Comparison of Two (Geometric) Algorithms for Auto OMA

  • Martin JuulEmail author
  • Peter Olsen
  • Ole Balling
  • Sandro Amador
  • Rune Brincker
Conference paper
Part of the Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)


In this paper we compare two geometric algorithms for automatic Operational Modal Analysis(OMA). The compared algorithms are the Shortest Path Algorithm (SPA) that considers shortest paths in the set of poles and the Smallest Sphere Algorithm (SSA) that operates on the set of identified poles to find the set of smallest spheres, containing physical poles. Both algorithm are based on sliding filter stability diagrams recently introduced by Olsen et al. We show how the two algorithms identify system parameters of a simulated system, and illustrate the difference between the identified parameters. The two algorithms are compared and illustrated on simulated data. Different choices of distance measures are discussed and evaluated. It is illustrated how a simple distance measure outperforms traditional distance measures from other Auto OMA algorithms. Traditional measures are unable to discriminate between modes and noise.


System identification Automated operational modal analysis Sliding filter stability Distance measure Smallest sphere algorithm Shortest path algorithm 



This contribution is partly based upon work done in the INNOMILL project supported by the Innovation Fund Denmark, contract number 54-2014-3.


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Copyright information

© The Society for Experimental Mechanics, Inc. 2019

Authors and Affiliations

  • Martin Juul
    • 1
    Email author
  • Peter Olsen
    • 1
  • Ole Balling
    • 1
  • Sandro Amador
    • 2
  • Rune Brincker
    • 2
  1. 1.Department of EngineeringAarhus UniversityAarhusDenmark
  2. 2.Department of Civil EngineeringTechnical University of DenmarkKongens LyngbyDenmark

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