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-nan, nan, nan in output of NAVSAT TRANSFORM

asked 2018-07-29 19:47:17 -0500

billy gravatar image

I am having an issue with the NAVSAT TRANSFORM node. The output odometry/gps has nan for position and covariance as shown below.

header: 
  seq: 181
  stamp: 
    secs: 1532908689
    nsecs: 471820116
  frame_id: odom
child_frame_id: ''
pose: 
  pose: 
    position: 
      x: nan
      y: nan
      z: nan
    orientation: 
      x: 0.0
      y: 0.0
      z: 0.0
      w: 1.0
  covariance: [nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan, nan]
twist: 
  twist: 
    linear: 
      x: 0.0
      y: 0.0
      z: 0.0
    angular: 
      x: 0.0
      y: 0.0
      z: 0.0
  covariance: [0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0]

If I look at the nodes initializing, as soon as the first GPS message comes in the NAVSAT transform sets the transform heading factor to -nan, and I suspect that is where my problem starts. But I am not sure. I have checked the ODOM, IMU, and GPSFIX messages and none of them have nan in them.

[ INFO] [1532908652.683481047]: Datum (latitude, longitude, altitude) is (37.272746, -121.818616, 46.585000)
[ INFO] [1532908652.683769224]: Datum UTM coordinate is (604740.259728, 4125783.673495)
[ INFO] [1532908652.783517516]: Initial odometry pose is Origin: (0 0 0)
Rotation (RPY): (0, -0, 0)

[ INFO] [1532908652.783951393]: Corrected for magnetic declination of 0.244346 and user-specified offset of 0.010000. Transform heading factor is now -nan
[ INFO] [1532908652.784093424]: Transform world frame pose is: Origin: (0 0 0)
Rotation (RPY): (0, -0, 0)

[ INFO] [1532908652.784163532]: World frame->utm transform is Origin: (nan nan nan)
Rotation (RPY): (-nan, nan, -nan)

Any thoughts on what is causing this?

Here is additional back ground as well as the config information as well as samples of the messages in ODOM, GPS, and IMU..

This is on ROS Kinetic with Ubuntu 16.04

The ODOM message comes directly from the initial publisher. I have not yet passed it through the localization node. I building step by step and currently using simulated (fake IMU data) so no need for localization node yet.

Here is the NAVSAT TRANSFORM launch.

  <node pkg="robot_localization" type="navsat_transform_node" name="navsat_transform_node" respawn="true" output="screen">

    <param name="magnetic_declination_radians" value="0.244346"/>

    <param name="yaw_offset" value="0.01"/>

    <remap from="/imu/data" to="/imu_data" />
    <remap from="/gps/fix" to="/tcpfix" />
    <remap from="/odometry/filtered" to="/odom" />

  </node>

Here is GPS message

header: 
  seq: 3889
  stamp: 
    secs: 1532909977
    nsecs: 461611032
  frame_id: gps
status: 
  status: 2
  service: 1
latitude: 37.2727510883
longitude: -121.81862461
altitude: 47.194
position_covariance: [0.000144, 0.0 ...
(more)
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answered 2018-07-30 04:17:09 -0500

Tom Moore gravatar image

updated 2018-07-30 04:17:35 -0500

NaN values indicate a problem with the sensor data. Offhand, your IMU driver is not filling out the orientation field of your IMU message (you have an invalid, all-zero quaternion). navsat_transform_node needs an earth-referenced heading, so it won't work if your IMU doesn't have a magnetometer.

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Tom, Thanks for quick reply. I will fix the IMU message and report back.

billy gravatar image billy  ( 2018-07-30 13:11:17 -0500 )edit

Tom, I got called away from home for work for a couple weeks so didn't check your solution till now. It works as described. Thanks again for your help.

billy gravatar image billy  ( 2018-08-12 13:32:43 -0500 )edit

That's good to hear. Good luck!

Tom Moore gravatar image Tom Moore  ( 2018-08-13 06:54:10 -0500 )edit

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Asked: 2018-07-29 19:47:17 -0500

Seen: 254 times

Last updated: Jul 30 '18