Search found 7 matches

by Guglie
Wed Jan 16, 2019 11:24 am
Forum: Loco Positioning System
Topic: EKF variance and CMSIS nan values
Replies: 2
Views: 165

Re: EKF variance and CMSIS nan values

Hi arnaud, thanks for your reply, So the matrix multiplication from CMSIS library is known to have some specific values that do not work? I'm using a custom firmware to understand and maybe test sightly changes of the TDoA2 localization algorithm, can you explain (or point me where to look at) how y...
by Guglie
Tue Jan 15, 2019 11:39 am
Forum: Loco Positioning System
Topic: EKF variance and CMSIS nan values
Replies: 2
Views: 165

EKF variance and CMSIS nan values

Hi, I've noticed that sometimes the EKF reaches high variance in stateEstimatorScalarUpdate() and that leads to a filter reset. This is due to mat_mult() (from CMSIS-DSP library ) returning inf or nan values sometimes. Have you experienced the same thing? How can I reduce this to achieve better posi...
by Guglie
Fri Aug 03, 2018 1:37 pm
Forum: Loco Positioning System
Topic: TDOA filter explanation
Replies: 0
Views: 694

TDOA filter explanation

Can someone explain the kalman filtering applied to TDOA measurements? In particular the function stateEstimatorUpdateWithTDOA() What's the meaning of these lines? h[STATE_X] = ((x - x1) / d1 - (x - x0) / d0); h[STATE_Y] = ((y - y1) / d1 - (y - y0) / d0); h[STATE_Z] = ((z - z1) / d1 - (z - z0) / d0)...
by Guglie
Thu Apr 19, 2018 2:57 pm
Forum: Loco Positioning System
Topic: TDOA measurement debug
Replies: 4
Views: 504

Re: TDOA measurement debug

Are you using the stock firmware in the anchors? Yes, I'm using the last commit, I've only added a serial submenu for power settings (I'll make a pull request soon with that) If so can you tell me the commit/version you are using and the configuration of each anchor so that I can try to reproduce t...
by Guglie
Tue Apr 17, 2018 1:28 pm
Forum: Loco Positioning System
Topic: TDOA measurement debug
Replies: 4
Views: 504

Re: TDOA measurement debug

Hi Arnaud, thank you for your reply! are the anchor close to a very radio-reflective material like metal or concrete and is the line of sight clear of obstacle? The anchors are at 20cm from concrete, the line of sight is clear. it looks like multipath to me I suppose it is not, I swapped anchor 1 (c...
by Guglie
Fri Apr 13, 2018 12:21 pm
Forum: Loco Positioning System
Topic: TDOA measurement debug
Replies: 4
Views: 504

TDOA measurement debug

Hi, first of all thank you for all this amazing work with Loco Positioning! I'm debugging a TDOA setup with 8 nodes, here's the 3 raw TDOA readings using the first 4 nodes: https://preview.ibb.co/mv1Jgn/tdoa_debug.png Here's roughly the 0-3 nodes placement and in green the 5 positions where I moved ...
by Guglie
Mon Mar 26, 2018 5:29 pm
Forum: Loco Positioning System
Topic: tdoa distance diff error
Replies: 6
Views: 868

Re: tdoa distance diff error

Very interesting, I'm also trying to get better results from TDOA, what are the TDMA_SLOT_BITS?