Category Archives: Misc

AIP : the hangover

Yesterday, we held our antenna install party.

Don’t be confused: it was not a party according to the common standard where food, drinks and dance are required. Nothing of that sort: only antennas, coaxial cables and spectrum analysers. But we had fun and that makes it a pretty good party.

Still, I feel a sort of hangover considering that we did not manage to receive properly TV programmes.

There are two reasons for that: first, we have to find a better spot for our test sessions, one that is providing full line of sight. The second reason could be summarized as “RTFM” …

To conclude: we managed to make the antenna aquire the right satellite, but the signal was somewhat 10 dB short of power in order to be demodulated. Maybe an issue with the LoS which was … borderline to say the least (more line of sigh than line of sight from an antenna standpoint).

Thank you to Joan V-J., Pierre G. and Yannick D. – former students from SCS – who were my party mates for that nice evening.

Another AIP – second take – will be scheduled soon.

And now a couple of pictures (courtesy from Yannick D.)

The best spot we found to ensure line of sight ... to be improved
The best spot we found to ensure line of sight … to be improved
Our mobile "test rack"
Our mobile “test rack”

Antenna install party

We have received our new toy : an auto-pointing antenna from AVL (many thanks to Com-Ip for offering us a good deal).

Here is a picture of the antenna being deployed in the lab.

AVL auto-pointing antenna
The AVL auto-pointing antenna

In order to celebrate this event, we have scheduled an “Antenna Install Party” on Tuesday April 15, 2014 at 19:00. This will be the opportunity to test the antenna outside and assess the auto-pointing capabilities.

The meeting place is at the Télécom Bretagne Lab. If you want to join in, drop me a line (this is Laurent speaking). Note that there will be a  confirmation depending on weather conditions.

Looking forward meeting you there.

[Update as of Sun, April 13: the weather forecast tells “all sun” on Tuesday, so the install party is confirmed]

DVB-S2X is out !

The next generation standard for satellite broadcasting  is now ready to be released.

DVB-S2 is dead, long live to DVB-S2X.

What does it mean exactly ? Compared to DVB-S, S2 was paving the way to efficient spectral usage and agility with respect to channel conditions. DVB-S2X is hurtling down this road. Filter roll-offs can go down to 5%, the palette of MODCODs to choose from is now extended to cope with a wide variety of combinations between the terminal environment and the channel conditions.

See NewTec’s white paper for further information.

 

Emulating satellite transmission

We’d love to have actual satellite capacity at hand for the students projects but right now, it’s not yet available (we’re working on it !).

Emulation is the answer. It consists in reproducing in-lab the characteristics of a real system … without having to deploy the system itself. We’ve applied this clever concept to satellite transmission.

Here is a short video describing how we did it.

This was presented during the NI Days’14 morning keynote in Paris last February.

HTS is what we are all looking for

HTS stands for high-throughput satellite. (Almost) everybody knows that. But what is behind the scene exactly ? Lorenz G., one of our former student points us to this interesting tutorial from Intelsat.

Learn about the Ka-band, multi-spot beam systems and frequency reuse. Besides, you’ll also signifcantly enhance your private collection of space related acronyms !

Thank you !

Since the launch of this web site, we received a lot of support from our former students through the LinkedIn Alumni group. So I wanted to say “Thank you” on behalf of the academic staff here, it is much appreciated. We’ll get you posted with more articles as the project #1 season is nearing to its end. We’ll have interesting topics to talk about.

Another “Thank you” to Yannick D. (through Tetraneutral.net) and Mercator Ocean who donated some hardware for our lab. A helpful hand, indeed.

To conclude, let us wish you all a happy Christmas break.

In SDR we trust !

Software Defined Radio (SDR for short) is a new approach to design and deploy communication systems. It basically boils down to implement in software functions that are commonly found on ASICs (Application Specific Integrated Circuit). This is made possibly thanks for the ever-growing power of today’s CPU and also to the increasing popularity of FPGA (Field Programmable Gate Arrays).

In the SCS Programme, we believe that SDR is an important technology for space communications. Our experimental lab is equipped with cutting edge SDR technology such as the Vector Signal Transceiver from National Instruments. Another example is our “all digital”  low earth orbit satellite Earth station that has been designed by students and faculty staff. Thanks to its SDR-based weather receiver, we observe in real-time weather conditions when NOAA POES satellites such as NOAA-18 fly over Europe.

So yes, in SDR we trust !

NOAA18 flying over Europe (southbound) on the 19th of September, 2013
NOAA18 flying over Europe (southbound) on the 19th of September, 2013. Reception, demodulation and image decoding done on a NI USRP 2920 + LabView. Still some margin for improvement on the decoding side.