<title>High-fidelity simulation capability for virtual testing of seismic and acoustic sensors</title>

Abstract

This paper describes development and application of a high-fidelity, seismic/acoustic simulation capability for battlefield sensors. The purpose is to provide simulated sensor data so realistic that they cannot be distinguished by experts from actual field data. This emerging capability provides rapid, low-cost trade studies of unattended ground sensor network configurations, data processing and fusion strategies, and signatures emitted by prototype vehicles. There are three essential components to the modeling: (1) detailed mechanical signature models for vehicles and walkers, (2) high-resolution characterization of the subsurface and atmospheric environments, and (3) state-of-the-art seismic/acoustic models for propagating moving-vehicle signatures through realistic, complex environments. With regard to the first of these components, dynamic models of wheeled and tracked vehicles have been developed to generate ground force inputs to seismic propagation models. Vehicle models range from simple, 2D representations to highly detailed, 3D representations of entire linked-track suspension systems. Similarly detailed models of acoustic emissions from vehicle engines are under development. The propagation calculations for both the seismics and acoustics are based on finite-difference, time-domain (FDTD) methodologies capable of handling complex environmental features such as heterogeneous geologies, urban structures, surface vegetation, and dynamic atmospheric turbulence. Any number of dynamic sources and virtual sensors may be incorporated into the FDTD model. The computational demands of 3D FDTD simulation over tactical distances require massively parallel computers. Several example calculations of seismic/acoustic wave propagation through complex atmospheric and terrain environments are shown.

Wavelet-based cascade model for intermittent structure in terrestrial environments

“…Random fading and coherence loss in signals results, which degrades the performance of sensor systems used for detecting and localizing emitters, and for communications. The environmental modeling and wave propagation calculations may be done by theoretical (e.g., Tatarskii, 1971;Ostashev, 1997) or numerical (e.g., Anderson et al, 2004;Wilson et al, 2005) methods. In particular, the latter two studies demonstrated how the coupling of synthesized environmental scenes and high-fidelity wave propagation models running on parallel-processing supercomputers enables cost-effective, rapid virtual testing of new sensor systems and employment concepts.…”