Articles for "Radar"

to homepage
Space | 02. November 2023

What is new about the German radar satellites?

Die Mission TanDEM-X
Credit: DLR
The twin satellites TerraSAR-X and TanDEM-X fly in close formation – only a few hundred metres apart – and collect data for digital elevation models

Earth is a complex and dynamic system and radar remote sensing is designed to deliver quantitative 3D and 4D information about the planet's surface. The latest research results and information products obtained from high-resolution data acquired by the German satellites were presented during the TerraSAR-X and TanDEM-X Science Team Workshop, which was held at the German Aerospace Center from 18 to 20 October 2023. read more

Space | 24. October 2023

On Innovative Reference Targets and Analysis-Ready Radar Data

Dual-Band (L/X) Kalibrierungstransponder zur Unterstützung zukünftiger Satelliten-SAR-Missionen

World-leading experts for the calibration of spaceborne SAR systems met in Oberpfaffenhofen

Credit: DLR (CC BY-NC-ND 3.0)
(Top centered figure): Recently deployed innovative dual-band (L/X) calibration transponder to support future satellite SAR missions (detail)

How to define and ensure the data quality of state-of-the-art spaceborne radar satellites? How can synergies between various current and future radar missions be leveraged? How to ensure comparability between radar data acquired by missions operated by different national and international space agencies? And how can complex data sets acquired by different radar satellites be processed in such a way that they can be used by non-radar experts?

To discuss these and many other questions from the field of calibration of satellite radar missions, an international community of radar experts met at the Microwaves and Radar Institute of the German Aerospace Center (DLR) in Oberpfaffenhofen for the annual meeting of the CEOS WGCV SAR Subgroup on Calibration and Validation of High Resolution Synthetic Aperture Radar (SAR) Sensors. read more

Aeronautics | 02. June 2015

ARCTIC15 - Airborne SAR acquisitions up and running

SAR-Daten
Credit: DLR / Martin Keller (CC-BY 3.0)
A first SAR data quicklook of the Kangerlussuaq calibration test site. The colours represent the intensity in different polarisations (Red: VV, Green: HV, Blue: HH). The airport is clearly visible in black. From the centre of the image, the fjord extents in a south-west direction, where skidoo-tracks to the next village can be seen.

Three calibration flights, 10 flights to test sites, and over 100 radar data sets resulting in 4.8 Terabyte of SAR data. These are the numbers behind the work our F-SAR team conducted within the last two weeks – including even the alteration from the X-C-S-L to the P-band antenna configuration and fortunately only one bad weather day.

DLR's Do-228 airplane, with the F-SAR system on board arrived on Friday, 24 May, in Kangerlussuaq. On the following Monday, the team consisting of two pilots, one flight engineer and two radar operators took off for the first calibration flight. In the first two weeks, the antenna configuration for the X-, C-, S- and L-band frequencies was installed on the plane. This range of different frequencies will allow us to compare radar acquisitions with different penetration depths into the snow and ice. The team acquired SAR data over all the test sites where we had installed corner reflectors. Additionally, the area around the airport and town of Kangerlussuaq is overflown for calibration purposes and is well equipped with seven reflectors. It seems like the locals got used to these strange metallic artefacts in their town pretty fast.

Credit: DLR / Ralf Horn (CC-BY 3.0)
DLR's Do-228 with the F-SAR radar system on board after refuelling at the airport of Ilulissat, Greenland. The X-C-S-L antenna mount is visible on the rear of the plane.

Eventually, during the first days after the calibration flight, we had to face exactly those smaller and bigger problems – those that one must always expect during a campaign, as mentioned in the previous post. But the F-SAR team proved their problem-solving skills and campaign experience. From non-matching connections of the local oxygen supply to unstable electronic parts, they were able to fix everything without causing any delay to the campaign plan. I have to admit that I was already worried about losing one test site due to the technical difficulties, but the team was able to acquire almost all the data we had planned for. For now, we can say that the X-C-S-L phase was successful, giving us plenty of scientific data.

Credit: DLR / Georg Fischer (CC-BY 3.0)
The F-SAR team preparing to remove the X-C-S-L antenna from the side of the Do-228 airplane.

The change to the P-band antenna configuration was completed successfully. The P-band wavelength is the longest we will use during this campaign and penetrates several tens of metres into the ice. We are already curious about what kind of subsurface features we will see in the data.

Today, while I'm writing, the F-SAR team is flying over the K-transect to conduct the first P-band acquisitions. Currently, we are all very optimistic about the upcoming part of the campaign.