delay and pose sensor setup

[fboris]

hi guys,
When I was using pose_sensor.launch as my launch file, I found I always got these message. I'm using imu(very poor imu MPU9250) at 800hz with svo at 60hz.

[ WARN] [1403628860.088846747]: msf_core: imu message drop curr seq:44574 expected: 44561
[ WARN] [1403628860.089542803]: You tried to give me a measurement which is too far in the past. Are you sure your clocks are synced and delays compensated correctly? [measurement: 8859.94 (s) first state in buffer: 8859.96 (s)]

My question is how to set the delay correctly?

Sometime, the fuzzy tracking had been triggered. Then, the filter went to diverge. I refer the fuzzy tracking that mentioned by @simonlynen (ethz-asl/ethzasl_sensor_fusion#20). I checked my quaternion of camera w.r.t imu. It is my opinion: If I set some rotation wrong, it could triggered the fuzzy tracking to the end. But It did not happen. I'm not sure these two issue are related.

Last question, are these two values for pose sensor translation and rotation noise configuration?
in pose_sensor.launch

pose_sensor/pose_noise_meas_p: 0.02
pose_sensor/pose_noise_meas_q: 0.02

[simonlynen]

What CPU are you running this on? It seems the filter gets starved from the CPU and thus drops IMU messages. You can well reduce the frequency of your imu to 100-200Hz to save some cycles.

In case a message is delayed too much it will get dropped. In your case however it looks like this message is plotted right after you start the estimator. Is this correct? The filter has a buffer for measurements of 30s.

Yes fuzzy tracking is either triggered by your visual frontend giving measurements which are outside of the expected noise characteristics or your camera-imu transformation being too off / wrong.

Yes these are the noise densities for your measurement.

[fboris]

My Lenovo x230 has Intel i5 CPU.
You are correct. I got these warning "after" I initialized estimator.
I will check the CPU usage later. The problem might be the the node parsing serial port.

[simonlynen]

Assuming this is resolved.