Hello Jiri/Max, It appears that tracking by GSM is different in different areas, due to the GSM cover. One way to check this by testing GSM phones in the air. In Sweden, in urban areas, it seems that the phones can be used up to 500 m/AGL, in low-density areas it can work at higher altitudes. In mountainous areas the covering seems to be better. In general, GSM is not reliable for tracking glider flights as the GSM cover is designed for ground operations. Ake Pettersson
-----Ursprungligt meddelande----- Från: Max Kellermann [mailto:m...@duempel.org] Skickat: den 11 april 2013 08:54 Till: Ji??í P??lucha Kopia: xcsoar-user@lists.sourceforge.net Ämne: Re: [Xcsoar-user] Online tracking - skyline On 2013/04/11 08:47, Ji??í P??lucha <jiripelu...@gmail.com> wrote: > Dear Skylines tracking developers, > > I found your web page about online tracking and solutions at > http://www.skylines-project.org/about and I want to ask you, if you > could give me more information about it. > > We run small gliding competition in middle Europe, Czech Republic. > Last year we have for the first time new type of contest: grand prix. > We used online tracking throw airband tracker units. We had only > 1minutes fix updates because of capacity of frequency. > > I want to as you, how works your tracking? How do you send data to the > ground? Do you use GPRS connections or satellite connections? We do > research how we could develop tracking in our region and for example > satellite connection works, but its very expensive. Like you have in > your web page, for one flight you have to sent about 340kB. If we use > for example Iridium satellite chip, the cost for one kB is about 1-1,5USD. > > Thanks for your answers about tracking connections. Hi Jiri, unlike other tracking protocols, ours is based on small UDP packets of only 48 bytes, and no reply/acknowledge is received from the server. That makes the protocol very economic and very reliable. You can do your own math and check how much internet traffic is necessary for a certain update rate at 48 bytes for each update. I run SkyLines traffic at 5 seconds, but with Iridium you may want to have longer periods. XCSoar uses whatever IP connection is available. Usually, that is GSM / GPRS / UMTS. I have never heard of somebody using a satellite connection for SkyLines, but if Iridium provides IP access, that will work. It is suprising how well tracking works over (earth-bound) mobile networks. It is far from perfect, but works better than expected. Check the live tracks on a good day on our website. In any case, our protocol is open and documented, and even if you don't want to use XCSoar (or Gaggle), you can do your own implementation. This is the description of the protocol: http://git.xcsoar.org/cgit/master/xcsoar.git/tree/src/Tracking/SkyLines/Prot ocol.hpp Max ---------------------------------------------------------------------------- -- Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ Xcsoar-user mailing list Xcsoar-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xcsoar-user ------------------------------------------------------------------------------ Precog is a next-generation analytics platform capable of advanced analytics on semi-structured data. The platform includes APIs for building apps and a phenomenal toolset for data science. Developers can use our toolset for easy data analysis & visualization. Get a free account! http://www2.precog.com/precogplatform/slashdotnewsletter _______________________________________________ Xcsoar-user mailing list Xcsoar-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/xcsoar-user
