Archive for September, 2016

Gait analysis

Tuesday, September 27th, 2016

Finally a video of some of our ongo­ing research …

Progress in MIMU research

Tuesday, September 27th, 2016

Over the last years we have spent a sig­nif­i­cant research effort on analy­sis of the multiple-IMU (MIMU) sys­tems and plat­forms we have built. Recently we have had result of two major efforts published:


I. Skog, J.-O. Nils­son, P. Hän­del, A. Neho­rai, “Iner­tial Sen­sor Arrays, Max­i­mum Like­li­hood, and Cramér–Rao Bound”, IEEE Trans­ac­tions on Sig­nal Pro­cess­ing, vol. 64, no. 16, pp. 4218 — 4227, 2016.

The arti­cle con­tains the first esti­ma­tion the­o­ret­i­cal for­mu­la­tion and analy­sis of MIMU sys­tems. The for­mu­la­tion makes it pos­si­ble to analys fun­da­men­tal prop­er­ties of such sys­tems and to derive effi­cient esti­ma­tors. In the article,we:

  • Derive bound on the achiev­able per­for­mance of MIMU-systems
  • Sug­gest an effi­cient (achiev­ing the bounds) maximum-likelihood esti­ma­tors for such systems
  • Ana­lyze the prop­er­ties and per­for­mance of MIMU-systems by sim­u­la­tions an exper­i­men­tal data


J.-O. Nils­son and I. Skog, “Iner­tial sen­sor arrays — a lit­er­a­ture sur­vey”, Proc. of 2016 Euro­pean Nav­i­ga­tion Con­fer­ence (ENC), 30 May — 2 June, Helsinki, Fin­land, 2016.

Work­ing with MIMU sys­tems, we have come to real­ize that the related results are very much spread out and poorly cross­cited. There­fore, we com­piled a lit­er­a­ture sur­vey con­sist­ing of some +300 pub­li­ca­tions, cat­e­go­rized accord­ing to array setup, study area and appli­ca­tion. The sur­vey also con­tains a descrip­tion of fun­da­men­tal sys­tem prop­er­ties of iner­tial arrays. Our hope is that the sur­vey will pro­vide the inter­ested reader with an overview of the topic and inspire fur­ther research in an area where the rapid devel­op­ment of sen­sor and com­pu­ta­tional tech­nolo­gies pro­vides many new opportunities.

Software updates

Tuesday, September 27th, 2016

I see there has been almost a year since last update. In other words, time for some updates! I will start with some mod­ules soft­ware updates. I’ve recently pushed some soft­ware updates for the embed­ded code. The main updates are:

  • Sup­port for read­ing out mag­ne­tome­ter data from the IMUs
  • Bug­fix for the loss­less com­mu­ni­ca­tion mode. A bug pre­vented pack­ages from being resent.

In addi­tion, numer­ous small improve­ment and mod­i­fi­ca­tions have been made.

The embed­ded soft­ware can be found at: