RF & Microwave Electronics

GPS Tide Gauge Measures Sea Level Change

Using radio signals from satellite navigation systems, Scientists at Chalmers Department of Earth and Space Sciences have developed and tested a Global Navigation Satellite System (GNSS) tide gauge, an instrument that measures the sea level.The GNSS tide gauge uses radio signals from satellites in orbit around the Earth that are part of satellite navigation systems like GPS and Glonass (Russia’s equivalent of GPS).Two antennas, covered by small white radomes, measure signals both directly from the satellites and signals reflected off the sea surface. By analyzing these signals together, the sea level and its variation can be measured, up to 20 times per second.”We measure the sea level using the same radio signals that mobile phones and cars use in their satellite navigation systems,” says researcher Johan Löfgren. “As the satellites pass over the sky, the instrument ‘sees’ their signals – both those that come direct and those that are reflected off the sea surface.” SourceAlso: Learn about Global Positioning System (GPS) Meteorology.

Posted in: Environmental Monitoring, Green Design & Manufacturing, Test & Measurement, Measuring Instruments, RF & Microwave Electronics, Antennas, News

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Unmanned Aircraft Tested as Tool for Measuring Polar Ice Sheets

Scientists studying the behavior of the world's ice sheets — and the future implications of ice sheet behavior for global sealevel rise — may soon have a new airborne tool that will allow radar measurements that previously would have been prohibitively expensive or difficult to carry out with manned aircraft.

Posted in: Environmental Monitoring, Green Design & Manufacturing, Test & Measurement, Measuring Instruments, Monitoring, Aerospace, Aviation, RF & Microwave Electronics, News

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Eliminate Risk of Contention and Data Corruption in RS-485 Communications

The RS-485 communications standard was introduced in 1983 by the Electronic Industries Alliance (EIA) as a two-wire, half-duplex, multi-drop alternative to the point-to-point RS-232 interface. (Note: RS-485 can also be wired using 4-wires to enable full-duplex communication). RS-485 uses differential signaling to allow up to 32 devices to communicate peer-to-peer at distances up to 4000 feet. In most RS-485 configurations two signals, a positive and a negative, are run as a twisted pair. Since these signals are compared to one another rather than a ground reference like RS-232, RS-485 communication is less susceptible to external noise injected on the wiring and performs more reliably in industrial environments.

Posted in: RF & Microwave Electronics, White Papers

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Remote Sensing Moisture Model Could Aid Farmers

Global farmers could get better decision-making help as refinements are made to North Alabama soil moisture modeling research being done by an atmospheric science doctoral student at The University of Alabama in Huntsville. The models indicate how much added moisture would be needed in a given area versus historical data to achieve various crop yields, and they could aid in making expensive infrastructure investments by helping to determine their economic viability.

Posted in: Sensors, Software, Mathematical/Scientific Software, RF & Microwave Electronics, News

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NASA Radar Demonstrates Ability to Predict Sinkholes

New analyses of NASA airborne radar data collected in 2012 reveal that radar detected indications of a huge sinkhole before it collapsed and forced evacuations in Louisiana that year. The findings suggest such radar data, if collected routinely from airborne systems or satellites, could at least in some cases foresee sinkholes before they happen, decreasing danger to people and property.

Posted in: Environmental Monitoring, Green Design & Manufacturing, Sensors, Test & Measurement, Monitoring, Aerospace, RF & Microwave Electronics, News

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NASA Model Provides 3-D View of L.A. Earthquake

On March 28, residents of Greater Los Angeles experienced the largest earthquake to strike the region since 2008. The magnitude 5.1 quake was centered near La Habra in northwestern Orange County about 21 miles (33 kilometers) east-southeast of Los Angeles, and was widely felt throughout Southern California. There have been hundreds of aftershocks, including one of magnitude 4.1.Scientists at NASA's Jet Propulsion Laboratory, Pasadena, Calif., have developed a model of the earthquake, based on the distribution of aftershocks and other seismic information from the U.S. Geological Survey.A new image based on the model shows what the earthquake may look like through the eyes of an interferometric synthetic aperture radar, such as NASA's Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR). JPL scientists plan to acquire UAVSAR data from the region of the March 28 quake, possibly as soon as this week, and process the data to validate and improve the results of their model. The UAVSAR flights serve as a baseline for pre-earthquake activity. As earthquakes occur during the course of this project, the team is measuring the deformation at the time of the earthquakes to determine the distribution of slip on the faults, and then monitoring longer-term motions after the earthquakes to learn more about fault zone properties. SourceAlso: Learn about QuakeSim 2.0.

Posted in: Imaging, Software, Mathematical/Scientific Software, Test & Measurement, Monitoring, RF & Microwave Electronics, News

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Wireless Device Senses Chemical Vapors

A research team at the Georgia Tech Research Institute (GTRI) has developed a small electronic sensing device that can alert users wirelessly to the presence of chemical vapors in the atmosphere. The technology, which could be manufactured using familiar aerosol-jet printing techniques, is aimed at myriad applications in military, commercial, environmental, and healthcare areas.The current design integrates nanotechnology and radio-frequency identification (RFID) capabilities into a small working prototype. An array of sensors uses carbon nanotubes and other nanomaterials to detect specific chemicals, while an RFID integrated circuit informs users about the presence and concentrations of those vapors at a safe distance wirelessly.Because it is based on programmable digital technology, the RFID component can provide greater security, reliability and range – and much smaller size – than earlier sensor designs based on non-programmable analog technology. The present GTRI prototype is 10 centimeters square, but further designs are expected to squeeze a multiple-sensor array and an RFID chip into a one-millimeter-square device printable on paper or on flexible, durable substrates such as liquid crystal polymer.SourceAlso: Learn about Extended-Range Passive RFID and Sensor Tags.

Posted in: Electronics & Computers, Electronic Components, Electronics, Manufacturing & Prototyping, Environmental Monitoring, Green Design & Manufacturing, Sensors, Detectors, Medical, Communications, Wireless, RF & Microwave Electronics, Semiconductors & ICs, Nanotechnology, Defense, News

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