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ublox package configuration

asked 2018-02-18 16:06:21 -0500

kkrasnosky gravatar image

So-far we have been using the ublox ros package to run our RTK GPS system and we want to send the RTCM3 messages over our own telemetry rather than the built-in radios. We need to: 1. Configure USB port on local (base) M8P to transmit RTCM3 in addition to NMEA and UBX (mode 1+2+32) 2. Configure USB port on remote (rover) M8P to receive RTCM3 in addition to NMEA and UBX (mode 1+2+32) 3. Detect these RTCM3 messages in the driver and publish them 4. Receive these messages in an instance of the driver running on the remote computer 5. Send the RTCM3 messages to the remote (rover) M8P chip

We're using ublox C94-M8P application boards for a base+rover RTK system.

It it possible to configure this package to suit our needs?

I have included what we have so far:

Config File:

debug: 1                    # Range 0-4 (0 means no debug statements will print)

device: /dev/ttyACM0
frame_id: gps
dynamic_model: stationary
fix_mode: 3d                # Switches between 2D/3D automatically
dr_limit: 0                 # Dead reckoning limit
enable_ppp: false           # Advanced setting not supported by all devices
tmode3: 1                   # 1=survey in

rate: 1                     # Measurement rate in Hz
nav_rate: 1                 # in number of measurement cycles

  baudrate: 19200           # baudrate is device specific, check the device manual
  in: 0                     # UBX
  out: 32                   # RTCM

# RTCM out config
  ids: [5, 87, 77, 230]     # RTCM Messages to configure
  rates: [1, 1, 1, 10]      # Rates of RTCM messages above, 
                            # in number of navigation solutions
  set: false                # Do not set the user configured datum

# GNSS Config, verify which GNSS are supported by your device
  gps: true                 # (not required since it defaults to true)
  glonass: true             
  beidou: false             
  qzss: false               
  sbas: false

  all: true                   # Whether to display INF messages

# Message subscriptions
  all: true                 # Subscribe to all messages
    all: false                # ... except AID messages

    min_dur: 300
    acc_lim: 2

    all: true
        all: true

Launch File

<?xml version="1.0" encoding="UTF-8"?>

  <arg name="node_name" value="base"/>
  <arg name="param_file_name" value="ublox"/>
  <arg name="output" default="screen" />
  <arg name="respawn" default="true" />
  <arg name="respawn_delay" default="30" />
  <arg name="clear_params" default="true" />
  <node pkg="ublox_gps" type="ublox_gps" name="$(arg node_name)"
        output="$(arg output)"
        clear_params="$(arg clear_params)"
        respawn="$(arg respawn)"
        respawn_delay="$(arg respawn_delay)">
    <rosparam command="load"
              file="$(find rom_yak)/config/base.yaml" />
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Sorry for being off topic but, any reason in particular to move to your own telemetry over the radios? Currently setting up the same RTK system using the same ublox evaluation kit

TheMilkman gravatar image TheMilkman  ( 2018-02-18 17:18:23 -0500 )edit

@TheMilkman Our main radio system has more range than the radios built into the RTK system. We are also aiming to reduce the complexity of the system by consolidating comms.

kkrasnosky gravatar image kkrasnosky  ( 2018-02-18 17:52:32 -0500 )edit

2 Answers

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answered 2018-02-26 10:59:34 -0500

kkrasnosky gravatar image

I just contacted the package maintainers and According to them this is not currently possible.

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Did you post an issue on the issue tracker of ublox? If so, could you please post a link to the issue so we keep things connected?

gvdhoorn gravatar image gvdhoorn  ( 2018-02-26 11:05:24 -0500 )edit

I would be happy to, however, this is not really a bug/issue, rather, a feature request. Keeping that in mind is it appropriate to post it there?

kkrasnosky gravatar image kkrasnosky  ( 2018-02-26 13:29:37 -0500 )edit

It doesn't matter what it is. If you posted an issue on their tracker, please include a link to it, otherwise it'll be hard to find coming from this ROS Answers Q&A.

gvdhoorn gravatar image gvdhoorn  ( 2018-02-26 13:31:19 -0500 )edit

Coincidentally I've opened a feature request at their github before arriving here:

Timple86 gravatar image Timple86  ( 2018-10-02 07:16:59 -0500 )edit

answered 2018-03-15 02:32:27 -0500

blasalat gravatar image

This won't work with the ublox pkg. But You can set up a ntrip server (either use the built in one in u-center or the BKG ntrip server and caster ) . I found this ros ntrip client usefull. This node will publish the raw RTCM data on a topic. You can easily edit the nmea-navsat-driver to subscribe to the rtcm topic and send it to the ublox device. Make sure you configured both ublox devices to send/recieve rtcm data over usb. I tested this because i needed to transmit the rtcm data via mobile network.

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As far as I undestood is the nmea-navsat-driver for simple outputting data of a gps device. Can you explain how to send the data with it to the ublox with the driver?

tjk gravatar image tjk  ( 2018-05-09 09:09:13 -0500 )edit

@blasalat how was your ntrip server set up? I tried using u-center on Linux with Wine but it seems to freeze every couple of min so it's almost impossible to get a steady FIXED when the server/client connection gets lost every minute.

trixr4kdz gravatar image trixr4kdz  ( 2019-03-06 13:38:58 -0500 )edit

I'd rather not splurge some money over the BKG server/caster if I could (for now anyways), so have you encountered any other way to setup your own simple ntrip server?

trixr4kdz gravatar image trixr4kdz  ( 2019-03-06 13:42:11 -0500 )edit

I've decided to just use a Windows computer to run u-center as my server, but now it seems the messages are encoded somehow. After the first line with "ICY 200 OK" the data just look like gibberish to me. As a result, the /rtcm topic can't even publish any messages. I've tried to use chardet python module to detect the encoding but they're mostly None (though there were a few that are detected as windows-1252). Can someone lend me a hand as to how to decode this messages?

trixr4kdz gravatar image trixr4kdz  ( 2019-03-08 17:40:47 -0500 )edit

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Asked: 2018-02-18 16:06:21 -0500

Seen: 2,219 times

Last updated: Mar 15 '18