Common UWB anchors as reference for tags in multiple floors

Hello,
Deployment scenario 1:- Multiple floors in a building with enclosed walls on all the four sides and with ceiling and concrete roof. In this case, the tags in floor ‘x’ will only see the anchors in floor ‘x’ and tags in floor ‘y’ will only see the anchors in floor ‘y’. In this case, we can have two networks with different or same PANIDs and should not be a problem in location determination.

Deployment scenario 2:- In warehouses for example, even though there is a metal ceiling and flooring, it might not be covered with four walls. In this case, the anchors in floor ‘x’ can be heard by tags in floor ‘y’. In this case will the trilateration fail? We are understanding that the tags to anchors distance in the same floor will be different than the tags to anchors on different floors and hence the results will be different How is this deployment scenario handled in decawave?

Regards
Sandeep Suresh.

Hi Sandeep,

Scenario 2: when two networks with two different PANIDs overlaps, all nodes (Anchor/Tag/Bridge) in the overlapped are will share the air-time. The system should work in a such scenario, but due to sharing the air-time, you need to ensure the deployment rules should be applied for the combined network. E.g. the maximum amount of Anchors which can be in-range with each other is 30. As well as the limit of 150 Hz total location for the Tags is for the combined networks.

Cheers,
TDK

Hello TDK,
Thanks for your response. The requirement is that the tag should be able to determine its position via trilateration in any of the floors. Are you proposing for anchors in each floor with different PANIDs? If anchors on each floors are different PANIDs what should be the PANID of the tag? How can a tag with different PANID exchange packets in TWR slots if they belong to different networks? As I understand this will not work?
Regards
Sandeep Suresh

Hi Sandeep,

in PANS it is not possible to assign a Tag to multiple networks, so you understood it correctly.

I don’t propose each floor with different PANID. If you want to cover 3 floors then you could do a test first with 3 smaller installations in each of the floor. E.g. 1 Tag, 3 groups of 3-4 Anchors. All nodes to have the same PANID. Place each of the anchor group on each of the floor if possible at similar X/Y location.

These scenario might happen depends on the signal propagation in the building:

  1. Each anchor group is signally separated - you can enable one Initiator on each of the floor so you would have 3 separated networks using the PANID so they can all provide services for the Tag.

  2. Two or three groups are signally overlapped - ensure you have only one Initiator for the overlapped groups. You can have some backup Initiator but make sure it is in-range with the other Initiator.

Please share the results if you test that.

Thanks,
Cheers, TDK

2 Likes

Very interesting discussion

I have few more questions about a scenario with more than one room and floors. For simplicity, let’s imagine the following scenario as depicted in the Figure below:


Each room with same size (7,2 x 4,0 x 3,5)

My questions:

  1. If one tag will move through all 8 rooms, I imagine the PANID must be the same. Correct?
  2. Is it necessary one Initiator per room? Or only if signal is not overlapped?
  3. What do you means with signally overlapped? An anchor of one room (in my scenario) get signal of a Tag that is positioned in other room?
  4. How do I know if it is necessary use an initiator?
  5. About coordinates. Imagine each anchor is positioned on the corners of room (points A to H), 2 meters from floor. How must we consider the coordinates when define anchors positions? Is the configuration above correct?
  • A (0, 4, 2)
  • B (7.2, 4, 2)
  • C (0,0, 2)
  • D (7.2, 0, 2)
  • E (0, 4, 5.5)
  • F (7.2, 4, 5.5)
  • G ( 0, 0, 5.5)
  • H ( 7,2, 0, 5.5)

Thanks


Ricardo Brandão

1 Like

Hi Ricardo,

  1. Yes, the PANID must be the same. Don’t use different PANID unless you want to separate the networks.

  2. You need only one Initiator per network and since your whole installation should be one network then no need to have initiator per room.

  3. With overlapping I mean the signal can reach to a certain area, i.e. they share the same TX air-space.

  4. When there are Anchors which are out of range of the connected Anchors or in other words when the “ signal chaining” is broken.

  5. Yes, that’s correct.

Cheers,
TDK

1 Like