Real-time Simulation of Radio Frequency (RF) Signal Returns from Complex Targets and Backgrounds

Navy SBIR 21.1 - Topic N211-091
SSP - Strategic Systems Programs - Mr. Michael Pyryt -
Opens: January 14, 2021 - Closes: February 18, 2021 (12:00pm EDT)

N211-091 TITLE: Real-time Simulation of Radio Frequency (RF) Signal Returns from Complex Targets and Backgrounds

RT&L FOCUS AREA(S): Hypersonics

TECHNOLOGY AREA(S): Information Systems; Weapons

The technology within this topic is restricted under the International Traffic in Arms Regulation (ITAR), 22 CFR Parts 120-130, which controls the export and import of defense-related material and services, including export of sensitive technical data, or the Export Administration Regulation (EAR), 15 CFR Parts 730-774, which controls dual use items. Offerors must disclose any proposed use of foreign nationals (FNs), their country(ies) of origin, the type of visa or work permit possessed, and the statement of work (SOW) tasks intended for accomplishment by the FN(s) in accordance with section 3.5 of the Announcement. Offerors are advised foreign nationals proposed to perform on this topic may be restricted due to the technical data under US Export Control Laws.

OBJECTIVE: Develop a capability for high resolution real-time simulation of targets and cluttered backgrounds for active imaging Radio Frequency (RF) sensors during hardware-in-the-loop testing.

DESCRIPTION: Government hardware-in-the-loop (HWIL) facilities are used to evaluate closed-loop processes associated with weapon guidance and control. To close the guidance loop, the facility must realistically represent the input to sensors used to recognize, track, and guide to the target. In order to develop and test increasingly advanced radar seeker capabilities, there is a need to increase the resolution of the simulated RF scenes. One method of accomplishing this is by increasing the number of RF scatterers used to represent the RF scene. Imaging RF sensors using synthetic aperture radar technology might need on the order of one million scatters to represent the complexity targets and background characteristics.

This SBIR topic focuses on the algorithmic processes and computing architecture required to generate high resolution scenes in a real-time hardware-in-the-loop test environment. The modified return pulses must be calculated and generated based on a dynamic engagement where the engagement parameters and radar state for each update are changing in real time. The scene processing will receive updated state information from the engagement simulation computer at a specified update rate (i.e., 1200Hz). An appropriate computing architecture must be found, possibly graphics processing unit (GPU), field-programmable gate array (FPGA), RFSOC, central processing unit (CPU), digital signal processor (DSP), or combinations of the aforementioned, that provides required increases in processing speed to modify the returned pulse based on target and background interactions. Algorithmic techniques must be defined and implemented to capture the effect of scattered energy in a complex scene (e.g., method of moments, ray tracing) compatible with the real time HWIL test environment. Urban and natural terrains will be bounded pretest, but may extend for considerable distances if used to obtain navigation reference information or if considerable target uncertainty exists.

There are two key steps in creating the return pulse waveform: 1) scene generation that has to occur once per pulse repetition interval (PRI) based on engagement kinematics, and 2) waveform generation that involves convolving the scene with the digitized transmit pulse which has to occur within the time of flight from the radar to the target area and back (t = 2d/c). The goal is the equivalent of 1 million scatterers in the target scene at 10,000 Hz. Note that the use of discrete scatterers to modulate the pulse is used as an example, with understanding that there may be other methods of capturing the effect of complex backgrounds.

The developed technology will be transitioned to Navy and other DoD facilities. For proof of concept and evaluation, the processing architecture must be baselined to communicate/interface with the existing 6DOF engagement systems and the Navy system located in existing facilities. A requirements assessment during Phase I will determine whether any additional interface compatibility is required for other government systems. Designs with modularity that allow for incremental increase in fidelity are possibly of benefit to accommodate budgetary and programmatic constraints. The Phase I effort will not require access to classified information. If needed, data of the same level of complexity as secured data will be provided to support Phase I work. The Phase II effort will likely require secure access, and SSP will process the DD254 to support the contractor for personnel and facility certification for secure access.

Work produced in Phase II may become classified. Note: The prospective contractor(s) must be U.S. owned and operated with no foreign influence as defined by DoD 5220.22-M, National Industrial Security Program Operating Manual, unless acceptable mitigating procedures can and have been implemented and approved by the Defense Counterintelligence Security Agency (DCSA). The selected contractor and/or subcontractor must be able to acquire and maintain a secret level facility and Personnel Security Clearances, in order to perform on advanced phases of this project as set forth by DCSA and SSP in order to gain access to classified information pertaining to the national defense of the United States and its allies; this will be an inherent requirement. The selected company will be required to safeguard classified material IAW DoD 5220.22-M during the advanced phases of this contract.

PHASE I: Bound the problem and develop a processing architecture that can meet the RF scene complexity/resolution goal. Attention will be paid to the best processing architecture or combinations of architectures that best meets the requirements. Document the design and trades made to reach the conclusions. Digital simulations should be executed to demonstrate the capabilities of the design. The software design should use best practices to provide for readability, modification, scalability, reproducibility and support constant evolution into new hardware (H/W) to allow for protection from obsolescence. A facility survey will be performed to determine compatibility requirements with relevant RF target simulators.

The Phase I Option, if exercised, will include the initial design specifications and capabilities description to build a prototype solution in Phase II.

PHASE II: Develop a prototype RF target simulation processing system and deliver for testing and evaluation as a component of the Navy Dynetics system. The prototype shall be based on the results of Phase I and the Phase II Statement of Work (SOW). The prototype shall be software (S/W) that runs on the existing Navy H/W, H/W that interfaces with the existing RF simulator hardware, or shall be some combination of both. Work with Navy subject matter experts, which may include Government personnel and contractors, to develop and demonstrate the prototype with the Navy RF simulator. Fully document the prototype design H/W, S/W and interfaces. The Government will provide the RF sensor and also develop a scenario or group of scenarios to act as test cases to be use to evaluate new scene generation capabilities. Collaborate with the Government to analyze the results of the test cases.

It is probable that the work under this effort will be classified under Phase II (see Description section for details).

PHASE III DUAL USE APPLICATIONS: Support the Navy in transitioning the technology to DoD use. In addition to the Navy system, other DoD and DoD contractor facilities will be identified as potential recipients of this technology. The final product shall be a processing architecture that can generate high resolution RF scenes that are calculated in real-time and interface with DoD facilities. The system needs to be fully supportable and maintainable by the government. The system needs to be adaptable and expandable as technology improves.

This technology can be used to support non-DoD industries such as automotive radar, survey and mapping equipment manufacturing, and simulation for Geographic Information Systems (GIS) satellite radar manufacturers.


  1. Balz, T. "Real-time SAR simulation of complex scenes using programmable graphics processing units." Proceedings of the ISPRS TCVII Mid-term Symposium, July 2006.
  2. Zhang, F.C. "A GPU Based Memory Optimized Parallel Method For FFT Implementation."23 July 2017.

KEYWORDS: Synthetic target scene generation; Real-time RF Target Generation; Synthetic Aperture Radar SAR; Real-time SAR simulation; Radar Scatterers; Simulation of radar returns; Radar background modeling; RF target models


The Navy Topic above is an "unofficial" copy from the overall DoD 21.1 SBIR BAA. Please see the official DoD Topic website at for any updates.

The DoD issued its 21.1 SBIR BAA pre-release on December 8, 2020, which opens to receive proposals on January 14, 2021, and closes February 18, 2021 at 12:00 p.m. ET.

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