Optronic Measurement, Testing and the Need for Valid Results Example of Infrared Measurements for Defence Countermeasures Azwitamisi E Mudau, C.J. Willers, M.J. Hlakola, F.P.J. le Roux, B. Theron, J.J. Calitz, M.J.U. Du Plooy Defense, Peace, Safety and Security, Council for Scientific and Industrial Research

© CSIR  Peace and Humanitarian Support  Heat Seeking Missiles and Infrared Countermeasures  Infrared Measurements at the Optronic Sensor Systems  Airborne Infrared Countermeasure Characterization  Strategy for Successful Measurement  Details of Experiments  Equipment used and Settings  Experimental layout  Understanding Infrared Temperature Measurements  Results  Reference Measurements  Flare Measurements  Conclusion Overview

South African Air Force transport aircraft are the platforms of choice to deliver humanitarian aid are used in rescue and support missions used to carry soldiers into countries for UN sanctioned peace support and stabilization efforts the core of the SANDF’s transport and lift capabilities acquired by the country at tremendous cost. If they are destroyed or attacked it seriously limits the ability for South Africa to perform the humanitarian role Peace and Humanitarian Support

© CSIR Heat Seeking Missiles

Infrared Countermeasures

Airborne IRCM flares are defensive mechanisms employed from military and civilian aircraft to avoid detection and attack by enemy infrared seeker missiles.

The Infrared Signature of the Aircraft  The engine hot parts  Exhaust plume  The skin of the airframe

Infrared Measurements at the Optronic Sensor Systems

Airborne Infrared Countermeasure Characterization To model airborne IRCM flares effectively and correctly as missile countermeasures - Radiant intensity - Emissivity - Temperature

Strategy for Successful Measurement Strategy is required for measuring the signatures of infrared countermeasure flares

Details of Experiment © CSIR  Measurements were performed using Cedip Jade LWIR thermal imager  Fluke 574 Precision Infrared Thermometer  A high temperature Electro Optics Industries extended-area blackbody

Prior Infrared Measurements  The Jade IR thermal imagers need to be CALIBRATED  The objective of the calibration is to obtain a relationship between the incident flux and the instrument output (digital level).  They are calibrated over a broad range of temperatures. © CSIR

During Infrared measurement trials  Capture quality IR images of the unit under test (UUT) and two reference source (blackbody)  Instrument settings and meteorological data

Atmospheric Transmittance To account for the target radiation losses through the atmosphere MODerate spectral resolution atmospheric TRANsmission (MODTRAN) code Parameter2009/11/112009/11/12 Atmospheric Temperature [  C] Humidity [%RH] Cloud CoverPartially CloudyCloudy Visibility [km]Good Atmospheric conditions during test

 “The same as” measurement technique was used to calculate the Pyrolysis flame temperature (T m ). Understanding Infrared Temperature Measurements © CSIR  T c is determined from the calibration curves by T c = f cal (D), where D is the measured digital level and f cal is the calibration curve   c is the calibration source emissivity  L bb (T) is blackbody radiation of a source with temperature T  S is the instrument spectral response   ac is the atmospheric transmittance during calibration  T a is the ambient environment temperature   ae is the spectral atmospheric transmittance between the measured source and ambient environment (near unity ) and L path is the atmospheric path radiance (near zero).   am is the spectral atmospheric transmittance between the instrument and the object during measurement   m is the measured source emissivity  T m is the unit under test temperature

Reference Measurements © CSIR Test PointMWIR (K) SWIR (K) Fluke (K)Percentage Difference (%) MWIR / SWIR MWIR / Fluke SWIR / Fluke ± ± ± ± ± ±

Test PointMWIR (K) SWIR (K) Fluke (K)Percentage Difference (%) MWIR / SWIR MWIR / Fluke SWIR / Fluke ± ± ± ± ± ±

© CSIR Flare Measurements

 The methodology used was developed over several field trials, spanning several years.  The deep understanding of the instruments is essential in exploiting the instrument and avoiding its weaknesses.  reference measurements are essential, during field trial to ensure confidence in the measured data.  The results show that atmospheric corrections were done accurately Conclusion © CSIR

Thank you