Enhanced 6D Measurement by Integrating an Inertial Measurement Unit (IMU) with a 6D Sensor Unit of a Laser Tracker

Linghui Yang, Ruiying Liao, Jiarui Lin, Bo Sun, Zheng Wang, Patrick Keogh, Jigui Zhu

Research output: Contribution to journalArticle


Six-degree-of-freedom (6D) sensors enhance the measurement capability of traditional three-degree-of-freedom (3D) laser trackers. However, the classical 6D measurement techniques still have shortcomings in actual use, such as the problem of line of sight and relatively low data acquisition rate. The proposed approach by integrating an Inertial Measurement Unit (IMU) with a 6D sensor unit of a laser tracker is effective to overcome these limitations. The error is corrected by the combination of a Kalman filter and a backward smoothing algorithm. The Kalman filter only works when the 6D sensor's data is being sent through, while the backward smoothing algorithm works during the whole process. The experiments are performed to compare the error in three positions and three rotational orientations between the proposed method and the Kalman filter and evaluate the effects of different rates and IMU frequencies on the algorithm. The simulations are also performed to estimate the maximum outage time. The results verify that the proposed method can solve the problem of line of sight and low data acquisition rate effectively.

Original languageEnglish
Article number105902
Pages (from-to)1-11
Number of pages11
JournalOptics and Lasers in Engineering
Early online date24 Oct 2019
Publication statusPublished - 1 Mar 2020


  • 6D measurement
  • 6D sensor
  • Data fusion
  • IMU
  • Laser tracker
  • Optical dimensional metrology

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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