Expected range between anchors not achieved

I’m using four DWM1001-DEV boards outdoors, three as anchors and one as a tag. My anchors are all 2 meters off the ground, in line of sight of one another, and configured as active. When I use auto positioning everything works as expected provided my beacons (shaped in an L pattern) are less than 7 meter apart. Anything farther and auto positioning fails. According to the DWM1001 System Overview document: “For improved performance, it is recommended to space anchors 20 to 25 meters apart when placed in a square grid.” Is there some setting I am missing that allows for this increased range? I upgraded the firmware on all the devices and searched the settings but found nothing relevant. I should also mention there is no metal near the anchors.

Kent

Hi Kent,

Are you running auto-positioning from the android device ?

In this case the range limitation will come from the BLE I believe. Note that the auto-positioning feature is not recommended for large scale setup. In that case we would recommend to calculate anchors coordinates from a floorplan and to configure the anchors manually.

Thanks
Yves

Hi Kent,

please check also that you are using PAND Release 2.

Cheers,
TDK

I verified I’m flashed my dev modules with PANS Release 2. I manually configured the positions of my three anchors but my tag is still not getting it’s location info. I’m using the DRTLS app for my android phone with my tag in one hand and my phone in the other. Standing in clear LOS with nothing between the tag and the three anchors. Does the android app not support a large-scale setup? My anchors are shaped in an ‘L’ pattern with 25 feet and 54 feet between the anchors.

I may be mistaken but I thought that the a tag needs four anchors to calculate location?
In all the examples and documentation I’ve seen there has always been at least four anchors.

Edit: Actually it looks like it is possible with three anchors, but four is recommended. I was able to have my anchors around 25 feet apart but any more and the tag would have trouble being positioned, even with LOS.

Hi Kent,

when you say “it fails” do you mean during auto-positioning? Please keep in mind during auto-positioning the DRTLS Android Manager needs to be in Bluetooth range with the anchors to obtain the measurements. The UWB range should be longer (between 25m-70m depends on antenna orientation between two nodes).

Cheers,
TDK

Perhaps I misconfigured the positions of the anchors (using feet rather than yards). This time everything worked as expected using either three anchors in an “L” shape, or four in a rectangle shape.

When using four anchors in a rectangle shape (25 feet by 54 feet) I was walking diagonally inside of the box from one corner (0,0) to the opposite corner (54, 25). When I got to the opposite corner I kept walking outside of the rectangle. I started experiencing problems connecting with the anchor at (0,0) when I got about 75 feet away from it. I figured the range would be a lot longer than that as the max range of the DWM1001 is up to 60 meters (196 feet) LOS with everything being perfect. Obviously my setup is not perfect conditions but I’m surprised my range is not longer.

Hi Kent,

the antenna orientation can affect significantly the range and I have mentioned before. The range 60m I would expect only in the best scenario when antenna are well oriented to each other and the signal is out of the Fresnel Zones.

Cheers,
TDK