Check vehicle motion?

I got a new error - Failed to find good IMU rotattion and antenna lever arm - check vehicle motion

any way to fix this? I am out of state in hotel planning to leave tomorrow and don’t want to refly.

We have the same error, any help would be appreciated. Also, my data is processing the reverse IMU but not the forward.

It has been my experience that you will need to re-fly the mission.
Once you have problems with incomplete data, weird data feedback or items “not” working, the output data will suffer massive quality issues.

Unless the Rock Engineers have something new up their sleeve?

@Daniel This issue is typically caused by vehicle motion during the flight not in a forward direction. The two options are re-fly the piece with bad data or send the data files to us for manual work. There is a service cost on that of $250/hour and that usually takes 2 hours of work to trim and delivery, but it may have a 2-3 day turnaround to get through the queue.

Another user had this issue in this post: PCMaster - Failed to find good IMU rotation
In this case our analyst was able to cut out the bad portion of the flight.

Just make sure all motions are forward and while landing you are not making adjustments in any direction as this can cause issues as well.

Once you encounter an issue with data logging, or weird data feedback, be sure to format your drive (after getting all previous flight data transferred to your computer of course). A faulty USB format or read/write session will corrupt all future flights. Our best recommendation is to reformat using the R2A phone interface for every faulty event, prior to each deployment, or unit shutdown.

so to be clear, we talked about any direction over 4m/s being an issue, so it is just backwards motion during any part of the flight? I ran across this on one of my first flights ever and now have had it happen twice in two days just so I didn’t land in some tall grass (but maybe it was something else and I just don’t know) I just maybe need an overly nerded out video explainer on exactly how to not have to go refly stuff again? If I’m bidding on a 5000 acre job I need to know one little nudge to miss a bird / whatever isn’t going to make me redo all that labor, or hope someone else can fix it.


Your final movements are important because you are giving your dataset the final calibration maneuver prior to static collection on the ground.

When returning back to your landing zone be sure to follow these steps:

  1. Fly in the forward flight direction directly (do not turn or change altitude) back to the landing zone at a speed greater than 5 m/s for at least 7 seconds.
  2. Once you are nearing your landing zone reduce your speed to below 3m/s. Once in the 3 m/s portion of the flight you can perform your normal landing procedures (change heading, reduce altitude, etc). NOTE: Once in the 3 m/s portion do not increase your speed to greater than 3 m/s.
  3. Once landed, don’t move the system for 30 seconds. This will capture a final static alignment dataset. Then you can connect via the web interface and stop collecting data and shutdown the LiDAR.

I am coming in for landing, the mission so far has been awesome!
My bird is slowly descending, lower to the ground, lower…
OMG!! The silly bird decides that it wants to not quite line up with the landing pad (last second of course and you just looked over at someone walking by…) and YOUR lidar is going to smash onto a very large, pointy sharp sage bush!!

Option 1: A simple “back” command to the UAV is NOT ADVISED.
Option 2: Would the data be trashed if, in this scenario, we throttled up, flew forward, made a circle and landed?
Option 3: Send the R2A for repairs.

How sensitive is this?

Would also like this clarification. I have done a lot of flights, basically all exactly the same at landing, and now mine are saying I messed up. If anything, I’m being more careful.

@Daniel we believe yours is related to the beta PCMaster you were using.

@FlyingRadioWaves Discussion inline:

Hi Alex,
Yes… assume that we are in landing sequence and the bird is less than 3m/s…

So, I can throttle up and gently fly my bird away from the hazard… and your saying that if I break the 3m/s speed limit (very real chance when you get excited), all I have to do is fly around for a minute and try landing again? SWEET!

In summary:

  1. Fly home, straight line with a good slap of speed.
  2. Fly slow at landing, DON’T GO BACKWARDS
  3. Should your awesome, professionally piloted UAV forget that you need precision landing, we do have options for minor corrections (DON’T GO BACKWARDS)
  4. Unless you do, in which case, go up, fly around a little and try landing again.

Just to clarify a little bit here…

Think of the landing procedure like the start of your flight in reverse (without the figure 8s)…

The high velocity is defined as a fixed direction/altitude exceeding 5m/s for 5-7 seconds.

It is needed at both ends of your capture, obviously at the start it’s not a big deal because it’s all going to be included in your capture and whatever you do is just adding to your point cloud.

The end however needs to be more pedantic simply because YOU are defining the end point! Sooooo after your final high velocity 5m/s for 5-7 seconds in a fixed direction at a fixed altitude. Now DO NOT exceed 3m/s horizontally (in any direction) after that while you are landing or it will use that as your final high velocity and your data won’t process.