Intern spends summer with ASF

by Steven Balistreri

After a winter of data calibration research and planning, the ASF Data Quality group geared up for a summer of new beginnings. The short season in Alaska provides suitable weather for numerous hardware maintenance, retrieval and deployment tasks. This year produced several elaborate creations that will move ASF data calibration into the years ahead.

Advances this year were made with the support of Ernst Weissbrodt, a student of electro-engineering from the University of Karlsruhe, Germany. Each spring, ASF welcomes an intern to assist with the added workload that includes building, improving and recovering remotely located data calibration equipment.

Weissbrodt arrived at ASF in late April, when Alaska’s interior was still swept with snow. The schedule of summer projects included a slew of trips through Alaska, from Prudhoe Bay to Delta Junction. Along the way, Weissbrodt experienced his fair share of wildlife encounters including caribou, moose, buffalo, musk ox and brown bears.

Under the leadership of Wade Albright, the ASF Data Quality group focused work on advancing its hardware fleet. The portable reflector design ASF developed last summer has been revisited with a new, collapsible generation of 2.45-metertrihedral corner reflectors. “Design research is an ongoing process” says Albright, “With the intention of utilizing corner reflector calibration methods for a variety of data types and applications.”

Five 1.8-meter, portable reflectors were constructed to provide permanent scatter and tie points in remote locations that will likely include Chena Hot Springs and various Aleutian islands.

Deployment sites in Fairbanks and Cantwell, Alaska were developed to provide increased coverage supporting ScanSAR geometric calibration. In addition, a number of 3-meter reflector skirts, or extensions, were constructed and deployed to increase reflective surface area.

Although not all design projects make it into the field, the Data Quality group is always testing its boundaries. Weissbrodt was challenged to explore modifications that could improve the reflected signal of the trihedral design. This task included drafting and testing both alternative corner reflector configurations and an experimental conical reflector. “Initially I had my doubts,” said Weissbrodt, “but after we had the prototype, I really wanted to see the results.”

The work of ASF interns is often integrated into the everyday development of calibration work. When it comes to projects like these, Albright says, “We often work with the extended university community and it always pays off.” The mix of professional and educational resources at ASF is a bonus for interns and ASF alike. According to Weissbrodt, one of the benefits of working in a research institution is that the work is not entirely abstract, “It’s a reward to see that at the end of all this theory there is a nice, working image for researchers to use.”

Weissbrodt brought more than just enthusiasm to the table. Since 2004,Weissbrodt has been studying space electronics, telemetry and microwaves in relation to the German Aerospace Centre (DLR) TerraSAR X satellite calibration. “His experience significantly reduced the learning curve,” according to Albright.

Weissbrodt toured other parts of the United States on his way back to Germany while ASF reviewed the conical reflector test results. Weissbrodt’s methods and results will benefit ASF as the SAR community shifts toward polarmetric instruments in the years to come. Likewise, Weissbrodt will take
more than lasting work experience back home, “I liked the contrast of being in the office, working on technical things like satellites and remote sensing, then being in the middle of nowhere, among bears and caribou on the weekend.”

Next spring, the Data Quality group will be deploying five corner reflectors in the Amazon Rainforest in preparation for new calibration efforts. Read more about upcoming data calibration projects, corner reflectors and ASF internships at ASF online: www.asf.alaska.edu.

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