Re: ntrip and sending position

[Gary E. Miller]

Yo Greg!

On Mon, 16 Dec 2019 16:14:08 -0500
Greg Troxel <address@hidden> wrote:

> I recently tried to use the ntrip support, and have a few questions.
> 
> 1) The man page says: to use a form like:
> 
>   ntrip://foo:address@hidden:80/example-stream

Yup.  I have a NTRIP feed to one a NEO-M8T that I run almost all the
time that way.  From Oregon Real-time GNSS Network (ORGN).

> and I wonder what happens if one's username foo is an email address.

That URL is just used verbatim.  So whatever your NTRIP server wants is
what you put there.

> 2) I am using a service provided by the Massachusetts Department of
> Transportation called MaCORS.  It has a "Virtual Reference Station"
> feature where it synthesiszes corrections for your location based on
> multiple reference stations, and it can also pick the closest,
> depending on the ntrip mountpoint.  See
>   https://macors.massdot.state.ma.us/
> if you are interested; it's available to the public, but only covers
> MA.

A bit too far from oregon to be useful to me.  Hopefully others from MA
give it a try.

> The man page doesn't address sending position.  The Emlid Reach RTK
> has options to 1) not send 2) send a static lat/lon and 3) send the
> current position solution.

For ORGN, that just goes in the URL.  So ask MaCORS what to use as your URL.

> 3) I wonder how to monitor the ntrip stream.

gpspipe.  The NTRIP will show up as another "DEVICE".

Here is what mine looks like, note the 2nd device:

# gpspipe -w pi8
{"class":"VERSION","release":"3.19.1~dev","rev":"release-3.19-945-gbf503e48e","proto_major":3,"proto_minor":14}
{"class":"DEVICES","devices":[{"class":"DEVICE","path":"/dev/ttyAMA0","driver":"u-blox","subtype":"SW
 EXT CORE 3.01 (111141),HW 00080000","subtype1":",ROM BASE 2.01 
(75331),FWVER=TIM 1.10,PROTVER=22.00,MOD=NEO-M8T-0,FIS=0xEF4015 
(100111),GPS;GLO;GAL;BDS,SBAS;IMES;QZSS","activated":"2019-12-16T21:24:56.598Z","flags":1,"native":1,"bps":9600,"parity":"N","stopbits":1,"cycle":1.00,"mincycle":0.25},{"class":"DEVICE","path":"ntrip://rellim:rellim","driver":"RTCM104V2","activated":"2019-12-16T21:24:56.447Z","flags":3}]}

> I am sure it has carrier
> phase, as people talk about RTK with it.  I think it also has
> pseudorange corrections.

RTK is like NMEA 0183.  It defines a few standard sentence types, then
vendors (Leica, u-blox, etc.) add their own proprietary sentences.

Here is what mine looks like, note the 2nd device:

# gpspipe -w pi8
[...]
{"class":"RTCM2","device":"ntrip://rellim:rellim","type":1,"station_id":205,"zcount":1515.0,"seqnum":7,"length":14,"station_health":0,"satellites":[{"ident":26,"udre":0,"iod":71,"prc":-4.160,"rrc":0.000},{"ident":3,"udre":0,"iod":16,"prc":-2.000,"rrc":0.000},{"ident":9,"udre":0,"iod":47,"prc":-2.400,"rrc":0.000},{"ident":16,"udre":0,"iod":58,"prc":-4.860,"rrc":0.002},{"ident":23,"udre":0,"iod":75,"prc":-0.900,"rrc":0.000},{"ident":6,"udre":0,"iod":19,"prc":-5.080,"rrc":-0.002},{"ident":22,"udre":0,"iod":4,"prc":-3.620,"rrc":0.002},{"ident":31,"udre":0,"iod":59,"prc":-6.180,"rrc":-0.002}]}
{"class":"RTCM2","device":"ntrip://rellim:rellim","type":18,"station_id":205,"zcount":1515.0,"seqnum":0,"length":17,"station_health":0,"data":["0x40000016","0xa6930c6c","0x0ab7b2a9","0x60d244b2","0xa87b5c8f","0xe25180c3","0xf9335b61","0x64178935","0x5fbb9443","0xe5d119e2","0x8441b94c","0x219240e1","0x790a9b72","0xa5938b5a","0x864e4cee","0xa7d20471","0x633e3236"]}
[...]

The type 1 is the corrections.  The type 18 is not decoded.

> While I realize the primary path should be
> the MaCORS docs, it seems the gpsd way would have some sort of
> monitor.

For now, just gpspipe, which can give you the raw and/or JSON of the data.

Patches welcome!  If you figure it out, a howto would be nice.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        address@hidden  Tel:+1 541 382 8588

            Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin

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