Search found 87 matches

by kristoffer
Fri Nov 09, 2018 10:10 am
Forum: Quadcopters
Topic: tdoa data of Crazyflie
Replies: 1
Views: 782

Re: tdoa data of Crazyflie

The TDoA log data is a bit messy, sorry about that. It is unfortunately not possible to get a measurement of the distance from the CF to an anchor in TDoA, what you can get is the difference in distance to two anchors (see https://wiki.bitcraze.io/doc:lps:tdoa:principles). You can calculate the esti...
by kristoffer
Wed Oct 17, 2018 12:28 pm
Forum: Developer Discussions
Topic: Variance of Kalman Filter
Replies: 1
Views: 262

Re: Variance of Kalman Filter

Hi!

I tried it out with the Flow deck and get the same result as you. With the LPS system the variance is changing as expected but not with the Flow deck.

Unfortunately I don't understand why. If you find out, please share!
by kristoffer
Wed Sep 26, 2018 5:26 am
Forum: Loco Positioning System
Topic: LPS System - Altitude Hold (z-position) Problem
Replies: 7
Views: 724

Re: LPS System - Altitude Hold (z-position) Problem

Hi! A shortish answer, we are buzzy preparing for IROS... From your videos it looks like measurements to some anchors becomes noisy when they are "far" away. My guess is that the size of your system is on the edge of the reach of the system (with the current settings). There are two solutions for th...
by kristoffer
Fri Sep 14, 2018 12:45 pm
Forum: Loco Positioning System
Topic: LPS System - Altitude Hold (z-position) Problem
Replies: 7
Views: 724

Re: LPS System - Altitude Hold (z-position) Problem

Thanks for the extensive reply and a lot of useful information! Unfortunately I do not have a quick answer to you problem so I think we will have to do some more testing to try to figure out the root cause. First of all some answers to your questions and random thoughts: aiming to test if there is a...
by kristoffer
Mon Sep 10, 2018 9:17 am
Forum: Loco Positioning System
Topic: LPS System - Altitude Hold (z-position) Problem
Replies: 7
Views: 724

Re: LPS System - Altitude Hold (z-position) Problem

The first step is to make sure the positioning system is working properly, without good positioning information the Crazyflie will not be able to do a good job. You say "nodes 2,5 and 7 (placed exactly like in the tutorial) are turning red" - this is the first thing to address. Even though TWR is fa...
by kristoffer
Thu Aug 23, 2018 6:11 am
Forum: Loco Positioning System
Topic: [Solved] Z-coordinate issues
Replies: 6
Views: 468

Re: Z-coordinate issues

Thanks for the videos! In your second video there is a screen shot of the client and it looks as the Crazyflie does not get packets from all the anchors (three of the small boxes at the top right are red). This is most likely why the kalman filter has a hard time finding the position, it simply does...
by kristoffer
Wed Aug 22, 2018 6:59 am
Forum: Loco Positioning System
Topic: [Solved] Z-coordinate issues
Replies: 6
Views: 468

Re: Z-coordinate issues

What happens if you put the CF at other positions in the space? Is the estimated position wrong in other locations as well?
by kristoffer
Tue Aug 21, 2018 7:19 am
Forum: Loco Positioning System
Topic: [Solved] Z-coordinate issues
Replies: 6
Views: 468

Re: Z-coordinate issues

We have got a few similar reports from other users but have not fully understood what the cause is, but we think we might have found the problem now. It seems as there has been some code in the kalman filter that limits the state to positive Z only (most likely used during development and never remo...
by kristoffer
Fri May 18, 2018 9:13 am
Forum: Developer Discussions
Topic: How to change height in height mode
Replies: 11
Views: 871

Re: How to change height in height mode

If you are using the python lib you will have to set up a subscription to the log variable you are interested in with a callback and update your graph from the callback. The other option would be to store the altitude data in an array and plot it when you have disconnected. You can find an example o...
by kristoffer
Tue May 15, 2018 7:18 am
Forum: Bitcraze
Topic: Communication errors and abnormal values in multiple drones
Replies: 1
Views: 230

Re: Communication errors and abnormal values in multiple drones

Hi! Sounds like an exciting project! 1. The best setup for the radios is to use one channel per radio and different addresses for each copter. It looks like you are using the same dongle (the first number in the URIs) for all connections. Maybe try to add a second radio and change URI7 - URI13 to 'r...