Key considerations in infrared simulations of the missile-aircraft engagement

The development of modern imaging and non-imaging infrared missile signal processing and countermeasure techniques strongly relies on high quality simulated imagery of target and countermeasure signatures. Likewise, the development of an effective countermeasure technique or system for aircraft self-protection requires accurate missile behaviour modelling. The development of these algorithms and protocols can be done most effectively in an accurate infrared imaging simulation. This paper investigates the requirements for such a simulation system, supporting the evaluation of the missile behaviour in the missile-aircraft engagement scenario. The development and evaluation of target detection and tracking algorithms, or countermeasure systems, requires a comprehensive simulation environment where thousands of missile flights can be simulated, covering a wide variety of scenarios and signature conditions. The missile seeker algorithms generally detect and classify targets based on intensity, spatial and dynamic characteristics. The key considerations identified for such an imaging infrared simulation system are: 1) radiometric accuracy in all spectral bands, i.e. sunlight and thermal radiance to provide correct colour ratios; 2) accurate emitting source surface temperature behaviour, be it by aerodynamic or thermodynamic heating; 3) high fidelity geo-metrical and spatial texture modelling to provide shape of targets and countermeasures; 4) true dynamics and kinematic behaviour in six degrees of freedom; 5) detailed modelling of signatures and backgrounds; 6) accurate atmospheric transmittance and path radiance models; 7) realistic rendering of the scene image in radiometric, spatial and temporal terms; and 8) comprehensive sensor modelling to account for primary and second order imaging effects. This paper briefly analyses the broader framework of requirements for an imaging simulation system, in the 0.4 to 14 mu m spectral bands. An existing imaging simulation system, OSSIM, is used to evaluate the identified key requirements for accurately simulating the missile-aircraft engagement scenario. Parameters considered include signature spectral colour ratio, spatial shape, kinematics, temporal behaviour, as well as the effect of the atmosphere and background. From this analysis the significance and relevance of the modelled signature elements are reviewed, thereby confirming the key requirements for simulating the missile-aircraft engagement.