On this day I have prepared and tested the RTLS and I have:
1.) 4 Anchors
- with approximately 23 meters distance between:
a. 1st anchor and 4th anchor
b. 2nd anchor and 3rd anchor
- with approximately 7 meters distance between:
a. 1st anchor and 2nd anchor
b. 4th anchor and 3rd anchor
2.) 2 Tags
3.) 1 Listener
4.) Android App
After I’ve setup those, I used the Android application to set the location by using Auto-position. All of the anchors are in line of sight and I’ve mount it on our posts in our office high enough.
Problems Encountered:
The 4th tag has always 0,0 location instead of the 1st anchor after using the auto-position.
The Listener and the tag cannot detect the 3rd and 4th anchor even I’m near the initiator and anchors are line of sight.
Some of anchors have negative location e.g. (-3, 10, 2).
When I’ve tried to setup the 5th and 6th anchors, they are not detected as well.
When I’ve tried to setup manually the locations, all of it is not working.
Questions:
What is the ideal range between anchors?
What is the maximum range of RTLS?
Is it okay to have a 0,0 location on the 4th anchor instead of the 1st (initiator) anchor?
The range between anchors mainly depends on environment and line of sight condition. With line of sight, you should be able to have 25m between and a very reliable RTLS network.
In a 2 device exchange using DWM1001, we have experimented communication up to 60m. This is higlhy depending on the environment. In an RTLS scheme, a tag needs to communicate with at least 3 other device, and it is difficult to have best conditions with 3 devices at the same time. So we would recommend to have 25-30 meters between anchors and the tag in a 30 meters range to each anchors.
The initiator must have the 0,0 coordinates only if you are using auto positioning. Also, note the auto-positioning range is mainly limited by BLE so it is a quick setup functionality but it isn’t really designed for final deployment.
Yes it is ok to have negative coordinates.
The manual setup should work well, what can of issue have you seen so far ?
Thank you for your response! We are continuously testing and it seems that we’ve skipped one important step in auto-positioning which is, Ordering the anchors. With that, we’ve successfully set the initiators location as 0,0. Now, our remaining problem is the range of our listener. Mainly, our target area range is approximately more or less 100 meters. Our question now is, does 1 listener is enough with that vast area range?
I don’t think it is possible to cover 100m with a single listener. The maximum range we have experimented on a DWM1001-DEV to DWM1001-DEV board is 80m, and that is probably in a very favorable environment. The DWM1001-DEV and its software architecture was designed to get the best range/power consumption tradoff and some of the specification are consequently not the best for very long range communication.
To cover 100 meters in a reliable way, I think you will need 3 listeners.
Thanks for your response. Noted with this. We will try our experiments with 3 listeners. On the other hand, can I ask if this 100 meters range are feasible with 3 Listeners within 1 network only?