Anchor selection rule when LE is disabled


I have a question about anchor selection of DWM1001 tag using default firmware PANS 2.0.
As I understand, tag will range to the closest anchors to its last known position, trying to get an anchor in each qudrant around itselt.
I found that the above anchor selection rule is correct when the location engine is enabled.
However, when the LE is disabled, tag doesn’t follow the rule.
In this case, how the tag select ranging anchors?

Seung beom.

Without the LE engine activated, the tag will not perform any location calculation. In this case you must implement your own location logic and selection of anchors

First, hank you for your quick response.
However, I already don’t understand how I implement the selection of anchors.
As I know, When I use PANS 2.0 firmware (MAC is implemented in the firmware), I cannot see the beacon messages from neighbor anchors.
Thus, when the LE is enabled, the firmware selects 4 anchors and provides them for users.

As I found, when the LE is disabled, the firmware still provides 4 anchors but the selected anchors are different according to the LE’s active state.
Again, I want to raise a question for the avoidance of doubt.
How the firmware select ranging anchors when LE is disabled?

Seung beom.

Hi Seung,

the selection algorithm cannot be changed in PANS. When LE is disabled, the Tag will start measuring with the nearest 4 Anchors from it’s initial position, which is [0,0,0]. After that it will put its position to the center of those 4 Anchors and use that to select the next 4 Anchors.

In practice that means it will keep using the 4 selected Anchors until it lost the range.

I would suggest to always have the LE enabled and do post processing of the distances if needed.
The draw back is that the calculation will take somewhere between 0.7 - 3 ms depends on the amount of measurements.