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2015-08-19 14:15:02 -0600 commented answer robot_localization GPS integration error

I still have the process noise covariance matrix from clearpath's commit. But I have no idea if it's correct. Do you know of some literature on how to tune this. Or should I remove it completely?

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2015-08-19 14:12:54 -0600 commented answer robot_localization GPS integration error

Looks like it works now. The main difference I have to your launch file is that I am using the local odometry as the input to the global odometry with it set as an absolute input. The mag declination I had already but it should be negative I believe.

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2015-08-19 10:15:41 -0600 commented answer robot_localization GPS integration error

This is a surprising result. I didn't think to suspect the transform node because the position seemed stable enough. I guess It changes the frame that the transform node sets in the header. I am going to test this asap and im going to try to use my own launch files.

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2015-08-13 15:20:17 -0600 commented question robot_localization GPS integration error

Ok I updated the bag. I just recorded all this time. I was avoiding this b/c the wiki said rosbag would drop a few of the first messages on a new topic.

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2015-08-11 09:58:58 -0600 commented question robot_localization GPS integration error

I have tried that and I have tried duplicating the inputs from the first with the addition of the GPS.

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2015-08-10 16:00:20 -0600 asked a question robot_localization GPS integration error

###Overview I have been having quite a hard time with setting up my robot to use its GPS. I am attempting to use the navsat_transform_node and two instances of robot_localization. The set up is almost identical to the example in the wiki.

However, the localization node which combines the gps data to the data of the first localization node acts wildly. The transform it produces slowly drifts but then shoots off into one direction and doesnt stop. It sometimes rotates around the initial position while moving outwards. This happens with the robot standing still. The gps data does vary slightly and wanders a bit but within a closed area.

To get some context The robot I am using is a Jackal. It has a laser mounted up front and gps and imu built in. Much of the ros code for the integrated sensors runs on the onboard computer and is installed via debs making it difficult to modify. The GPS integration is running on my laptop which communicates to the jackal through through LAN to a router then through WiFi. I have made sure that the times are synced because this was giving me issues earlier.

###More Detail I have three frames of interest map, odom and base_link. Odom->base_link is generated by a primary localization node which combines an IMU which is earth referenced (the orientation includes the magnetometer) and wheel odometry. The second localization node combines the gps odometry from navsat_transform and the output of the first localization node. (I have also tried to combine the wheel odometry and imu directly in this node) This creates the map->odom transform.

I have used an old commit for the jackal as my starting point. Its intention was to implement this gps integration but then was removed for later development. The commit is found here. I haven't made too many changes to these file other to include a yaw offset (the imu has north pointing to x+) and magnetic declination. I have just tried making small changes to try to see if anything would help.

###Thoughts I'm not sure but I have a feeling that there is trouble transforming the data from a frame on the robot up to the map frame. To me it doesnt make sense to use data in a frame below the transform you are trying to create. You need to use the transform you're creating to transform the data to create the transform. It seems to me like a cyclical problem. But this may work I'm not sure.

The feeling im getting from what I'm seeing is that the gps is drifting a little bit and the transform is drifting as a result. Then a jump occurs in the gps data and through some delay in the tf and the fact that there is some cyclical component to the setup the same value gets added to the system repeatedly. (Data gets transformed using old tf, tf gets updated using previous ... (more)

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2015-05-27 16:01:12 -0600 answered a question Qtcreator with Catkin

I would like to add for anyone looking at this question from now on that now you can compile and add one package from your catkin workspace as a project in Qt. With the new catkin_tools package there is no top level cmake file and therefore no symlink issue.

  • To setup your project you first need the catkin tools package. I installed this with apt-get as follows sudo apt-get install python-catkin-tools There are some differences between the tools package and the catkin_make your used to (now its catkin build) but ill leave it to you to read the docs.

  • You will need to reinitialize your catkin workspace. I found that you can just reuse an existing workspace but I I'm not sure if it will cause me issues down the road. First clean your workspace ie delete build and devel. Then run catkin init and it should inherit the configuration from the original workspace. You should see that it is Extending /opt/ros/indigo or similar. If not you'll have to add it. (See:Workspace Chaining)

That should be it for catkin_tools. Now you can build with catkin build instead of catkin_make or clean with catkin clean -a

The rest of the steps are almost identical to @Jose Luis Blanco except that when adding the project add the CMakeLists.txt of the package its self and set the build folder to ws/build/your_package instead of ws/build as before. (See: ROS IDEs)

Also there is another tutorial out there similar to Jose's but has the build settings as follows ../src -DCMAKE_INSTALL_PREFIX=../install -DCATKIN_DEVEL_PREFIX=../devel if you have that remember to remove the ../src