Tags see nearby anchors in network, but range to less than 3 of them. No position calculated

Wireless Connectivity Ultra-Wideband
1

I have a system with (5) Anchors, (4) tags and a Gateway running an MQTT server on a RPi 3B. At times, everything works properly and I get accurate position updates reported by the tags. For long periods of time though (days), the tags will only range to 1 or 2 of the nearby anchors. All devices in this system are DWM1001-DEV boards with PANS 2. All anchors are configured as initiators since only one will actually act as an initiator and I don’t care which one. Anchor location coordinates are configured individually and are certainly accurate. The full size of the ranging area is less than 6m x 7m with the anchors around the periphery. Tags are configured in low power mode with BLE enabled, moving update rate at 100ms and the normal rate at 10s. I am inquiring into the tag activity through MQTT messages not updating a valid location, and UART shell mode with direct USB connection. Shell command “la” correctly lists all anchors without issue. Command “les” displays that the tags are only ranging to 1 or 2 of the anchors at a time, so it’s not calculating a position. I am not local at the site where this is malfunctioning and need to prepare some thoughts for troubleshooting.

  1. Is it okay to have all anchors programmed as initiators (I believe the PANS network assures only one actually “acts” as an initiator)?
  2. Are there any settings on the anchors that might impact this?
  3. Are there settings on the tags that might impact this?
2

Hi Lembezeder,

It shouldn’t be an issue to configure all anchors as initiator, as you said, only one will effectively behave as such.

Do you know if the tags are always in line-of-sight with the anchors ? Is it possible that there is a temporary obstacle that would prevent correct communication between tags and anchors ?

The best way to debug would be to perform LA/LES on the tag when it actually sees only 1 or 2 anchors.

Thank you,
Best regards
Yves

3

Hi Lembezeder,

  1. I would recommend to not have all as Initiators. If you need redundancy then make 2 or 3 of them to be Initiators but make sure they are in range with each others. In case the real Initiator would go off then one of the other Initiators will take control over the network faster since the issue does not need to propagate. Having all Initiators in a spread area can create a situation, when due to changes in range the ‘backup’ Initiators might lost connection with the network and it would initiate a new one. During a longer period the humidity or other environment changes might create a such condition.

  2. and 3. No other than what I have mentioned in point 1.

Cheers,
TDK