Tuesday, May 19, 2009 at 4:30pm

(refreshments available at 4:00pm)

Place: Johns Hopkins University Applied Physics Laboratory

Featuring:

Abstract:The Lunar Mini-RF Radars and their Hybrid Polarimetric Architecture

The Mini-RF radar aboard India's Chandrayaan-1 satellite now at the Moon is the first polarimetric synthetic aperture radar (SAR) outside of Earth orbit. The architecture of this radar-and of its more advanced sibling on NASA's Lunar Reconnaissance Orbiter (LRO)-is hybrid dual-polarimetric, in which the transmitted field is circularly polarized, whereas the received orthogonal polarizations are linear. Classical Earth-based radar astronomy, being circularly polarized on both transmission and reception, provided the initial conditions for this new paradigm. The enabling innovation leading to hybrid polarity is recognition that the fundamental data product from a dual-polarimetric radar is a 2x2 covariance matrix, not just "imagery". The covariance matrix is sufficient to calculate the four-element Stokes vector of the observed field; the values of the Stokes parameters are invariant with respect to the observation polarization basis of the backscatter. It follows that the radar architecture may be optimized with respect to engineering principles, without impacting science, hence hybrid polarimetry. It follows that the Mini-RF radars offer the same suite of polarimetric information from lunar orbit as state-of-the-art radar astronomy, most elegantly illustrated by the Arecibo-Green Bank combination. The most prominent advantages of hybrid polarimetric architecture include self-calibration, and simpler flight hardware. The technique may be generalized to full (or quadrature) polarimetric SARs as illustrated by the baseline design of JPL's DESDynI radar. Hybrid quad-pol architecture has many advantages over conventional linearly-polarized designs, especially significant suppression of range ambiguities, which are the dominant limiting factor on orbital quad-pol radars. Salient features of the hybrid dual-polarized SAR architecture will be illustrated with Mini-RF examples.

Abstract:Remote Sensing in the JHU/APL Space Research Branch

The Space Research Branch of APL has satellites, sensors, and research projects that span the solar system from the Sun to Pluto. To meet these research needs, the branch is divided into groups specializing in Earth remote sensing, planetary physics, upper atmospheric physics, and heliospheric work. Remote sensing, a common theme across these groups at APL, will be summarized, including radar measurements from Earth orbit, from orbit around Venus, the moons of Jupiter, and in lunar orbit. UV, visible and IR measurements are made in orbit around Mars to determine Martian geometry, around asteroids, and in Earth orbit to measure a variety of factors including ocean color, atmospheric constituents, and ionospheric emissions. In the past two decades, the bulk of APL's remote sensing activities, in terms of both dollars and people, have been outside of the Earth. Given recently awakening awareness of global climate change and the need for improved monitoring of Earth processes, there is an increasing emphasis on Earth Science. APL plans to leverage its well-established remote sensing research capabilities to address issues raised by the National Research Council's Earth Science Decadal Survey.

Biosketch: Dr. R. Keith Raney
Dr. R. Keith Raney received a BS (with honors) in physics from Harvard University (1960), a MSEE from Purdue University (1962), and a PhD in Computer Information and Control from the University of Michigan (1968). He contributed to the design of NASA's Venus radars Pioneer and Magellan, the ERS-1 microwave AMI instrument of the European Space Agency (ESA), and the Shuttle Imaging Radar SIR-C. He was on NASA's Instrument Definition Teams for the Europa Orbiter and several Mars missions. While with the Canada Centre for Remote Sensing (1976-1994) Dr. Raney was scientific authority for the world's first digital processor for the SeaSat synthetic aperture radar (SAR), and responsible for the conceptual design of the RADARSAT SAR. Presently he is on the Science Advisory Group for ESA's CryoSat radar altimeter, whose design is based on his original concept, and he is the design architect for the Mini-RF hybrid-polarity radars on India's Chandrayaan-1 and NASA's Lunar Reconnaissance Orbiter. These and other contributions in radar remote sensing systems, theory, and applications are documented in more than 300 professional publications.

Dr. Raney holds several United States and international patents on various aspects of radar. He is a past president (1988, 1989) of the IEEE Geoscience and Remote Sensing Society, and for more than 20 years was an Associate Editor (radar) for the Society's Transactions. He has served on numerous advisory committees for domestic and international organizations, including the Office of Naval Research, the National Academy of Sciences, the European Space Agency, Germany's Helmholtz Society, and the Danish Technical Research Council, among others. He is a Life Fellow of the IEEE, a Fellow of the Electromagnetics Academy, and an Associate Fellow of the Canadian Aeronautics and Space Institute. Dr. Raney is a recipient of numerous awards, including the IEEE Geoscience and Remote Sensing Society 1993 Distinguished Achievement Award, the 1999 Gold Medal of the Canadian Remote Sensing Society, the IEEE Millennium Medal 2000, and the IEEE 2007 Dennis J. Picard Medal for radar technologies and applications.

Biosketch: Mr. Frank Monaldo
Mr. Frank Monaldo has been with the Johns Hopkins University Applied Physics Laboratory since 1977, following his graduation with a BA and MS summa cum laude in physics from the Catholic University of America. He currently is a Principal Staff Physicist and has supervised the Ocean Remote Sensing Group since 2005. His career has encompassed the theoretical development of optical and radar remote sensing techniques and the implementation and validation of these techniques. He has published extensively on error sources in radar altimetry measurements and the operational retrieval of wind and wave measurements from synthetic aperture radar.

Mr. Monaldo served on NASA's Science Working Group for the Shuttle-Imaging Radar (SIR-C) mission. He was a member of the JHU/APL group that designed and implemented a real-time SAR processor for the SIR-C mission that produced real-time estimates of SAR-derived ocean-wave spectra. He is the Principal Investigator for the JHU/APL portion of the Alaska SAR Demonstration Project sponsored by NOAA/NESDIS, which produces high-resolution real-time wind speed maps. In the next couple of years this project will be transitioned to an operational NOAA product. Mr. Monaldo is a member Phi Beta Kappa and the Blue Key Honor Societies, Institute of Electrical and Electronic Engineers, the American Geophysical Union, URSI Commission F, NASA's Spaceborne Imaging Radar (SIR-C) Science Team (competitive selection process), the Satellite Meteorology and Oceanography Committee of the American Meteorological Society (1999-2002), Alaska Satellite Facility Users Group, and Sigma Xi.