LPS Anchor Communication Issues

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Joined: Fri Mar 13, 2020 9:07 am

LPS Anchor Communication Issues

Post by hsalman »


We have been experiencing chronic problems using LPS when working with a set-up with the following HW/SW configurations;
  • Crazyflie 2.1
  • Flow deck v2
  • An example beacon set-up (from among many others we changed) can be seen in attached lps1.jpg
  • We are using the autonomousSequence.py script giving different set-points to see some self flying behaviour (later some tracking + path planning will be integrated)
When CFclient is connected with Crazyflie on the ground facing the appropriate x direction; None of the anchors located at ground level is identified as seen in image attached lps2.jpg.
This changes however if we place the Crazyflie at its same starting position but on an elevated level i.e a chair or box. In this case most of the anchors are seen.

Some Approaches we considered
  • We have alternated the positioning in various ways; placing all the beacons on the ground on a higher level (i.e. each on a small box), we placed beacons slightly closer to each other (not closer than 2m as adviced in documentation). But the same issue recurred. Is there anything you may point out on these?
  • The area we are using for the Crazyflie is a robot soccer field of 12m x 9m dimensions which is inside a departmental area. But beacons are placed closer than the field size so connection is stable. Yet could indoor room size we use have an effect on beacon communication?
Despite all of this, the Crazyflie is able to hover / move sufficiently stable when the python script runs. Unfortunately, we are unable to track how well the beacons are connecting during flight because CFclient needs to shut down when the python script runs.

Yet again, we would like to get your suggestions on how to obtain full coverage from our beacons.

Thank you.
Posts: 367
Joined: Tue Jun 30, 2015 7:47 am

Re: LPS Anchor Communication Issues

Post by kristoffer »


There is a known issue of using the LPS and Flow deck at the same time https://github.com/bitcraze/crazyflie-f ... issues/523 It is probably a good idea to start out without the Flow deck to understand what is going on.

I see that it is anchor 0, 2, 5 and 7 that are not visible, they are all at z=0. Are they very close to the floor? If they are, you could maybe try to move them up 10-20 cm?

It looks like your space is around 9x7x2 m, this is maybe a bit too far for the default settings. A good start could be to set up a smaller system (say 3x3 m) to make sure it works.
Next step would be to increase the anchor TX power, see https://www.bitcraze.io/docs/lps-node-f ... el-config/ to see if that makes a difference.
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