To perform multi-sensors simulations, the French DGA/DET (Directorate for Technical Evaluation of the French
Ministry of Defense) uses CHORALE (simulated Optronic Acoustic Radar battlefield). CHORALE enables the user to
create virtual and realistic multi spectral 3D scenes, and generates the physical signal received by one or several sensors,
typically an IR sensor or an acoustic sensor. This article presents different kinds of scenario such as desert, urban, campaign place to evaluate intelligent artillery ammunition. The ammunition described has to detect thermal contrast above a target area for the detection capability and firing decision. The scene is as realistic as possible to give to french army good parameters according to their request in a
typical operational scenario. That includes background with trees, houses, roads, fields, targets, dunes, with different
materials such as grass, sand, rock, wood, concrete... All object in the 3D scene is characterized by optronic parameters
used by CHORALE Workbench. The signal provided by this workbench is adapted by AMOCO workbench which allows defining sensor technology. Then a process unit provides the firing decision and the lethality data from the target which has been reached. Each tool is explained to understand the physics phenomena in the scene to take into account atmospheric transmission, radiative parameters of objects and counter-measure devices. Finally, this paper shows results by coupling the operational scenario with sensor model to do a global simulation in
order to determine global performances of artillery ammunition.
To perform multi-sensors simulations, the French DGA/DET (Directorate for Technical Evaluation of the French Ministry of Defense) uses CHORALE (simulated Optronic Acoustic Radar battlefield). CHORALE enables the user to create virtual and realistic multi spectral 3D scenes, and generates the physical signal received by one or several sensors, typically an IR sensor or an acoustic sensor. This article presents how the expertise is made to evaluate smart ammunition to detect ground target with infrared sensor and shape detector in a virtual battlefield with the environment CHORALE and the workshop AMOCO. The scene includes background with trees, houses, roads, fields, targets, and the ammunition.
Each tool is explained to understand the physics phenomena in the scene to take into account atmospheric transmission, radiative parameters of objects and counter-measure devices.
Then numeric models are described as the 6 DOF ballistics models, sensor model according precise positions inside the ammunition as well as the different steps of calculation between industrial model and technical model to obtain the global simulation.
Finally, this paper explains some results of the evaluation compared with the true behavior after tests on proving ground. Then future evolutions are presented to perform similar evaluation with other kind of intelligent ammunition in a real-time model.
CHORALE (simulated Optronic Acoustic Radar battlefield) is used by the French DGA/DET (Directorate for Evaluation of the French Ministry of Defense) to perform multi-sensors simulations. CHORALE enables the user to create virtual and realistic multi spectral 3D scenes, and generate the physical signal received by a sensor, typically an IR sensor. To evaluate their efficiency in visible and infrared wavelength, simulation tools, that give a good representation of physical phenomena, are used. This article describes the elements used to prepare data (3D database, materials, scenario, ...) for the simulation, and the set of tools (SE-FAST-IR), used in CHORALE for the Real Time simulation in the infrared spectrum. SE-FAST-IR package allows the compilation and visualization of 3D databases for infrared simulations. It enables one to visualize complex and large databases for a wide set of real and pseudo-real time applications. SE-FAST-IR is based on the physical model of the Non Real Time tool of CHORALE workshop. It automatically computes radiance textures, Open GL light source and fog-law parameters for predefined thermal and atmospheric conditions, specified by the user.
To perform multi-sensors simulations, the French DGA/DET (Directorate for Technical Evaluation of the French Ministry of Defense) uses CHORALE (simulated Optronic Acoustic Radar battlefield). CHORALE enables the user to create virtual and realistic multi spectral 3D scenes, and generate the physical signal received by a sensor, typically an IR sensor. This article presents how the expertise is made to evaluate smart ammunition with laser guidance in a virtual battlefield with the environment CHORALE and the workshop AMOCO. The scene includes background, targets, a laser to designate and ammunition. The laser source is reflected by a target in the battlefield and the laser receiver is linked with ballistics model and guidance model via a simulation framework. Each tool is explained to understand the physics phenomena in the scene to take into account atmospheric transmission, radiative parameters of objects and counter-measure devices. Then numeric models are described as the different ballistics models 3 DOF or 6 DOF, sensor model. The step of ballistics calculation gives the cadence of the global simulation through the simulation framework. The 4 quadrants sensor provides gap between the center of optical way and the barycentre of the spot on the sensitive surface computed by a spot weighted method. These data are provided to the guidance and ballistics model to calculate a new position and a new view of the scene with the designated target in the field view. Finally, this paper explains some results of the evaluation compared with the true behavior after tests on proving ground. Then future evolutions are presented to perform similar evaluation with other intelligent ammunition in a real-time model.
CHORALE (simulated Optronic Acoustic Radar battlefield) is used by the French DGA/DET (Directorate for Evaluation of the French Ministry of Defense) to perform multi-sensors simulations. CHORALE enables the user to create virtual and realistic multi spectral 3D scenes, and generate the physical signal received by a sensor, typically an IR sensor. Some assessments concern the study of the duality between a threat (a missile for example) and a target (a battle tank for example) in the battlefield. In these cases, obscurants are special counter measures (clouds), classically used to hide armored vehicles and/or to deceive threatens. To evaluate their efficiency in visible and infrared wavelength, simulations tools, that give a good representation of physical phenomena, are used. The first part of this article describes the elements used to prepare data for the simulation. The second part explains the physical model used in CHORALE for the resolution of the Radiative Transfer Equation when obscurants are set in the scene. Obscurants are modeled by a set of voxels (elementary volume elements). Each voxel contains the spectral absorption and scattering coefficients, phase function coefficient and temperature information. The shape is changing with time to take into account the dynamic evolution of the obscurant. A “photon map” method is used in the ray tracing process to take into account global illumination within the cloud and solve the Radiative Transfer Equation.
