Loco Positioning System Setup

All discussions related to the Loco Positioning system
arnaud
Bitcraze
Posts: 2028
Joined: Tue Feb 06, 2007 12:36 pm

Re: Loco Positioning System Setup

Post by arnaud » Tue Apr 30, 2019 6:42 am

Hi,
Are all the anchors and Crazyflie updated with the latest firmware? Normally clicking the write button should make all the boxes becomes red and then green when the value is confirmed to be written in the anchors.



Andy
Beginner
Posts: 7
Joined: Wed Jan 16, 2019 5:17 am

Re: Loco Positioning System Setup

Post by Andy » Sat May 04, 2019 11:34 am

Hi,

all parts of the system are updated to the latest firmware version. In the meantime, I found the error and would like to share my solution for others:

I connected each node to the computer via USB. I then used "sudo picocom /dev/ttyACM0" for serial access to the node (picocom can be installed via "sudo apt install picocom"). Note that the device may be different: it could be ttyACM1 or so on. Once connected, I pressed "r" to show the radio settings menu and then selected the first option, corresponding to "normal bandwidth, normal preamble", the default setting, which is required for both TWR and TDoA2 to work. The nodes were previously using "low bandwidth, long preamble" for some strange reason.

After setting all nodes to "normal bandwidth, normal preamble", I could see the green indications in the client. I still get some unexplainable drop-outs from some anchors sometimes, which results in completely random behaviour of the Crazyflies and crashes, but this is not the issue of the current thread anymore.

Regards, Andy

arnaud
Bitcraze
Posts: 2028
Joined: Tue Feb 06, 2007 12:36 pm

Re: Loco Positioning System Setup

Post by arnaud » Mon May 06, 2019 9:25 am

Hi Andy,

Thanks for the update!

Where your not fresh from factory or where they used by someone else before? Tweaking the radio settings can indeed affect the communication between the Crazyflie and the nodes.

Andy
Beginner
Posts: 7
Joined: Wed Jan 16, 2019 5:17 am

Re: Loco Positioning System Setup

Post by Andy » Fri May 10, 2019 2:18 am

Hi Arnaud,

my anchors were freshly purchased and I hadn't done anything but flash the latest firmware on them and configuring their IDs following your tutorial. Anyway, now that their radio settings are configured correctly, I don't encounter many connection problems anymore.

My position estimation is still very off sometimes, which causes a lot of crashes and does not enable me to run the example scripts confidently. I use 6 anchors in TWR mode in an area of approximately 6m x 7.5m x 2m. I notice that someone approaching the drone considerably worsens the positioning up to complete randomness. Do you think that other radio signals around the flying area could cause interference problems or what other reasons could it have?

Best, Andy

envoy
Beginner
Posts: 4
Joined: Wed Jun 19, 2019 3:10 am

Re: Loco Positioning System Setup

Post by envoy » Wed Jun 19, 2019 3:12 am

From where can I download the master version of crazyclient
I am also facing the same issue
No Anchors are coming on my crazy client

arnaud
Bitcraze
Posts: 2028
Joined: Tue Feb 06, 2007 12:36 pm

Re: Loco Positioning System Setup

Post by arnaud » Wed Jun 19, 2019 8:37 am

Hi @andy. With this system size you most likely have problem with the range: with default settings the ancors work very well in a system that is 4x4x3 meters, a bit more is possible but much more requires to change the radio settings.

We have a couple of scripts that can be used to set the anchors radio output power and settings: https://github.com/bitcraze/lps-node-fi ... /tools/lpp. with these script you can set your anchor to max transmit power which should help a lot.

The only problem is that we do not have this kind of settings (yet) available in the Crazyflie, the Crazyflie UWB radio can only transmit at normal power and in TWR mode there is communication in both direction so you need the Crazyflie to increase transmit power as well (in TDoA mode the Crazyflie only receives). Though, this is something that would be quite easy to add to the Crazyflie. If you add the following code around this line https://github.com/bitcraze/crazyflie-f ... eck.c#L439

Code: Select all

dwSetTxPower(dwm, 0x1F1F1F1Ful);
The Crazyflie radio will be set to max power.

@envoy, if you are on windows you can download the client build for master from appveyor: https://ci.appveyor.com/project/bitcraz ... /artifacts. For other OSes follow the readme: https://github.com/bitcraze/crazyflie-c ... c-client--. If you still have problems setting up the LPS please create a new forum thread explaining where you are in the getting started process and how are the LEDs blinking on both the Crazyflie LPS deck and the LPS nodes.

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