Multiple Tag Acquisition

Wireless Connectivity Ultra-Wideband
1

Hi,

I am using two DWM1001 modules for a project, I am acquiring data through a listener onto my PC via the shell and ‘les’ command.

When I acquire data at 10Hz, the tag data comes through in pairs for each time stamp, for example:

les

dwm> [002043.860 INF] loc_data: 2
0) 492B[1.99,1.12,-0.28,100,xD2]

  1. 8321[2.25,1.20,-0.20,100,x68]

[002043.960 INF] loc_data: 2
0) 492B[1.99,1.12,-0.29,50,xD3]

  1. 8321[2.25,1.20,-0.18,100,x69]

[002044.060 INF] loc_data: 2
0) 492B[1.98,1.11,-0.31,100,xD4]

  1. 8321[2.26,1.20,-0.19,100,x6A]

However when I lower the data rate, the tags become out of sync and I receive the tag data at separate times, for example at 5Hz:

les
dwm> [003464.870 INF] loc_data: 1
0) 492B[2.40,1.38,-0.21,93,x21]

[003464.970 INF] loc_data: 1
0) 8321[2.12,1.42,-0.11,100,xDE]

[003465.070 INF] loc_data: 1
0) 492B[2.40,1.36,-0.22,50,x22]

[003465.170 INF] loc_data: 1
0) 8321[2.13,1.42,-0.12,100,xDF]
[003465.270 INF] loc_data: 1

Is there a way that I can synchronise the tags so I can acquire the data from both tags with the same time stamp regardless of the data rate?

Thank you in advance,

Joel

2

Hi Joel,

I don’t think there is an easy to group the data. The quickest way is probably to do it post processing of the result.

I’m not quite sure what the data are not grouped if you are using the same data rates for both tags, I’ll take a look at that.

Thanks
Yves

3

At the base of it all there is a 100 ms repeating superframe (see System Overview doc). There are 15 ranging slots in it. Tags will listen and choose free slots in which to perfrom ranging exchange. If you switch on one tag at a time, then the slots will be taken in sequence. However if you are at a rate of 5 Hz, then if the 1st tag chooses an even superframe slot, then the second tag may choose a slot in either the even or the odd frame. You cannot force a tag to select particular slot.