SITIS Archives - Topic Details
Program:  SBIR
Topic Num:  AF071-165 (AirForce)
Title:  High Speed Active RF Synthetic Scene Generation
Research & Technical Areas:  Weapons

 The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), which controls the export and import of defense-related material and services. Offerors must disclose any proposed use of foreign nationals, their country of origin, and what tasks each would accomplish in the statement of work in accordance with section 3.5.b.(7) of the solicitation.
  Objective:  RF Synthetic Scene Generation Optimized for One Transmitter and N number of Simultaneous Coherent Receivers
  Description:  Target detection and classification through the use of active imaging techniques is required for the next generation of short-range, high-resolution, high-speed fuzes. Active systems provide a high probability of detection and excellent countermeasure resistance against advanced surface and air targets. Unlike previous short-range sensors architectures, modern concepts are software driven programmable devices that use sophisticated radar signal processing techniques. The robustness of these new designs now exceeds the capability to thoroughly evaluate their operating envelope using modern PC workstation flyout simulations and RF scene generation tools. Although there are RF scene generation codes available that offer multiple coherent receiver modes, they are extremely slow when compared to the iterative design processing needs of a robust air-to-air and air-to-surface sensor simulation. Operating frequencies of interest for these active imaging sensors are 1-800 GHz. Sources of RF scattering in the synthetic scenes include natural and man-made background objects along with targets of interest. Background objects may consist of the following materials: sand, gravel, asphalt, concrete, brick, short grass, tall grass, and foliage. Targets include every metallic and non-metallic fabricated object that the Air Force could potentially attack. A robust, high-speed, coherent, imaging scene generator that meets the AF’s needs must address the following three areas: 1) a 4-pi steradian representation of each antenna element’s pattern (each element could use the same or a different antenna file). 2) For a defined coherent processing interval (CPI) compute the received energy from each major scatterer in the scene and include the following effects: a) Phase shift due to weapon/scene/target relative motion, b) Proper phase relationship as radar is modulated with step frequency, linear FM, or other technique, and c) Proper phase relationship as multiple modulations sweeps occur during the CPI; 3) Leverage existing target file databases for target definition, and 4) Simulate the last 100 meters of weapon/ target encounter (endgame) fast enough to be useful for the iterative design of the radar, radar signal processing, image processing algorithms, and warhead fire control algorithms. The resultant simulated output file from the radar front end would be the analog In-phase and Quadrature-Phase (I&Q) signal that represents the down-converted received signal from each antenna as if it were produced by a digitizer in a real radar implementation during a coherent processing interval. Radar signal processing techniques could then be applied across all the received elements to emulate Doppler beam sharpening, digital beam forming (DBF), or other advanced radar processing techniques. Implementation is preferred on Windows PC workstations that may be networked for distributed simulation.

  PHASE I: The Phase I effort will be a thorough concept refinement and analysis to show a realistic development path for a scene generator that addresses all of the Air Force’s needs for a robust, high-speed, coherent, imaging scene generator.
  
  PHASE II: The Phase II effort would create the synthetic scene generator, perform validation testing, and perform baseline timing runs.

  DUAL USE COMMERCIALIZATION: Military application: This software capability would enable the iterative design of advanced fuze sensors that use Doppler Beam Sharpening and Digital Beam Forming algorithms Commercial application: As low-cost, high-performance, short-range, software-driven active sensors proliferate, this technology will be poised to provide the only affordable solution for realistic complex RF simulations.

  References:  1. “Radar Reflectivity of Land and Sea”, M. W. Long, Lexington Books, ISBN: 0-669-00050-7. 2. “Common RF Environment Algorithms for Radar Analysis: Joint Bottom Up Development Based on Legacy Models”, J. C. Langenderfer and Robert A Ehret, Proceeding of National Aerospace and Electronics Conference, 1998. 3. “Models of Extended Targets and their Coherent Radar Images”, R. L. Mitchell, Proceedings of the IEEE, Volume 62, Number 6, June 1974.

Keywords:  Active Imaging, Fuzing, Scene Generation, Active Sensors, Distributed computing

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