For the First Time, Researchers Use an Atom Interferometer to Measure Aircraft Acceleration

Atom Interferometry Explained Geiger et al. via arXiv

Atom interferometers are neat little devices that exploit the wave characters of atoms to make highly precise measurements of things like distance and or the force of gravity. But because they are fickle by nature--even the smallest vibrations distort their results--atom interferometers have been mostly limited to highly controlled experiments that take place in either underground labs or in free-falling zero-g experiments. But a team of French researchers has announced today the first use of an atom interferometer to measure the acceleration of an airplane.

This is useful because atom interferometers are super sensitive, more so than the inertial sensors used widely on modern aircraft. Those inertial sensors have been known to fail with potentially disastrous results, but more frequently they cause slight errors to creep into navigation systems that must later be corrected. With no moving parts and a high degree of accuracy, atom interferometers could mitigate these problems, recording inertial effects 300 times weaker than the normal fluctuations in the acceleration in a standard aircraft.

But the vibrations in an aircraft have previously made deployment of atom interferometers in planes unfeasible. That’s where Remi Geiger at the Laboratoire Charles Fabry in Paris comes in. He and his colleagues have created a system that compensates for the effects of vibrations via mechanical accelerometers that record the movements of the aircraft itself.

Using that vibration data, their system recalculates the interferometer’s data to compensate for any vibration that might be skewing its final result. By stripping out the vibration noise, they end up with a clean, high-resolution atom interferometer result. The system could go a long way toward delivering better acceleration data to the cockpits of large jets. Geiger and company have already tested their system successfully on an Airbus A300.

But an atom interferometer that can operate free of laboratory constraints isn’t limited to jetliner applications. The researchers hope their method will lead to more precise measurements of geodesy and of gravity itself, enabling some fundamental experiments that have been previously very difficult to conduct and challenging some existing principles of physics with more and better data. More at arXiv.

[Technology]

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Miniature power plants for aircraft bodies

ScienceDaily (June 14, 2011) — Sensor networks are supposed to pervade the body shell of airplanes in the future -- much like a nervous system. Thanks to a joint research project of EADS Germany and the Vienna University of Technology, these sensors do not require any external power supply.

Aircraft maintenance can be time consuming and expensive. It is much simpler if the airplane itself reports, where maintenance is required. The best solution is a sensor system, which even has its own power supply and is therefore independent of electrical wiring -- and this is what has now been developed by EADS Germany, in cooperation with the Institute of Sensor and Actuator Systems at Vienna University of Technology (TU Vienna). For each individual sensor, electricity is produced by a thermoelectric generator with a small water tank, storing thermal energy. The electricity is simply generated from the temperature difference between the icy cold air in high altitudes and the air close to the ground. This new sensor technology could not only facilitate aircraft maintenance, but also increase comfort for travelers.

Energy from the "Energy Harvester Module"

Even small collisions can easily lead to damage in the body of the aircraft. On aluminum bodies, a slight dent may be visible -- but on modern carbon materials, it is much harder to detect damage. Tiny, invisible cracks may appear, which are very hard to detect. With suitable sensors connected directly to the body of the aircraft, this could be constantly monitored. "A major problem with these sensors is the energy supply. Wiring up hundreds of sensors in the aircraft body is complicated and expensive," professor Ulrich Schmid from the Institute for Sensor and Actuator Systems at TU Vienna explains. For this reason, he -- together with Dominik Samson and professor Thomas Becker (EADS Germany) -- developed the idea of the "thermoelectric energy harvester" as an energy source, in order to be completely independent of batteries and wiring.

Electrical Current from Differences in Temperature

When an airplane rises to an altitude of thousands of meters, the exterior wall cools down. "From the temperature difference between the exterior and the interior, we can harvest energy for the sensor element, using a thermoelectric generator," Dominik Samson explains. In the energy-harvester module, there is a little water tank which can store the ground temperature for a while. Water is especially well suited for this task, because it can store large quantities of energy in terms of heat. The inner part of the module with the water tank is connected to the cold exterior wall via the thermoelectric generator. Therefore, a gradient in temperature arises at the generator, which can be used to create electrical voltage. During landing, it works the other way around: The plane heats up again, whereas the inner part of the module is still cold -- and again, electricity can be produced.

Whenever there is no thermoelectric current, for instance right after takeoff and during the landing, sophisticated electronics controls storage and transfer of electrical energy. The electronics and the components which create electricity only take up very little space: They fit on the palm of a hand and can easily be integrated into the aircraft body. The size can be adjusted for the individual energy demand of different applications.

No Wires, no Batteries

The data collected by the sensor can be transmitted wirelessly. Wireless technology does not only make maintenance easier, it also minimizes potential causes of defect and it reduces the weight of the airplane. During one flight, the energy harvester can provide the energy of eight to ten milliwatt hours -- which is sufficient for a wireless sensor. "A plane has a durability of roughly thirty years. If the sensors were operated with batteries, each of them would use up about one hundred batteries during this time," Dominik Samson estimates. Using a large number of sensors, this would not only require costly maintenance but it would also create unnecessary amounts of waste.

