Wrong distance read with three anchor working together about arduino-dw1000-ng

[Anacron-sec]

I'm glad the ranging is very accurate, having feedback from other sources helps a lot to make sure the changes are working for everyone. We'll start working on the 3 anchor position when we finish to make the ranging messages on the example RTLS ISO standard compliant (almost done). Using the ISO way of doing two way ranging should not give you those errors in the distance as you can check destination and source (just like TCP/IP MAC Layer), that's because i think that thotro's code erroneously makes the 3 ranges of the anchors in parallel so the timestamps are only right on one.
I'm not sure of this because we didn't like how the DW1000Ranging was implemented as a loop so we started to work on our own fork. Hope to publish the new ranging fast so we can all test it out.
Thank you, as always feel free to open issues and help with the project, we'd like to expand our community.

[Anacron-sec]

Oh yeah i forgot about this way of multiple ranging as in the standard you cannot do that as there is no concept of 'anchor' but rather the concept of infrastructure (the anchors are like the communication channel of this system and two way ranging is strictly a flow of messages between tag and the infrastructure)

You can contact me on my email (it's in the github profile) to exchange an other way to communicate faster. Thank you for your support.

[Elon-Wang]

Thank you for your reply!!!
Actually, making 3 ranges of the anchors in parallel is called broadcast in communication, and I don't think this part will go wrong. Although it making 3 ranges of anchors in parallel, it's also have the part of checking destination and source. The frame broadcast to every anchor but the data inside it have the destination check( different anchors with different address and corresponding to different wait time).
And the official datasheet( user manual ) also give a picture to describe the theory of multiple tags & anchors system.(shown as below)

Everything of thoro's code looks non-error from my perspective however, turning out to calculate the wrong distance.😭 It's really confused me. And I think maybe we can have more communicate to help each other to make the targets~ 😃

[Leylan24]

Hi, im planning on using 3 anchors as well have you found a solution?

[Sonic0]

Hi, im planning on using 3 anchors as well have you found a solution?

Hi Leylan24, 3 anchors are supported but not in parallel. The radio protocol does not support this feature in the same frequency channel.

[maeenk]

Hello Again,

I decided to switch from using the NodeMCU to an Arduino Uno. I have been having a hard time with the hardware parts of things. I have finally been able to get the basic sender and receiver examples to run. Finally seeing "Hello" on the receiver side.

I went ahead and started testing for two way ranging. However, these are the outputs I am seeing.

Two Way Responder

Two Way Initiator

I had added a pull up resistor on the IRQ as mentioned from a "closed issue", but the above screenshots are what I see. I see the same result even without the pull up resistor on the IRQ.

Any suggestions?

[Sonic0]

Hi @maeenk , You have set up two different types of configuration for radio communications (last line, Device Mode). In addition, IRQ requires a pull-down resistor to ground. Moreover, pay attention to Arduino and its 5V on SPI instead of the 3,3V required by DW1000.