Sensors/Data Acquisition

Precision Detector Conductance Definition via Ballistic Thermal Transport

This innovation could be applied in the development of bolometric detector array sensors. Goddard Space Flight Center, Greenbelt, Maryland The characteristics of a thermal detector, such as sensitivity, response time, and saturation power (or energy resolution), are functions of the thermal conductance of the detector to its cryogenic environment. The thermal conductance is specified to achieve a tradeoff among the highest sensitivity, allowed response time, and the desired saturation energy or power budget for the particular application. It is essential to achieve the design thermal conductance (within an acceptable variance) after a thermal detector has been fabricated. Otherwise, the detector will fail to achieve its desired functionality. In addition, the formation of a multi-pixel imaging array becomes difficult and costly when the design thermal conductance is not achieved with high post-fabrication yield.

Posted in: Briefs, TSP, Sensors

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RF & MW Control Products in Silicon

Analog Devices’ new RF and microwave (MW) switch and attenuator products implemented in advanced silicon process benefit inherent advantages of silicon technology compared to legacy counterparts using gallium-arsenide (GaAs). This paper provides highlights on features and key performance parameters of the new switch and attenuator products.

Posted in: White Papers, Data Acquisition, Sensors

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Improved Ground Collision Avoidance System for General Aviation Aircraft and UAVs

This advanced warning system uses cutting-edge fighter jet technology to prevent controlled flight into terrain, which is a leading cause of aviation fatalities. Armstrong Flight Research Center, Edwards, California Controlled flight into terrain (CFIT) causes almost 100 deaths each year in the United States. Although warning systems have virtually eliminated CFIT for large commercial air carriers, the problem still remains for general aviation aircraft and unmanned aerial vehicles (UAVs). Existing systems are forced to rely on digital maps with low resolution/fidelity. They also require expensive equipment, limit the maneuvers to avoid collision, and frequently issue false alarms, causing pilots to ignore the safety system.

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Programmable Linear Position Sensors Leverage Inductive Technology

Benefits include maximizing noise rejection, compensating for mounting position without moving the sensor, error detection, and eliminating the need for a programmable process monitor. Novotechnik, Southborough, Massachusetts New technology combines the benefits of non-contact linear position sensing with the programmability of a programmable controller in a relatively small sensor package. This technology can help engineers in applications including those where costs and/or development time can be saved with all necessary control functions handled by the position sensor, applications requiring high accuracy over a small distance, and applications with high vibration or noisy environments. Practical applications include material handling equipment, crimping machines, and position sensors for linear actuators.

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Polarizing Sun Sensor

Commercial applications include agricultural, surveyor equipment, and energy conservation equipment installation. NASA’s Jet Propulsion Laboratory, Pasadena, California For a number of applications, the pointing direction towards the Sun must be known or measured. Con ventional Sun sensors determine the pointing direction towards the Sun while the Sun is in the field of view of the sensor. The disadvantage of a conventional Sun sensor is that it only operates when there is an unobstructed line of sight to the Sun. At some locations/seasons, it is virtually impossible to use a conventional Sun sensor.

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Three-Axis Sun Sensor for Attitude Determination

This three-axis attitude determination sensor is based on Sun observations. NASA’s Jet Propulsion Laboratory, Pasadena, California A conventional Sun sensor determines the orientation of the Sun in two axes. If mounted on Earth in a known coordinate system, it can determine the azimuth and elevation of the Sun. When mounted on a spacecraft, it can determine the pointing direction toward the Sun. Traditionally, Sun sensors have been based on optical/detector configurations that would change the magnitude of an electrical signal based on the angular incidence of the Sun (analog Sun sensor). Other types of Sun sensors have relied on optics and a geometric pattern placed over the detectors that generated an on/off (digital) signal depending on the solar angle (digital Sun sensor).

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Venus Heat Flux Sensor

NASA’s Jet Propulsion Laboratory, Pasadena, California A sensor element that consists of a thermally resistive layer made of nand p-type semiconductor elements amplifies the temperature gradient in the resistive layer that results from heat flow through the sensor. The thermoelectric array provides greater accuracy and sensitivity over a traditional thermopile arrangement for heat flux measurement. The thermoelectric sensor array is an adaptation of technology developed for generating electricity in radioisotope thermoelectric generators that operate with internal temperatures in excess of those at Venus. The technology is used in a different manner in that, instead of generating electrical power, it measures heat flow using a temperature differential output and a voltage output.

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