Our SONAR "Sisters": MISSy and CASSy

In 2016 we started with our real-time SONAR signal processing approaches. In a first work package we implemented the basic algorithms in our framework KiRAT. The underwater channel was simulated using linear and time-invariant (LTI) filters or we used prerecored signals. While the first approach (LTI simulation) is not very realistic, the second one does not allow to have our systems really in the "loop". Thus, the idea was born that our real-time approaches must be tested in real environments.

"Real environments" means here to test our systems in the Baltic sea. If we would try to get some measurement slots on research vessels (something what we will definetly do, but in addition to the following), the time between algrorithmic development and realistic testing would be much too long. Thus, we decided to built two small research ships that can be easily moved to different test places (ships on trailers). The first one should be really light weighted, such that a few of us can carry it without the need of any crane. The platform for this ship was a pedal boat from the US that we modified such that our MIMO-SONAR system can be used. This was also the origin for the ships name that Alexej Namenes created: MISSy, which stands for "MIMO SONAR system".

MISSy can carry either two people plus some light equimpement such as the underwater phone system or pseudo targets or one operator plus some more equipment. However, for our larger MIMO systems and especially if we would like to test distributed systems a second ship is necessary. Here, we decided to use a small ponton ship, with a small crane on it, that can be used for our cognitive adaptive SONAR systems, which is also the origin of the name "CASSy".

Both "sisters" together, MISSy and CASSy, will allow us to have really fast loops between system design with corresponding extensions and first water tests.


At best weather conditions we christened MISSy at the Kitzeberger beach. Even if we did not crash the bottle at MISSy's body, it was a very nice event. Besides the party, we also did the first test of our unterwater telephone system. We tested distances from just a few meters up to about 200 m. Full-duplex communication (both partners can speak and hear simultaneously) was possible. Very well done, Owe!

Today we tested a few new extensions for MISSy at the Mönkeberger beach. First of all, MISSy geta a new gearing unit. Our first attemts with a rudder in front of the screw were not very sucessful. The new way of controlling MISSy is much better. However, after a few minutes we had some material problems. One further iteration is necessary here. Furthermore, we tested the GPS unit - everything works as expected. Also our new equipment boxes did a good job - next time we will fill them with equipment.

After the winter break, the SONAR Ph.D. students, Alexej Namenas, Thorben Kaak, and Owe Wisch started to prepare MISSy for the upcoming measurement period. In a first, shot a plan for the necessary equipment was made and Owe started to put electricity on MISSy. Also two of the seats were removed and an aluminum platform, that should carry everything, was started. The idea here is that the new platform should be lighter compared to the original one.

Today Alexej Namenas collected MISSys trailer. Alexej also desigend MISSy's logo and the new DSS-SONAR logo. Now, we are really prepared for moving MISSy to the places we would like to do measurements with her. In addition, her new "house" protects her and the corresponding additional equipment during winter.

Meanwhile the extensions on our trailer, that allow us to move MISSy to various water places, are ready. Thanks again to Matthias Burmesiter and his team for their help here. This allows us to do a very first test on the water with MISSy.

Since MISSy is a pedal boat right now, we are MISSy "engine" for the test. It is planned to have to two people plus equipment on MISSy during our tests. In order to see if this is possible three of us are on MISSy for the test (one is "simulating" the equipment). Finally, everything works and we had a lot of fun on the cold November water. Let's go now for the next steps.


Shortly after the trailer also the "Skeleton" of MISSy arrived in Kiel. After clearing all customs issues we are very happy to have now the most important "incredients" for MISSy at the faculty. In the afternoon, we already started with putting all parts together and began with the construction of the "extras" that we need for our SONAR systems.


After some preparation we had the first water test with CASSy. First of all, thanks for the help from the Bundeswehr (Dr. Arne Stoltenberg and Dr. Jan Abshagen). After some engine problems that could be fixed really quickly, we had our first trip in the Baltic sea (from Kiel to Mönkeberg and back). Everything worked fine ... as a next step, we will have a test with SONAR equipment on bord.

Today CASSy arrived in Kiel. Thorben, Alexej and Owe went to Wismar and "pulled" her to the Technical Fakulty. Now, we can start to prepare here for our new MIMO-SONAR system as well as for your new communication hardware.

Today we got good news for CASSy. Our DFG proposal for a new SONAR system with CASSy being part of it was approved. This means, that MISSy will now really get CASSy as a "sister". After the vacation period we will start to order all necessary parts. Step by step we come closer to our goals ...

In November 2017 we finished our first "DFG-Großgeräteantrag" with CASSy as a part of it. At this time we recognized that MISSy is too light for larger SONAR equipment and that we need a slightly larger "sister" for MISSy. Thus, we discussed how CASSy could look like and what features and properties are required. Finally, we added CASSy to the proposal. Now, we keep our fingers crossed to get the approval for CASSy.


Prof. Dr.-Ing. Gerhard Schmidt

E-Mail: gus@tf.uni-kiel.de

Christian-Albrechts-Universität zu Kiel
Faculty of Engineering
Institute for Electrical Engineering and Information Engineering
Digital Signal Processing and System Theory

Kaiserstr. 2
24143 Kiel, Germany

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Recent News


Recently, we get the new projector front-ends from Atlas Elektronik for our MIMO SONAR system. This was part of the "Großgerät" which was obtained with the help of the German research foundation (DFG). Now we are able to perform underwater experiments that will show if our ideas and corresponding realt-time algorithms also works in real environments.

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