"Position" attribute disappears in log file

Wireless Connectivity Ultra-Wideband
1

Dear team,

We see strange behavior in our .log files, similar to described in this topic (unfortunately, there’s to answer there from support team): Tag location data inconsistent

So, the “position” attribute disappears from some entries of the .log file. What could it mean? Why the anchors calculate distances, but do not calculate the position based on them? Here is a short part of our log file:

1421.652: 0x…0519 location data: position: x=-2202 y=6162 z=-1516 q=91; distances: 1029 distance=Distance{length=7837, quality=100}, 8E99 distance=Distance{length=4708, quality=100}, 1C9C distance=Distance{length=9576, quality=100}, CF13 distance=Distance{length=6469, quality=100}
1421.768: 0x…0519 location data: distances: 8E99 distance=Distance{length=4384, quality=100}, 1029 distance=Distance{length=8906, quality=100}, CF13 distance=Distance{length=5705, quality=100}, 1C9C distance=Distance{length=9520, quality=100}
1421.902: 0x…0519 location data: distances: 1029 distance=Distance{length=7729, quality=100}, 8E99 distance=Distance{length=2585, quality=100}, 1C9C distance=Distance{length=9524, quality=100}, CF13 distance=Distance{length=6427, quality=100}
1421.950: 0x…0519 location data: position: x=-1777 y=6247 z=-1680 q=90; distances: 1029 distance=Distance{length=6876, quality=100}, 8E99 distance=Distance{length=3353, quality=100}, 1C9C distance=Distance{length=9543, quality=100}, CF13 distance=Distance{length=5593, quality=100}
1422.066: 0x…0519 location data: distances: 8E99 distance=Distance{length=2885, quality=100}, CF13 distance=Distance{length=5677, quality=100}, 1029 distance=Distance{length=8264, quality=100}, 1C9C distance=Distance{length=9534, quality=100}
1422.166: 0x…0519 location data: distances: 1029 distance=Distance{length=7392, quality=100}, 8E99 distance=Distance{length=2871, quality=100}, 1C9C distance=Distance{length=9604, quality=100}, CF13 distance=Distance{length=6563, quality=100}
1422.249: 0x…0519 location data: distances: 1029 distance=Distance{length=8259, quality=100}, 8E99 distance=Distance{length=2843, quality=100}, CF13 distance=Distance{length=6399, quality=100}
1422.367: 0x…0519 location data: distances: 8E99 distance=Distance{length=2866, quality=100}, 1029 distance=Distance{length=7593, quality=100}, CF13 distance=Distance{length=7640, quality=100}, 1C9C distance=Distance{length=9646, quality=100}
2

Hi Vladimir,

In my opinion the post you were referring to was actually answered correctly by Andy.

It seems the range is the main issue. The log does not provide position because it could not calculate it. There can be multiple reasons why this happens

  1. The amount of distances is less than 3. For trilateration to work the minimum amount of distances is 3.
  2. The Anchor position might contain significant errors, so even with enough measurements, the location engine still cannot resolve the position.
  3. The measurements contain too high errors and the location engine could not deal with it.

re: reason 1) To achieve the best range make sure the Anchors are kept at least 30-50 cm from the obstacles. E.g. having the Anchors attached right on the wall surface would affect greatly the range. Similar rule is valid also for the Tag, but is more difficult to achieve.

Cheers,
TDK

3

Dear TDK,
Thank you for reply! We’ll test the system again, adhering to your recommendations!