The Joint Army Navy NASA Air Force (JANNAF) model SPectral and In-band Radiometric Imaging of Targets and Scenes - AirCraft (SPIRITS-AC) is a Government-owned system of computer codes that predicts the hyperspectral electro-optical (UltraViolet, VISible and InfraRed) signatures of complete hardbody/plume aircraft configurations in the 0.2 to 25 μm spectral region.  It produces spectral and in-band intensities and in-band images both at the source and at the observer.  The model determines the contrast signature with the background, and it identifies signature components by their source, i.e., exhaust plume, thermal emission, reflected sunshine, reflected skyshine, reflected earthshine and secondary reflections.

The development of SPIRITS has been heavily data-driven, especially by the extensive Air Force in-flight measurement program at Hanscom AFB, MA. The selection of phenomena to include in the model largely stems from analyses of such data, and all model upgrades are tested and validated by making quantitative comparisons to data.

SPIRITS runs on Windows, Linux, and Unix systems.  Source code is provided.  It is run from the command line, as there is currently no official GUI.  Contact Aerodyne Research for info on a free Beta-level SPIRITS GUI.

Application Study Areas

  • Susceptibility
  • Camouflage
  • Tactics
  • Coatings
  • Countermeasure effectiveness
  • Sensor effectiveness
  • Data analysis
  • Test planning

Associated Software

Aerodyne Research provides a number of software packages designed to assist SPIRITS users in the preparation of their SPIRITS work.

SWFView is a SPIRITS wireframe viewer, converter and attribute editor.  It allows the users to interactively inspect a 3D geometry model and assign SPIRITS attributes to regions of that model, and to group/ungroup facets from regions.

imTool is an image manipulation tool developed at Aerodyne for working with SPIRITS generated imagery.  It allows to user to obtain useful statistics on an image and prepare SPIRITS generated imagery for use in a report.  It can also import and export other image formats.

Obtaining SPIRITS

SPIRITS was developed by Aerodyne Research, Inc, and is owned by the U.S. Government and controlled by the JANNAF Signatures Panel under the Exhaust Plume and Signatures Subcommittee.  The model is distributed by the Chemical Propulsion Information Analysis Center (CPIAC). Aerodyne Research is the Industry Coordinator, with responsibility for maintaining the model, correcting errors, and integrating upgrades.

Process to obtain SPIRITS:

  • Contact CPIAC to obtain the necessary forms and instructions (see contact info at top-left of this page)
    • Return signed form with registration/maintenance fee
    • CPIAC will verify your registration
  • CPIAC delivers the model, documentation, and sample runs on DVD
  • CPIAC also sells validated and documented SPIRITS aircraft input sets
  • Call Aerodyne Research for installation support, if needed
Note that the maintenance fee covers support of initial installation only.  Aerodyne is authorized to offer optional training and/or additional support.


  • The SPIRITS Training Course provides a complete intensive introduction to SPIRITS-AC for new users or for users of previous versions. The course lasts for four days, with a 50/50 mix of lectures and hands-on practice sessions. The course is led by Mr. John Conant, who has been Project Manager and lead designer for SPIRITS throughout its development.
  • Each participant is provided with a notebook containing a complete set of the training viewgraphs, plus a PDF copy on CD. Hands-on Sessions are held using supplied laptops, running either Linux or Windows. Snacks and lunches are provided.
  • The cost for each attendee is $2,500.00. Courses are held at the Aerodyne Research facility in Billerica, MA as needed, with a minimum of 5 attendees (not necessarily from the same organization).


 Nightime visible-band computations with SPIRITS, J. A. Conant, F. J. Iannarilli, F. W. Bacon, T. Deas, Presented at the 32nd JANNAF Exhaust Plume and Signatures Subcommittee Meeting, Arlington, VA, April 2011.

Quantitative camouflage paint selection for the CH-47F helicopter, F. W. Bacon, F. J. Iannarilli, Jr., J. A. Conant, T. Deas, M. Dinning, Color Res. Appl., 34, 406-416, 2009.

Updates to the Polarization Version of SPIRITS, J. A. Conant, F. J. Iannarilli, D. C. Robertson, 12th SPIRITS User Group Meeting, Hanscom AFB, MA, 12-16 May, 2008. {abstract}

Improved Computation of Finite-Width Glint Lobes in SPIRITS, J. A. Conant, 12th SPIRITS User Group Meeting, Hanscom AFB, MA, 12-16 May, 2008. {abstract}

Visible band camouflage paint study for the CH-47F using SPIRITS, F.W. Bacon, F.J. Iannarilli, J.A. Conant, T. Deas, M. Dinning, JANNAF 29th Exhaust Plume Technology Subcommittee 11th SPIRITS User Group Meeting, 14-23 June, 2006 Littleton CO.

Development of a combined bidirectional reflectance and directional emittance model for polarization modeling, J.A. Conant, and F.J Iannarilli, Jr., Proc. SPIE, 4481, 2002. {abstract}

Signature Prediction and Modeling, J.A. Conant and M.A. LeCompte in The Infrared & Electro-Optical Systems Handbook, Vol. 4 - Electro-Optical Systems Design, Analysis, and Testing, ed. by Michael C. Dudzik, Environmental Research Institute of Michigan, SPIE Optical Engineering Press, Bellingham WA, 1993.

Spectral Infrared Imaging of Targets and Scenes (SPIRITS), J.A. Conant, Chapter 5 of Volume X of the DARPA Air Vehicle Detection Handbook, ed. by Hans Wolfhard, Institute for Defense Analysis, Arlington VA .

SPIRITS - A Model for Spectral Infrared Imaging of Targets and Scenes, J. A. Conant, J. H. Gruninger, T. Spaulding, T. Thompkins, G. Voltin, and B. P. Sandford, Proceedings of the 1985 IRIS Specialty Group Meeting on Targets, Backgrounds, and Discrimination, ERIM IRIA Center, Ann Arbor, MI,  1985.


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