To recognize the targets state in a battlefield after shots, it's possible to send a video sensor with the same ballistics than real ammunitions. This article describes the modeling of observation ammunition using simulation workshop CHORALE and AMOCO. Before real trials on a battlefield and to define the final features of an embedded video sensor, it is necessary to modeling each part of the behavior of the ammunition. The goal of this simulation is to know how the ammunition with its movements as the rotation, pitch, yaw can see the proving ground and what values of parameters it is possible to set into the embedded sensor. To perform the simulation, we need of a ballistics model taking into account the geometric form of the projectile. This ammunition flights over a battlefield so we need a realistic 3D scene model taking into account the atmospheric conditions, real target, geometric target and all existing things on a real proving ground as building, forest and so on. The frame seen by the sensor is modified by its transfer function. The video sensor model takes into account lot of functional parameters as Optic, Detector and electronic function. An algorithm takes place at the incoming step in the sensor model and takes into account the rotation during the integration time. Each model calculates independently.
The simulation workshop CHORALE of the French DGA is used by government services and industrial companies for weapon system validation and qualification trials in the infrared domain, and detection of moving vehicles in the acoustic domain.
Recently, acoustic simulation tests were performed on the 3D geometrical database of the DGA/DCE/ETBS proving ground. Results have been compared to the acoustic measurements of the NATO-TG25 trials.
This article describes the trials, the modeling of the 3D geometrical database and the comparison between acoustic simulation results and measurements.
The 3D scene is described by a set of polygons. Each polygon is characterized by its acoustic resistivity or its complex impedance. Sound sources are associated with moving vehicles and are characterized by their spectra and directivities. A microphone sensor is defined by its position, its frequency band and its directivity.
For each trial, atmospheric profiles (air temperature, pressure and humidity according to altitude), trajectories and sound spectrum of moving objects were measured. These data were used to prepare the scenario for the acoustic simulation.
The simulation workshop CHORALE developed in collaboration with OKTAL SE company for the French MoD is used by government services and industrial companies for weapon system validation and qualification trials in the infrared domain. The main operational reference for CHORALE is the assessment of the infrared guidance system of the Storm Shadow missile French version, called Scalp. The use of CHORALE workshop is now extended to the acoustic domain. The main objective is the simulation of the detection of moving vehicles in realistic 3D virtual scenes. This article briefly describes the acoustic model in CHORALE. The 3D scene is described by a set of polygons. Each polygon is characterized by its acoustic resistivity or its complex impedance. Sound sources are associated with moving vehicles and are characterized by their spectra and directivities. A microphone sensor is defined by its position, its frequency band and its sensitivity.
The purpose of the acoustic simulation is to calculate the incoming acoustic pressure on microphone sensors. CHORALE is based on a generic ray tracing kernel. This kernel possesses original capabilities: computation time is nearly independent on the scene complexity, especially the number of polygons, databases are enhanced with precise physical data, special mechanisms of antialiasing have been developed that enable to manage very accurate details. The ray tracer takes into account the wave geometrical divergence and the atmospheric transmission. The sound wave refraction is simulated and rays cast in the 3D scene are curved according to air temperature gradient. Finally, sound diffraction by edges (hill, wall,...) is also taken into account.
KEYWORDS: Clouds, Ray tracing, Scattering, Photon transport, Infrared radiation, 3D modeling, Computer simulations, Light sources, Diffusion, Monte Carlo methods
Obscurant representation is a key component of ground battlefield simulation, especially in the infrared domain. Obscurant are special counter measures (clouds) classically used to hide armored vehicles and deceive threatens. Obscurants are very difficult to represent especially because of multi diffusion effects of hot particles and smoke, but this representation is very important to quantify the efficiency of the decoy. This article describes a new model being involved in the simulation workshop CHORALE of the French MoD. The simulation workshop CHORALE developed in collaboration with OKTAL SE company is used by government services and industrial companies for weapon system validation and qualification trials in the infrared domain. The main operational reference for CHORALE is the assessment of the infrared guidance system of the Storm Shadow missile French version, called Scalp. This new model, integrated in CHORALE, enables to simulate the emitted radiance and the transmission of any pre computed obscurant cloud in the virtual battlefield. In the modeling step, the cloud is defined by a set of "voxels" (elementary volume elements). Each voxel contains the spectral extinction coefficient and the spectral scattering coefficients. The shape, i.e. the voxels content, is changing with time to convey the dynamic evolution of the obscurant. In the Non Real Time rendering step, primary rays are traced inside the clouds. For each voxel, scattering rays are then traced to their neighboring voxels and the local hot sources. Actually, ray tracing is used to solve the Radiative Transfer Equation. The main advantage is to be able to solve it taking into account the synthetic environment: the local terrain, the target hidden in the cloud, the atmospheric and weather conditions. The main originality is the multithreading ray tracing which enables to tackle huge quantities of rays in complex geometric environment.
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