Geodesy is the scientific discipline that deals with the measurement of the Earth. One of the measurement techniques it employs uses radio waves from far-distant objects in space to determine factors such as the movement of tectonic plates. A high frequency amplifier promises to boost the performance of the radio telescopes this method requires.
Together with their Spanish colleagues from the Instituto Geográfico Nacional and the University of Cantabria, researchers from the Fraunhofer Institute for Applied Solid State Physics IAF in Freiburg have developed a very sensitive high frequency amplifier for radio telescopes used on Earth.
The amplifier generates extremely little internal electromagnetic noise and will help measure our planet from space more precisely than ever before. The position of radio telescopes will be pinpointed with a precision to approximately one millimeter – a tenfold improvement in accuracy.
The measurement technique relies on radio telescopes picking up radio waves emitted by objects in space; the more accurately scientists can determine the positions of the radio telescopes, the more precisely they can measure various characteristics of the Earth.
“Because the radio telescopes are placed far apart at sites all round the world, they detect the radio waves at different times,” explains Dr. Mikko Kotiranta, a researcher at Fraunhofer IAF. Determining the exact distances between telescopes becomes a matter of the accuracy with which these time lapses can be measured – a process in which every picosecond, or trillionth of a second, counts.
Combining several of these measurements allows scientists to determine with the greatest accuracy variables such as the length of day and the movement of tectonic plates, poles and the Earth’s axis. “This information is useful for a number of applications, for instance determining satellites’ orbits with greater precision,” says Kotiranta.
The radio waves in question come from quasars, which are supermassive black holes at the center of galaxies billions of light years away from Earth. As with any other celestial object, quasars are constantly moving through space, but they are so far away from Earth that from our perspective they appear to stand still. We also see them as a point-like objects, which makes them ideal fixed points of reference for measuring the Earth.
By the time the radio waves are picked up by the radio telescopes, however, the signal is extremely weak. This is because of the enormous distance they have had to travel through space. Another obstruction to obtaining a clear signal detection is the interfering electromagnetic noise generated by all bodies at temperatures above absolute zero – 0 Kelvin or minus 273 degrees Celsius.
From an electromagnetic perspective, absolute zero would be the temperature required for total silence. “The general rule is that the colder it is, the less noise is generated,” says Kotiranta.
A low-noise amplifier that works in the freezing cold
To address this problem, the researchers took a previous model of the amplifier and put it in an extra-cold freezer at a temperature of 22 Kelvin, or minus 251 degrees Celsius. Extreme conditions that exceed the capacities of electronic components. Or perhaps not?
To find out, the researchers at Fraunhofer IAF developed a mathematical model that describes how radio frequency circuits should be designed if they are to function at extremely low temperatures. Teaming up with their project partners, the researchersdeveloped a microwave amplifier in the cleanroom and the laboratory, which was then tested at different temperatures.
They used the results to refine the model so that its forecasts corresponded more closely with the recorded data. This updated model provided the basis for a new amplifier prototype, which the researchers continued to refine until they finally succeeded in developing a low-noise amplifier that fulfilled all the necessary requirements: an amplifier that works perfectly even at extremely low temperatures and the interfering electromagnetic noise of which was minimized.
This technology is currently in use in a newly constructed radio telescope belonging to the Instituto Geográfico National in Yebes in Spain. “Initial trials are already being conducted,” says Kotiranta. The project partners plan to start using the radio telescope for geodesy purposes from September onwards, for instance to measure the movement of tectonic plates.
Three more large radio telescopes – each with a diameter of over 13 meters – are currently being constructed. These telescopes will be built in the Azores and the Canary Islands, and are due to enter service by the end of 2015 and 2016 respectively. The four new telescopes will form part of the worldwide network of radio telescopes known as VGOS (Very Long Baseline Interferometry 2010 Global Observing System).
“Most telescopes date back to the 1970s and 1980s, and their technology is no longer state of the art. The new generation of telescopes will offer considerably more performance and provide us with information about our planet that is more accurate than ever before,” finishes Kotiranta.
Britta Widmann | Fraunhofer Research News
Data storage using individual molecules
17.12.2018 | Universität Basel
Formed to Meet Customers’ Needs – New Laser Beams for Glass Processing
17.12.2018 | Fraunhofer-Institut für Lasertechnik ILT
Researchers from the University of Basel have reported a new method that allows the physical state of just a few atoms or molecules within a network to be controlled. It is based on the spontaneous self-organization of molecules into extensive networks with pores about one nanometer in size. In the journal ‘small’, the physicists reported on their investigations, which could be of particular importance for the development of new storage devices.
Around the world, researchers are attempting to shrink data storage devices to achieve as large a storage capacity in as small a space as possible. In almost...
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
17.12.2018 | Physics and Astronomy
17.12.2018 | Architecture and Construction
17.12.2018 | Life Sciences