Next-generation radar receiver to provide scientists with improved weather data


Bistatic Radar Receiver for Global Navigation Satellite System (NGRx)


An SMD-sponsored team is developing a new radar receiver that will allow future space tools to process more signals and produce much higher-resolution data – significantly improving the ability of scientists to study storms, observe polar ice, and predict floods and to measure the height of the sea surface.

In 2018, a constellation of CYGNSS satellites allowed researchers to collect measurements of wind speed from Hurricane Sergio, seen here passing over the Pacific Ocean. The improved bistatic radar receiver will make future CYGNSS tools even more useful for researchers studying complex ground systems. Image Credit: NASA / Jesse Allen

Bubble hurricanes cost coastal communities around the world millions of dollars and thousands of lives each year. Learning more about these complex storm systems will allow researchers to improve predictive weather patterns and predict severe storms with greater ease.

“We can’t control severe weather, but we can minimize their impact on human populations by giving people more time to prepare,” said Christopher Ruff, a professor of climate and space science at the University of Michigan. Arbor.

Rufus, who also serves as principal investigator for NASA’s Cyclone Global Navigation Satellite System (CYGNSS) mission, has already developed a small constellation of micro-satellites that helps scientists measure wind speeds over the Earth’s oceans. Now, with the support of NASA’s Earth Science Office, Rufus wants to develop a new bistatic radar receiver that will significantly improve the quality of data collected by future CYGNSS satellites.

“These satellites are a big advantage for scientists who want to study not only cyclones, but also things like moisture in almost the soil surface and the extent of microplastic debris in the ocean. This new receiver will make future components of the CYGNSS system even more valuable to terrestrial scientists, ”said Rufus.

The Pegasus XL rocket launched the first payload of CYGNSS instruments into low Earth orbit (LEO) in 2016. At a distance of about 12 minutes, these eight small satellites use signals from existing GPS instruments to monitor the Earth by scattering. While most spectrometer instruments have both a transmitter and a receiver, CYGNSS satellites take advantage of existing radar signals to reduce overall complexity and space costs.

“Skaterometry uses a transmitter to transmit radar signals to the earth’s surface and a receiver to determine how strongly these transmitted signals are reflected from Earth back into space. Within a tool package, this payload becomes quite heavy. By using the radar signals produced by GPS satellites that are already in orbit, we can remove the transmitter component from our instruments and still produce excellent data, ”said Rufus.

But there is room for improvement. The CYGNSS satellites currently orbiting the Earth can only process four transmit signals at a time, which limits their accuracy. In addition, CYGNSS satellites can only process L1 signals that are transmitted at a frequency of 1575.42 MHz. This has a negative impact on both the horizontal and vertical resolution of the data collected, making it difficult to use CYGNSS to study phenomena such as ice thickness and polar ice.

“CYGNSS has performed remarkably well over the last few years, but as we expand our mission to include more scientific areas, we will need to improve some components of these tools,” Rufus said.

Its next-generation bistatic radar receiver of the Global Navigation Satellite System (NGRx) will do just that, increasing the scientific utility of CYGNSS instruments for studying complex terrestrial systems. Instead of processing only four L1 radar signals from GPS satellites, future instruments equipped with this receiver will be able to process up to fourteen L1 and L5 radar signals from GPS and Galileo satellites.

“As a result of these changes, the horizontal resolution will be improved by a factor of three, the vertical resolution will be improved by a factor of ten, and the spatial coverage by a factor of at least two, maybe even four,” Rufus said.

This improved resolution will allow researchers to better study storms, more clearly monitor the extent of polar ice, develop better models for flood forecasting, and even measure the sea surface at a level of detail that surpasses current instruments. of CYGNSS with a factor of ten.

“Having these capabilities on board cost-effective small satellites is pretty amazing. We will be able to produce excellent science at a much lower cost, “Rufus said.

The Instrument Incubation Program (IIP) at NASA’s Office of Earth Science Technology is dedicated to helping researchers like Ruf develop their instrument concepts into fully functional sensors. In particular, the IIP provided Ruf with critical funding and expertise as it developed its next-generation radar receiver.

Although the bistatic radar receiver is not quite ready to go into space, it is ready for substantial tests in the air. Partnership with the Ministry of Business, Innovation and Employment of New Zealand; New Zealand Space Agency; Air New Zealand; and the University of Auckland; Ruf plans to fix a prototype of its sensor to a Bombardier Q300 passenger plane. Rufus’ sensor will collect ocean data as aircraft operate routes through New Zealand, helping his team determine if the instrument is ready for space applications.

“We are excited to be working with our colleagues in New Zealand to prepare this radar receiver for space. It was very satisfying to take something that was just an idea and develop it into a working prototype, and we are excited to send this tool into space one day soon, ”said Rufus.


Christopher Rufus, University of Michigan, Ann Arbor


Instrument Incubation Program of the Earth Science Department

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