Unable to Configure Anchor Positions

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Joined: Thu Oct 24, 2019 10:15 pm

Unable to Configure Anchor Positions

Post by wing » Thu Oct 24, 2019 10:23 pm

I am currently using 6 anchors to fly one crazyflie drone. However, I am unable to configure the anchor positions. When I click "Write to anchors" there is no change.

The Anchors are being recognized on the Crazyflie client. I have the latest firmware flashed on both the crazyflie and the anchors. Initially, I was able to configure the position on two of the anchors, but when I tried to configure it again, it would not change.

Any assistance would be greatly appreciated. Thanks!

Kirill Shchukin
Posts: 1
Joined: Tue Nov 19, 2019 12:37 pm

Re: Unable to Configure Anchor Positions

Post by Kirill Shchukin » Tue Nov 19, 2019 12:43 pm

We have the same problem but use 8 points , all sensors are green in CF Client but they dont apears as points at system and we cant "write to anchors" pls help us !

Posts: 256
Joined: Tue Jun 30, 2015 7:47 am

Re: Unable to Configure Anchor Positions

Post by kristoffer » Thu Nov 21, 2019 9:05 am

I'll start with a short explanation of how this mechanism works.
1. When you click the "Write to anchors" button, the client sends a message per anchor to the Crazyflie with the new anchor position information.
2. The message is forwarded to the LPS deck that transmits the same information over the UWB radio to the Anchor/Node. Note: depending on which positioning mode that is used, this message is handled differently to fit into the used scheduling mechanism.
3. The node receives the message and sets the position in its configuration
4. The anchor transmits its (new) position as a part of the normal information flow
5. The CF receives the position information and stores it
6. Every 5 seconds, the Client requests position information from the CF using the mem sub system
7. The (new) position information is used to update the values in the anchor position dialog box as well as graphics.

There are a few properties that are worth pointing out:
a. There is no mechanism in step 2. that ensures that the Node actually received the message. As far as I remember we send the same message a few times to increase the probability, but there is no guarantee. Moving the CF close to each anchor and clicking the "Write to anchors" button to retransmit the messages is probably a good test.
b. The turnaround time from clicking the "Write to anchors" until it is updated in the anchor position dialog is very long (5 seconds)

Suggested tests to solve the problem would be:
* Move the CF close to an anchor and write positions
* Do you get any position data from the anchors at all? Note: if the anchor is new, no position will be transmitted, it will only be transmitted if a position has been set at some point.

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