Active vs. passive tracking: When to illuminate?

Derek Burrell, Joshua Garretson, Jeremy Vorenberg, Ronald Driggers

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations


This paper seeks to address whether active or passive tracking is preferable in terms of centroid-Track error. Active tracking has the advantage of allowing for SWaP-limited source control to scale SNR. With coherent illumination, however, speckle noise gives rise to a fundamental limit in tracking precision. On the other hand, passive tracking relies on incoherent illumination with speckle-free return. The drawback in this case is that SNR itself is inherently limited, thus limiting precision with respect to tracking measurements. In our analysis, we first present the theory that drives limiting factors of both active and passive tracking schemes. From these limitations we then estimate Strehl ratio at various SNRs for direct comparison of active and passive performance. We consider objects of various shapes and sizes, study both well-resolved and unresolved objects, and anchor our findings to first-order simulation results that demonstrate significance in the design of tracking systems.

Original languageEnglish (US)
Title of host publicationInfrared Imaging Systems
Subtitle of host publicationDesign, Analysis, Modeling, and Testing XXXIII
EditorsGerald C. Holst, David P. Haefner
ISBN (Electronic)9781510650886
StatePublished - 2022
EventInfrared Imaging Systems: Design, Analysis, Modeling, and Testing XXXIII 2022 - Virtual, Online
Duration: Jun 6 2022Jun 12 2022

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X


ConferenceInfrared Imaging Systems: Design, Analysis, Modeling, and Testing XXXIII 2022
CityVirtual, Online


  • (in)coherent illumination
  • active/passive imaging
  • extended objects
  • laser speckle
  • modeling and simulation
  • radiometry
  • signal-To-noise ratio
  • target tracking

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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