65th IHC Booklet/Program (pdf - 4.9MB) - Office of the Federal ...

Developments in 2010 in in-flight real-time reporting of the directional ocean wave spectra
using Wide Swath Radar Altimeter (WSRA) from the NOAA WP-3D Hurricane
Reconnaissance Aircraft
Ivan PopStefanija 1 , Edward J. Walsh 2
(popstefanija@prosensing.com)
1 ProSensing, Amherst, MA; 2 NOAA/ESRL/PSD, Boulder, CO
This JHT project focuses on developing the processing algorithms and real-time software needed
to perform in-flight data processing for the newly-developed Wide Swath Radar Altimeter
(WSRA). The WSRA is a novel digital beamforming radar altimeter developed with funding
from the NOAA SBIR program, with additional support from the University of Massachusetts
and DARPA.
In March of 2010, we had a partially-successful test flight. It was only a partial success because
the WSRA's power amplifier worked only intermittently during the flight. The WSRA hardware
was fixed by June 2010. Throughout the summer of 2010, ProSensing engineers worked on the
implementation of the real-time processing code for the unattended operation of the WSRA
system. This effort included optimization of the WSRA digital beamforming and range centroid
tracking algorithms, conversion of the processing algorithms into a multi-threaded C application,
and deployment of a multi-core PC processor to execute in-flight processing. In the new code we
also implemented several WSRA algorithm improvements: (1) antenna beam pointing angle
adjustment factor calculated based on the estimation of the antenna array width distortion caused
by the lateral movement of the aircraft during the data integration time (2) incremental (looped)
estimation of the range-to-surface in each beam weighed by the range estimates in the
neighbouring beams, (3) automatic adjustment of the WSRA radar parameters as the auxiliaryreported
aircraft’s altitude changes, (4) streamlining and automating the backend processing
which estimates the ocean wave directional spectra from the surface elevations, and (5)
developing the script that would format the data products and transmit in-flight the WSRA
output data file from the aircraft to the archiving and displaying computers at AOC in Tampa and
NHC in Miami. Upon completion of the software development, the WSRA was shipped to AOC
for the installation on WP-3D.
The WSRA was installed on the WP-3D aircraft mid-September, thereby missing the opportunity
to fly on several reconnaissance flights in hurricane Earl. For the rest of the season the WSRA
operated during one flight into a tropical disturbance south of Haiti and one reconnaissance flight
into CAT-1 hurricane Karl. The second half of the hurricane season did not provide any
additional opportunities to operate WSRA. All parts of the WSRA software were successfully
tested, including the transmitting of the data to AOC. Software and hardware performance during
flights have shown the feasibility of a fully-automated unattended operational WSRA. The two
flights we’ve conducted illuminated some problems in the WSRA code which have been since
corrected and tested. Currently, the WSRA is at AOC ready for operation during the 2011
hurricane season.
Session 3 – Page 5