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  • Reviving an old thread.

     But put cost aside, how hard is it to exchange the 3Dr telemetry with one of the iridium  SAT modems. 


  • SATCOM is unusable for most of us, but not because of latency. It is possible with some satellite companies to obtain the less than .5 milliseconds latency required for real time control, point to point, but it is a dedicated pipe, and very expensive (similar to MPLS). We did studies with a company called Segovia, who is one of the big dogs with access to 50% of over a dozen satellites about doing Combined VoIP and Data over Private networks between the US and Dubai and various other regions in the ME. It was doable for sure, but the price tag was amazing... If I had to guess today... you could most likely start out at around 10,000.00 USD/month, which may be possible with a very large organization, but then you would be limited to the number of members that could be connected at any one time.

  • thanx for all

  • @Tom 

    It's both, it can be used in Normal Mode ("Gateway mode"), which allow [near] real time messaging (if you consider upto 3min delay). That mode is very limited and only works in major markets (does not work in oceanic environments cause of the ground station problem). Note, the sats allow bi-directional comm and thus can relay data, but I have a feeling it's not offered at the consumer level (??).

    Of course, you link to orbcomm in Globalgram mode, which then messages are processed in store and forward fashion.


    Note OrbComm2 was approved with much improvement, and launches were started recently.

    If you need the service now, you may want this unit instead, though maybe a bit big.

  • Moderator

    Years ago, before the availability of fiberoptic networks across our province here in northern Alberta, brought high speed Internet, our college did extensive testing and found satellite to be unsuitable for multimedia of any kind.

    With the delay and "batching" of data, it would be likewise unsuitable for realtime control of R/C FPV, or UAV craft.

    Plus, just as @Tom mentioned, our antennae were the size of sat TV from the '80s!


  • If my memory serves me correctly from a study I did several years ago, Orbcomm is a store-and-froward satellite system.  When a satellite happens to pass overhead, you dump your data to it, it then will drop your data off at the next available ground station.  Great for non-real-time things like tracking a shipping container or getting data from a meteorological buoy in the middle of the ocean.  Not so hot for realtime command and control.  If you want a satellite modem for that you'll need to go Iridium or Globalstar (LEO) or some others that have sprung up in GEO, but require larger antennas. 

  • Nice catch Gary!

  • Moderator

    There is a portion of the sat band being allocated for dedicated UAS command and control, along with some lower frequencies as well. Do not expect RC type command and control frequencies to be allowed to do anything other than LOS stuff. Radio regulators around the world have not had to consider UAS usage for stuff they have licensed on the basis that its being used by enthusiasts for fun. I had to get a special licence for a JR radio in the UK for a thing, because OFCOM would not accept the standard one it comes with for hobby use. It was not difficult, but had to be done.

    Just one of the many elephants in the room, in fact an entire herd of them as we move towards wider acceptance.

  • Satellite communication is the holy grail.  Hopefully after Google buys out 3drobotics, sparkfun, & hobbyking, they'll get the RC broadband satellite launched.

    For now, we're stuck with Orbcomm.  According to kiwipedia, "gaps between satellites can result in message delivery times of 15 minutes or more...To avoid interference, terminals are not permitted to be active more than 1% of the time, and thus they may only execute a 450ms data burst twice every 15 minutes."

  • Haha good one Gary! :P

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