Whether guiding motorists from point A to point B or monitoring climate change, GPS and remote sensing technology have come a long way in the last few decades. Four IEEE Fellows from this year’s class have made significant contributions to improving the technologies and expanding their applications.
A TURNING POINT FOR GPS
Many of us would literally be lost if it weren’t for the work of entrepreneur Sanjai Kohli, who was elevated to Fellow this year for “leadership in developing receivers for consumer global positioning systems.” Kohli’s work on GPS chipsets has led to faster and more accurate navigation systems.
In the early 1990s, the GPS technology that had been used to guide ships and airplanes began popping up in automobiles in the form of expensive, yet slow, navigation devices. At the time, Kohli was president and chief technology officer of Software Technology & Systems, a company that developed smart munitions and spread-spectrum communications for the U.S. Department of Defense. While driving around the streets of Tokyo, he observed that it took his GPS device from 10 seconds to a full minute to find a satellite signal and indicate where to turn next. The device performed the worst in cities with tall buildings, which obstructed its link to GPS satellites.
Kohli and colleague Steven Chen designed a silicon chip that was three times faster than what was then available, and for a fraction of the price. The chip enabled a GPS device to pick up even the weakest satellite signal and process it within milliseconds.
In 1995 Kohli cofounded SiRF Technology, in San Jose, to manufacture and commercialize a range of GPS chipsets and software for consumer navigation systems. By 2006, 80 percent of all commercial GPS devices as well contained SiRF chips. He was the company’s chief technology officer until 2008, when it was acquired by Cambridge Silicon Radio (CSR) of England. Kohli is not retired but lists himself on LinkedIn as an “entrepreneur digging around for the next big opportunity.”
Malcolm Heron spent much of his career using radar to investigate conditions and phenomena that occur along and beneath the ocean’s surface. He was elevated to Fellow this year for “contributions to the application of radio science to oceanic and terrestrial remote sensing.”
Heron was founder and director of the Maritime Geophysical Laboratory at James Cook University, in Townsville, Australia, until he retired last year. In the early 1980s, he helped build a phased-array ocean-mapping radar at the university—one of the first civilian ocean radar systems in the world. The portable Coastal Ocean Surface radar (COSRAD) system was used to study the effects of climate change on the Great Barrier Reef, the world’s largest coral reef system, located off the coast of Queensland, Australia.
Until his retirement, Heron also served as lead scientist and director of the Australian Coastal Ocean Radar Network, where he spearheaded a project in 2009 to install high-frequency radar at several locations around the Australian coast. The radar has a wide range of applications, including monitoring the spread of pollution and detecting tsunami signatures, which are visible glowing ripples in the ionosphere above a site where a tsunami has struck or is about to strike.
UP IN THE CLOUDS
To what degree is our climate changing, and why? Clouds might hold part of the answer, according to Stephen Durden, a radar engineer at NASA’s Jet Propulsion Laboratory (JPL), in Pasadena, Calif. He was elevated to Fellow for “contributions to microwave remote sensing and radar systems, including spaceborne cloud radar.”
Durden has worked on modeling and analysis of radar data at JPL since 1986. He is the lead systems engineer for CloudSat, a satellite that studies clouds and precipitation from space using radar. Launched in 2006, CloudSat monitors conditions with millimeter-wave radar that is about 1000 times more sensitive than usual weather radar systems.
Because clouds and aerosols (fine suspended particles) reflect, absorb, and emit radiation, they play major roles in regulating Earth’s temperature. Until recently, scientists found it difficult to simulate the way that clouds and aerosols evolve as they interact with each other and respond to factors such as temperature, relative humidity, and air currents. But detailed data from CloudSat and other satellites around the world have shed light on the roles that clouds and aerosols might play in triggering major African droughts, altering Arctic climate, and weakening monsoons in southern Asia.
While Durden has an eye toward the sky, another new Fellow, Simonetta Paloscia, uses remote sensing technology to study land surfaces, vegetation, and soil. She was cited for “contributions to active and passive microwave remote sensing of vegetation and land surfaces.”
Paloscia is a senior scientist and leader of the microwave remote sensing group at the Institute of Applied Physics, in Florence, Italy. She has conducted pioneering research in the use of satellites equipped with microwave remote sensing technology to observe Europe’s water supply, agriculture, and forestry.
In 2006 she helped develop an algorithm for generating maps of soil moisture, snow depth, and vegetation with data from the Advanced Microwave Scanning Radiometer, a sensor aboard Aqua, NASA’s Earth observation satellite. The research aims to help scientists better understand, monitor, and manage agriculture on a global scale.
This year 329 senior IEEE members were elevated to the status of IEEE Fellow. In any given year, the rules permit no more than one-tenth of one percent of IEEE voting members to qualify for such elevation. For the entire list of new IEEE Fellows, and information on nominating a colleague, read “Introducing the 2012 Fellows” [The Institute, March].