The concept of generating electricity in the airplane by utilizing differences in temperature could also be used for other purposes. Sensors could monitor whether the passengers have fastened their seatbelts or whether the tables are in an upright position. At the push of a button, a wireless signal could be transmitted to the flight attendants -- without expensive and complicated wiring, just powered by the body heat of the passengers. "The first and most important step has been taken. We are confident that this wireless sensor technology will travel on board of many airplanes soon," Ulrich Schmid says.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Vienna University of Technology, TU Vienna, via AlphaGalileo.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Miniature power plants for aircraft bodies

ScienceDaily (June 14, 2011) — Sensor networks are supposed to pervade the body shell of airplanes in the future -- much like a nervous system. Thanks to a joint research project of EADS Germany and the Vienna University of Technology, these sensors do not require any external power supply.

Aircraft maintenance can be time consuming and expensive. It is much simpler if the airplane itself reports, where maintenance is required. The best solution is a sensor system, which even has its own power supply and is therefore independent of electrical wiring -- and this is what has now been developed by EADS Germany, in cooperation with the Institute of Sensor and Actuator Systems at Vienna University of Technology (TU Vienna). For each individual sensor, electricity is produced by a thermoelectric generator with a small water tank, storing thermal energy. The electricity is simply generated from the temperature difference between the icy cold air in high altitudes and the air close to the ground. This new sensor technology could not only facilitate aircraft maintenance, but also increase comfort for travelers.

Energy from the "Energy Harvester Module"

Even small collisions can easily lead to damage in the body of the aircraft. On aluminum bodies, a slight dent may be visible -- but on modern carbon materials, it is much harder to detect damage. Tiny, invisible cracks may appear, which are very hard to detect. With suitable sensors connected directly to the body of the aircraft, this could be constantly monitored. "A major problem with these sensors is the energy supply. Wiring up hundreds of sensors in the aircraft body is complicated and expensive," professor Ulrich Schmid from the Institute for Sensor and Actuator Systems at TU Vienna explains. For this reason, he -- together with Dominik Samson and professor Thomas Becker (EADS Germany) -- developed the idea of the "thermoelectric energy harvester" as an energy source, in order to be completely independent of batteries and wiring.

Electrical Current from Differences in Temperature

When an airplane rises to an altitude of thousands of meters, the exterior wall cools down. "From the temperature difference between the exterior and the interior, we can harvest energy for the sensor element, using a thermoelectric generator," Dominik Samson explains. In the energy-harvester module, there is a little water tank which can store the ground temperature for a while. Water is especially well suited for this task, because it can store large quantities of energy in terms of heat. The inner part of the module with the water tank is connected to the cold exterior wall via the thermoelectric generator. Therefore, a gradient in temperature arises at the generator, which can be used to create electrical voltage. During landing, it works the other way around: The plane heats up again, whereas the inner part of the module is still cold -- and again, electricity can be produced.

Whenever there is no thermoelectric current, for instance right after takeoff and during the landing, sophisticated electronics controls storage and transfer of electrical energy. The electronics and the components which create electricity only take up very little space: They fit on the palm of a hand and can easily be integrated into the aircraft body. The size can be adjusted for the individual energy demand of different applications.

No Wires, no Batteries

The data collected by the sensor can be transmitted wirelessly. Wireless technology does not only make maintenance easier, it also minimizes potential causes of defect and it reduces the weight of the airplane. During one flight, the energy harvester can provide the energy of eight to ten milliwatt hours -- which is sufficient for a wireless sensor. "A plane has a durability of roughly thirty years. If the sensors were operated with batteries, each of them would use up about one hundred batteries during this time," Dominik Samson estimates. Using a large number of sensors, this would not only require costly maintenance but it would also create unnecessary amounts of waste.

The concept of generating electricity in the airplane by utilizing differences in temperature could also be used for other purposes. Sensors could monitor whether the passengers have fastened their seatbelts or whether the tables are in an upright position. At the push of a button, a wireless signal could be transmitted to the flight attendants -- without expensive and complicated wiring, just powered by the body heat of the passengers. "The first and most important step has been taken. We are confident that this wireless sensor technology will travel on board of many airplanes soon," Ulrich Schmid says.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Vienna University of Technology, TU Vienna, via AlphaGalileo.

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Spotted: A Very Rutan-Looking Experimental Aircraft Cruising California Skies

An undeniably Burt Rutan-esque aircraft has been spotted in the airspace just a few dozen miles south of Beale Air Force Base, prompting aerospace buffs to post the question: what is this Burt Rutan-esque aircraft doing in the air near Beale Air Force Base? Flight Global has since identified (possibly) the plane as Scaled Composites Model 355, but what’s less clear is what sort of aircraft it might be.

The DEW Line’s Stephen Trimble ventures a guess:

I'm going to go out on a limb here and say the Model 355 is not just manned, but is probably optionally unmanned, too. And those antennas on the bottom of the fuselage are clearly not intended for civilian purposes. That is a signals intelligence payload, my friends.

Whoa. An optionally manned/unmanned medium-altitude, long-range experimental aircraft with a SIGINT package strapped to the belly? Consider us intrigued. The image above surfaced on Flickr a couple of weeks back, while the shot above was captured and posted by a photog near Beale yesterday (though this flightplan suggests if took off and landed via regional airports, so the AFB link is dubious). If more photos/information surface, we’ll update here.

The (Purportedly) Scaled Composites Model 355:  jw2513 via Flickr

[The DEW Line]

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