rtk-inconstante

Q&A forumCategory: Questionsrtk-inconstante
topocomputer1 asked 6 days ago

Tengo una placa simpleRTK2B en el cual recibo (o pretendo recibir) correcciones de una base NTRIP. El problema es que a pesar de estar recibiendo paquetes de corrección, solo logro obtener \\ \ “RTK fix \\\” cierto tiempo y luego cae a \\ \ “Single \\\” ni siquiera a \\ \ “float \ \\ “. Tengo configurado UART2 con entrada NMEA + UBX + RTCM y salida NMEA. Comprobó que los mensajes de entrada y salida están habilitados en UART2. Las correciones las obtengo vía bluetooth (modifiqué los baudios a 115200) y los mensajes RTCM que recibo de la base NTRIP son: 1004, 1012, 1033, 1230, 1008, 1005, 1013 Alguna sugerencia para esto superar por favor.

Ardusimple Staff replied 6 days ago

1. What is the distance to the base station?
2. Do you have good GPS+GLONASS reception? Are you next to building or open sky view? Does it still happen in static with good view of the sky?

You are only receiving corrections for these 2 constellations. Also the correction data you are receiving is not fully supported by zed-f9p, 1008 and 1013 are not supported.

topocomputer1 replied 5 days ago

1. La distancia de la estación Base es de 7.8 kilómetros.
2. El equipo rastrea perfectamente GPS, GLONASS, BEIDU y GALILEO, además de SBASS (WASS)
3. Normalmente el equipo está rastreando entre 30-35 satélites, utilizando entre 20-25 según reporta SW MAPS.
Me inclino es por los datos RTCM

topocomputer1 replied 5 days ago

1. La distancia de la estación Base es de 7.8 kilómetros.
2. El equipo rastrea perfectamente GPS, GLONASS, BEIDU y GALILEO, además de SBASS (WASS)
3. Normalmente el equipo está rastreando entre 30-35 satélites, utilizando entre 20-25 según reporta SW MAPS.
Me inclino es por los datos RTCM

topocomputer1 replied 5 days ago

Me inclino es por los datos RTCM que estoy recibiendo, por lo cual en otra pregunta solicité ayuda para ver si era posible, habilitar otros tipos de mensajes RTCM diferentes a los que vienen habilitados por defecto en el dispositivo.

Ardusimple Staff replied 4 days ago

Hi topocomputer1,
You will find in the section RTCM all messages supported by zed-f9p as rover and as base station.
https://www.u-blox.com/sites/default/files/ZED-F9P_DataSheet_%28UBX-17051259%29.pdf

topocomputer1 replied 4 days ago

Se puede concluir entonces, que si la base NTRIP no emite mensajes RTCM 3.3, no habrá posibilidad de obtener correcciones, ni poder tener RTK fijo.

2 Answers
topocomputer1 answered 4 days ago

Se puede concluir entonces, que si la base NTRIP no emite mensajes RTCM 3.3, no habrá posibilidad de obtener correcciones, ni poder tener RTK fijo.

Ardusimple Staff replied 4 days ago

Hi topocomputer, RTCM3.3 is compatible with previous messages also, it just adds new messages. The important are the number of the messages output: 1005, 1074, etc.

topocomputer1 replied 3 days ago

Alguna guía sobre cómo agregar nuevos mensajes?

topocomputer1 replied 3 days ago

Puedo agregar entonces estos mensajes 1004, 1012, 1033, 1230, 1008, 1005, 1013?
Son los mensajes que está emitiendo la base NTRIP. El problema es que no encuentro en ninguna parte, una guía sobre cómo agregar nuevos mensajes RTCM3.3 distintos a los que por defecto U-CENTER deja cargar en el dispositivo.

clive1 answered 3 days ago

It relates to the make/model of receiver the NTRIP provider is using.
Depending on the equipment, and how old it is they may be able to enable additional messages, or update the firmware, or not. This is really a conversation you need to have with them, and if they have plans to upgrade or change in the future.
At the end of the day you might have to set up your own infrastructure, using a ZED-F9P of your own in a base configuration.
If you need to accurately survey the location you might be able to get RINEX data from the current NTRIP provider, you might be able to use RTCM3 to RINEX to generate such files, or there might be a local CORS. Using UBX-RXM-RAWX and RTKLIB you should be able to generate RINEX data for your reference/base antenna, and once you have a post-processed solution you can feed that into your ZED-F9P base station as its static location.

topocomputer1 replied 3 days ago

Hi Clive.
I think the response from the Ardusimple staff was very explicit: “Hi topocomputer, RTCM3.3 is compatible with previous messages also, it just adds new messages”. For anyone reading this, you will believe that old RTCM messages can be added to the board and not that the NTRIP provider is the one who has to add such messages. Anyway I await the official response from the Ardusimple staff.

clive1 replied 3 days ago

I think that may have lost something in interpretation/translation…

What they are saying is that RTCM v3.1 vs v3.2 vs v3.3 there is an incrementation addition in supported messages, mainly related to MSM messages, and likely in support of BEIDOU, GALILEO, QSZZ, or whatever. It’s not particularly material to the discussion, beyond wanting the NTRIP provider to enable more messages, or update to newest firmware, etc.

They aren’t saying that you need to “add” messages.

The uBlox implementation supports a SUBSET of the RTCM3 messages, basically those which are reasonably compatible with their implementation, and supported/provided by some of the large player with whom they want to compete.

The NTRIP provider you’re using would either need to enable messages that they currently don’t, or move to equipment capable of generating a different subset of messages. Or add additional Mount Points with a different mix of messages. They might not want to do any of this, it is their infrastructure, and it might well suffice for their current equipment/clients.