MDEK/DWM 1001 Localization

Hey Guys,

I am currently testing the MDEK RTLS kit outdoor. Now according to the data sheet I am supposed to get 65 m of ranging .

My set up involves using 4 anchor points and 4 tags along with a listener device connected to my laptop.

My field size is about 15m X 12m and the anchor points are placed on the corners of the field suspend at 2m height (see the pictures for reference). The anchor positions are highlighted.

The tags were held at about 50 cm above the ground.

I am unable to read any positions of the tag through my listener device. There are a few readings the in certain spots especially along the lines between the anchor points (the sides of the field).

I am using stock firmware in all my devices.

Is there anybody else finding the same problem. Am I doing something wrong? Any suggestions will be valuable.

Regards
V

Hi Vinay,

The listener will report a position only if the location engine finds a solution. It implies that your anchors coordinates are fairly accurate, which is not always easy in a large setup. Have you used auto positioning or measured the anchor coordinates with a laser ruler?

In order to know if the issue comes from the location engine not finding a solution, I would recommend to look at the uart directly out of the tag.

If the tags report at least 3 ranges, then you should get a position estimate. If it is not the case it means there is a high chance your anchor coordinates are not accurate enough.

If you have a position estimate but the listener doesn’t report location, then it may be due to range, but your setup doesn’t sound specifically big (we have already achieved 25*25 outdoor.) When you walk closer to the tag with the listener, do you get more location data ?

If possible, you may want to have the tags a bit higher. Also keep the device vertical if possible in order to get the best antenna gain.

Let me know how it goes,
Thanks
Best regards
Yves

Hi Yves,

Thanks for the reply.

Answering you questions in order.

  1. I took the measurements of the field prior to the experiment and I set the co-ordinates of the anchor points accordingly. To what extent of accuracy must the UWB anchor point positions be set to get accurate localisation of tags?

  2. I have to tried reading the position of the tag via UART yet. I will do so in the next iteration.

  3. Walking closer towards the tag with the listener connected to my laptop made little or no difference to the amount of data collected.

  4. I held the tag higher than 40 cm, the positioning of the tags do not improve.

I now have the following questions.

-> Is there a specific orientation of mounting the anchor points?
-> If you achieved a localisation of tags in a 25m x 25m open space, would you mind sharing the details of that set up. I would like to see if I can replicate the same (this is a university research project).

Kind regards,
V