====== GNSS ITxPT ======


In this example enable ITxPT on Netmodule NB2800 and receive a GPS position of the router via ITxPT implementation. As a client, we use a pc with linux-debian 11. 

Requirements: 
  * Netmodule Router with licensed ITxPT 
  * A client, in our case linux debian 11

  - Enable GPS in JSON mode. (Just enable GPS, Json mode is default)
  - Setting up GNSS ITxPT service on NB2800:

SERVICES -> ITxPT -> Configuration -> ITxPT Administratio enable.
Choose your LAN Interface, your client is connected to. In our case this is LAN1.
{{ :itxpt_enable.png?400 |}}

Goto Gnss Tab, and enable GNSS configuration. 
{{ :itxpt_gnss.png?400 |}}

Almost done, now we nee to discover the services offered by netmodule ITxPT service.
As discovery tool, we use avahi-discover.
Once, started, we can click on a service to get detail information.
{{ :itxpt_discovery.png?400 |}}

Now we have the multicast address for the gnss service discovered, we can join the multicast group and recvice the udp messages. 

Note: If you are connected to other networks too, make sure to add a route for the multicast address. 
In my case, I add the route: 

<konsole>
sudo ip route add 239.0.0.0/8 dev enp5s0
</konsole>


Please clone https://github.com/troglobit/mtools and build the mtools:

<konsole>
klueppel@fang:/tmp$ git clone https://github.com/troglobit/mtools
Cloning into 'mtools'...
remote: Enumerating objects: 103, done.
remote: Total 103 (delta 0), reused 0 (delta 0), pack-reused 103
Receiving objects: 100% (103/103), 48.67 KiB | 2.32 MiB/s, done.
Resolving deltas: 100% (53/53), done.         
klueppel@fang:/tmp$ cd mtools/
klueppel@fang:/tmp/mtools$ make
  CC      msend.o
  LINK    msend
  CC      mreceive.o
  LINK    mreceive
klueppel@fang:/tmp/mtools$ 
</konsole>

Now we can start mrecevie, with multiacast IP and port:
./mreceive -g 239.255.42.21  -p 14005
<code>
./mreceive -g 239.255.42.21  -p 14005
Now receiving from multicast group: 239.255.42.21
Receive msg 1 from 192.168.1.1:59277: <?xml version="1.0"?><GNSSLocationDelivery version="1.1a"><GNSSLocation><Data>$GNRMC,094445.00,A,5005.47450,N,00840.68303,E,0.015,,151121,,,D*60$GNVTG,,T,,M,0.015,N,0.028,K,D*36$GNGGA,094445.00,5005.47450,N,00840.68303,E,2,12,0.78,119.1,M,47.5,M,,0000*4B$GNGSA,A,3,04,06,19,09,07,03,22,02,26,,,,1.21,0.78,0.93*1A$GNGSA,A,3,85,70,69,84,79,68,78,77,,,,,1.21,0.78,0.93*1D$GNGSA,A,3,312,304,321,309,319,311,336,,,,,,1.21,0.78,0.93*28$GPGSV,4,1,15,02,27,313,45,03,31,106,29,04,63,064,27,06,61,267,47*75$GPGSV,4,2,15,07,22,175,26,09,76,235,31,11,32,309,46,16,01,089,*7B$GPGSV,4,3,15,17,01,217,,19,13,235,46,20,06,295,,22,11,113,21*7F$GPGSV,4,4,15,26,09,052,27,36,29,151,,49,33,185,30*4B$GLGSV,3,1,09,68,31,066,25,69,71,355,27,70,25,273,28,77,12,015,21*62$GLGSV,3,2,09,78,33,069,30,79,20,125,25,84,42,224,20,85,40,311,23*64$GLGSV,3,3,09,86,06,345,*56$GAGSV,3,1,10,301,11,105,,304,76,062,26,309,46,250,47,311,47,205,28*6A$GAGSV,3,2,10,312,06,168,22,318,16,274,,319,17,066,28,321,16,058,21*63$GAGSV,3,3,10,327,04,011,29,336,49,290,45
</code>

Done.