On the Back of the Birds

Published by Max Planck Institute on Mon, 09/14/2015 - 14:36
The drone as a bird – Prof. Andreas Knopp (l.) and  his research assistant Christian Hofmann use a  simulation to understand the distribution character- istics of signals in the best way possible

 

 

 

 

 The drone as a bird – Prof. Andreas Knopp (l.) and his research assistant Christian Hofmann use a simulation to understand the distribution characteristics of signals in the best way possible.


The research association “ICARUS” analyzes the migratory behavior of amongst others birds and bats in order to anticipate the spread of diseases and natural disasters – Prof. Andreas Knopp, Chair of Signal Processing, and his team provide the necessary know-how.

MRSA, SARS, bird flu – the list of rapidly spreading diseases is long. Also earthquakes and floods endanger human lives. In order to enable a timely reaction to these, the research association “ICARUS”, led by the renowned Constance-based Professor Martin Wikelski, Head of the Max Planck Institute for Ornithology in Radolfzell, now observes the migratory behavior of small animals such as birds, bats and insects from space. The group receives technical support from Professor Andreas Knopp and his team at the Bundeswehr University Munich. They take over a decisive role in the development of complex transmitting and measuring techniques for the project.

Professor Knopp and the research assistants Christian Hofmann and Robert Schwarz at the Institute for Information Technology at the Department of Electrical Engineering and Information Technology analyze the distribution characteristics of signals, which have to bridge a distance of 400 km from a mini transmitter on the back of the animals to the International Space Station. They investigate how the transmitter – adjusted to the low body weight between 1-5g – works with as little energy as possible and how it shows appropriate signal strength even if subjected to difficult weather conditions. Energy consumption is the decisive factor for the weight of the future transmitter and thus also determines which animals can be observed.

Contrary to the direct communication of an earth station with the International Space Station, the mini transmitter broadcasts its signal into different directions due to its little antenna. The signal will then be reflected by the ground as well as surrounding objects and overlaps with itself at its receiver within a time lag. This effect leads to specific, time-dependent attenuations of the signal, whose extent is determined by Professor Knopp and his team through measurements. The results are incorporated into the design of the planned ICARUS system, which will be installed onto the Russian module of the International Space Station in 2016. The project is headed by the Max Planck Institute for Ornithology.

Tiny transmitter, great potential

“The transmission power is the critical factor,” explains Professor Knopp. In a complex experimental setup, which amongst others uses a drone equipped with transmitting and measuring technique that simulates the bird and an airplane that simulates the overflight of the ISS, the research team attempts to understand the distribution characteristics of the signals in the best way possible. Together with the researchers of Max Planck, who contributed the airplane and with head Wikelski also the pilot themselves and gave instructions on the typical behavior of the birds, they carried out measurements in different places around Munich – from small to medium-sized villages such as Bayrischzell and Neubiberg through to regions characterized by water and mountain landscapes such as Lake Ammer and Lake Schlier

“Every environment has various effects on the signal. From the measurements and analyses we then develop a model, which can be used for the optimization of the transmitting system later. This is necessary in order to get the most out of the small battery in the transmitter,” adds Christian Hofmann. Within the future system the ISS will wake the mini transmitter from its energy-saving mode only for a short time, when it has visual contact to the bird on its flight. The transmitter on the back of the bird then sends a signal to the space station within a few seconds. The data volume of only a few 100 bits would not even be sufficient to send a text message. The signals contain important data about the body functions of the animal as well as its position and movements. This way the researchers of Max Planck want to use the senses of the animals, through which they are hoping to, for example, draw significant conclusions about impending natural disasters.

Simulation with the Bundeswehr satellite

Apart from its long-term experience in theory and practice the research team enriches the project in another special way: “We have been able to also carry out measurements via the communication satellites of the Bundeswehr and thus simulate the ISS. Today, the Bundeswehr is the only national satellite operator in Germany and is one of only a few nations, which has access to the necessary frequency band. Of course, in this case we benefit from the good cooperation with other Bundeswehr institutions – they support us in a quick and uncomplicated way, where the military main task allows for it. The Bundeswehr has excellent technical equipment that other institutions are short of. In particular within this project this was an invaluable asset, even for an otherwise excellently equipped research institution such as Max Planck,” emphasizes Professor Knopp.

Text Eva Olschewski. Translation: Melina Rosa Saur