movement provides more long-term data due to its cloud-penetrating nature and its ability to work without illumination from the Sun. Image from All About Circuits’ attendance of RadarConf 2023

 

Outside of land monitoring, radar has also been used to detect changes in the number and behavior of small icebergs coming from the Antarctic, a unique byproduct of climate change. In this application specifically, radar offers the unique advantage of penetrating through cloud cover, an important characteristic when satellite passes may be few and far between.

Although the images produced are relatively low resolution, Dr. Long said, “The radar independently, with all other sensors, confirms the changes going on in the Arctic on multi-decadal scales,” highlighting the valuable long-term information that radar can provide climate scientists. And with an increasing number of Earth-centric missions such as the NASA JPL SWOT mission, it seems that we’ve only seen the beginning of radar’s usefulness in better understanding our planet.

 

Rapid Radar Tumor Imaging

On the smaller side of things (at least smaller than an iceberg), radar has also been used as a diagnostic tool for healthcare applications, with researchers at the University of Calgary led by Dr. Elise Fear aiming to detect and monitor tumors in the breast. Dr. Fear presented her group’s work at RadarConf 2023 and highlighted the key features of radar that make it an effective medical tool.

 

Microwave imaging for body tissues can take several forms, with radar being used to measure the dielectric properties of tissues to isolate any abnormalities caused by tumors.

Microwave imaging for body tissues can take several forms, with radar being used to measure the dielectric properties of tissues to isolate any abnormalities caused by tumors. Image from All About Circuits’ attendance of RadarConf 2023

 

When it comes to robust imaging, multiple receivers are generally required to provide enough spatial diversity to form an image. This typically increases the size and cost of the system, as well as decreases the comfort of the imaging process for the patient—for example, maintaining stillness during an MRI

On the other hand, radar sacrifices resolution for a big leap in reported patient comfort, making radar-based imaging a good candidate for first-pass diagnostics where ultra-fine resolution may not be required.

 

Reported patient results showed consistent imaging for each volunteer independent of patient-specific parameters, allowing for a rapid examination of body tissue in a less-invasive manner.

Reported patient results showed consistent imaging for each volunteer independent of patient-specific parameters, allowing for a rapid examination of body tissue in a less-invasive manner. Image from All About Circuits’ attendance of RadarConf 2023

 

Another key metric for successful imaging is consistency. As Dr. Fear said during her lecture, “These applications rely on our ability to collect consistent data. So, if I scan a patient now, two weeks from now, or a month from now, do I get the same picture or something completely different?”

While radar may not have the resolution of other imaging methods, the consistency of radar imaging in diagnosis is certainly not lacking, with results reportedly staying consistent with patient histories and other imaging mechanisms.

So, while it may not be realistic for radar imaging to replace radiation-based imaging any time soon, the addition of a new, comfortable tool for medical professionals to use is certainly a benefit for all and illustrates how radar can be used in almost any sensing application.

 

A Radar for Any Task

It’s not often that a technology just past its 119th birthday is still being developed so rapidly and fervently by both industry and academic researchers. Radar, however, is still proving itself to be more useful than could’ve been imagined, with its incorporation with satellites, drones, and automobiles providing new and robust sources of information.

At even smaller scales, radar can even be used to detect gesture signatures for truly remote-controlled applications, enabling greater levels of accessibility.

It's not just radar researchers who believe that radar will be an enabling technology in the future, with companies such as Tesla leveraging radar to allow improved autonomy in their vehicles and NASA JPL using interferometry to measure the ocean surface. And while the underlying principle of transmission and measurement of the reflection is the same whether you’re in space or on the road, the breadth of methods for extracting information make radar technology as a whole a broadly applicable solution for sensing at any scale.