Communication problem Between Anchors and Tag

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EgeYlcn
Beginner
Posts: 12
Joined: Fri Jan 19, 2018 6:28 am

Communication problem Between Anchors and Tag

Post by EgeYlcn » Tue Mar 27, 2018 8:29 am

Hi everyone,

I have a problem that I hope you will help. I use the TDoA positioning method in the project. When I use the Bitcraze positioning code , I face a problem about communication between devices ( anchor and tag ) .

My Tag that I want to track is not correctly communicate with anchors. I expected that my tag communicate with anchor alternate. For instance, I expected that the "state_packet" I define to hold communication packages is given the following values ; [0.Anchor 1.Anchor TdoaDist_0n1], [0.Anchor 2.Anchor TdoaDist_0n2], [1.Anchor 3.Anchor TdoaDist_1n2] . I use the 4 Anchor and 1 Tag. Anchors name is "0,1,2,3". TdoaDist value is hold the distance difference anchors ( For Example ; TdoaDist_0n2 , distance difference between 0. and 2. anchors ) .

After a while, While I am waiting for such communication packages , I face the wrong packet like [0.Anchor 1.Anchor TdoaDist_0n1],[0.Anchor 1.Anchor TdoaDist_0n1],[0.Anchor 1.Anchor TdoaDist_0n1],[0.Anchor 1.Anchor TdoaDist_0n1],[0.Anchor 1.Anchor TdoaDist_0n1]. In here, 0. and 1. anchor communication with each other. However, I do not want to do this. I expect to have packages with different communications.

How can I solve this problem ? Please help.

Best Regards,

Ege

arnaud
Bitcraze
Posts: 1888
Joined: Tue Feb 06, 2007 12:36 pm

Re: Communication problem Between Anchors and Tag

Post by arnaud » Wed Mar 28, 2018 7:21 am

Hi,

I do not understand your problem, maybe some information about what you are working on and what you are trying to achieve would help:

- What code are you using, are you using the anchor and tag code unmodified of have you done modification to it? Our implementation of TDoA only defines one packet type, rangePacket.
- Are you trying to have the TDoA tag to transmit as well? The way our TDoA implementation is working is by having the anchors communicating and ranging with each-other. The Tag is only listening and is not sending any packet. I assume you already know about it but there is some doc about how TDoA is currently implemented: https://wiki.bitcraze.io/doc:lps:tdoa:protocol

EgeYlcn
Beginner
Posts: 12
Joined: Fri Jan 19, 2018 6:28 am

Re: Communication problem Between Anchors and Tag

Post by EgeYlcn » Wed Mar 28, 2018 8:07 am

Hi Arnaud,
First of all , thanks for your answer.

I know that The Tag is only listening. When I analyze the communication line, I saw that communication is not true for anchors each other.
I expected that every anchor communicate each other respectively based on TDMA method.

However, my system working true first 20 seconds. Afterwards , For example just 0. and 2. anchor communicate each other. ( I have 4 anchors : 0,1,2,3 anchor index respectively) .

arnaud
Bitcraze
Posts: 1888
Joined: Tue Feb 06, 2007 12:36 pm

Re: Communication problem Between Anchors and Tag

Post by arnaud » Wed Mar 28, 2018 9:30 am

Hi thanks for the precision.

- What version of the code are you running?
- How did you observe the packets, are you using one node in sniffer mode?

EgeYlcn
Beginner
Posts: 12
Joined: Fri Jan 19, 2018 6:28 am

Re: Communication problem Between Anchors and Tag

Post by EgeYlcn » Wed Mar 28, 2018 10:26 am

Hi Arnaud,

I'm using Crazyflie 2.0 but I'm not use the Tdoa version 2.

There is not any sniffer node device . I'm use the 1 Tdoa Tag and 4 Tdoa Anchor.

Thank you ,

Ege

arnaud
Bitcraze
Posts: 1888
Joined: Tue Feb 06, 2007 12:36 pm

Re: Communication problem Between Anchors and Tag

Post by arnaud » Thu Mar 29, 2018 8:19 am

Is it possible for you to update the firmware to use the newest TDoA implementation? The newest TDoA should behave much better and I do not remember in details how the previous implementation worked.

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