SBIR-STTR Award

RDRTec proposes to design, develop, and demonstrate feasibility and benefit of adding automatic threat and friendly radar waveform detection techniques to the Common RAdar Collision Avoidance System (C-RACAS). C-RACAS is designated the AN/ZPY-9 and is a part of the future Triton Integrated Functional Capability (IFC) 5 configuration. The C-RACAS has three C-Band Active Element Scanned Array (AESA) antenna systems that provide coverage over the forward regions of Triton (Figure 1). RDRTec is working with Azure Summit who is building both the C-RACAS radar receivers and Tritons Multi-Int Receivers. The tight coupling of the C-RACAS radar controller with ESM processing provides a new opportunity to add spectrum compatibility between C-RACAS and friendly ground radars. Real-time sensed friendly radar parameters are used to adaptively modify C-RACAS beamsteering and waveforms so as not to interfere with vulnerable waveforms of friendly radars.

Benefit:
A successful Phase 1 effort will establish the basis to support maturing these technologies for future transition to the AN/ZPY-9 that is a part of the future Triton Integrated Functional Capability (IFC) 5 configuration. The anticipated results include definition of and supporting analysis for several candidate cost -effective architectures that provide increased performance in ESM and Friendly radar compatibility. This will provide the support for and emphasis of Phase 2 efforts. The timing of this effort and the teaming of RDRTec with the AN/ZPY-9 prime (Raytheon) allow a transition pathway via inputs in SDD program PDR and CDR SETR events.

Keywords:
AESA, AESA, C-RACAS, Triton, ESM

C-RACAS (AN/ZPY-9) integrated onto MQ-4C Triton, satisfies FAA requirements to Detect and Avoid non-cooperative traffic using an Air-To-Air Radar in the National Air Space as well as provide safety for Due Regard operation. It must coexist with other friendly radar systems operating in the same frequency band. While AN/ZPY-9 has robust signal processing protection from received interfering pulses, this study addresses transmit spectrum sharing techniques that provide deconfliction of interference for coexistence with friendly radars. AN/ZPY-9s operates between 5.35 and 5.46 GHz which is protected against other radars and Unlicensed National Information Infrastructure devices. In this frequency band stations in the radiolocation service shall not cause harmful interference to, nor claim protection from, radar systems. Practically, there are numerous legacy radars in this band that cannot be changed to adhere to this note when the AN/ZPY-9 is deployed. Consequently, DO-366 Phase 1 MOPS Para 2.2.4 and RTCA recommendation to ICAO require DAA radars, such as AN/ZPY-9, to have Dynamic Frequency Selection (DFS) which provides for DAA radar switching automatically between frequency channels, within the band, in the presence of interference from another radar. The 5.35 to 5.46 GHz band is currently utilized by many different types of radars. The DoD specifically uses this band for a wide variety of ground based, shipborne, and airborne radars. By far, the most prevalent of these are surface based radars. Some military radars have both narrow-band and wide-band waveforms which sometimes fall within the AN/ZPY-9 operating band. DFS techniques are appropriate to address the narrowband friendly radar emissions per DO-366. Dynamic Frequency Vacate (DFV) was introduced in Phase 1 to address the deconfliction of broadband waveforms, from the military radars, with the waveforms of the AN/ZPY-9. DFV monitors the spectrum for short duration broad-band emissions, within the AN/ZPY-9 operating frequency range, and provides a quick response to suspend radar transmission until the conflict ceases. These suspensions of transmission events will usually only last a few hundred milliseconds. The research focus of the proposed Phase II effort is to further develop and mature, as well as demonstrate, Dynamic Frequency Selection (DFS) and Dynamic Frequency Vacate (DFV) transmit spectrum sharing techniques to support transition of the AN/ZPY-9 to SDD. These spectrum sharing capabilities are critical for the increased operating air space volume of the AN/ZPY-9, while Triton is operating in the proximity of Friendly Ground Radars (FRG) and to directly mitigate potential program-level risks. The secondary research focus is to support the development of High Gain ESM (HGESM) for future addition of upgraded capabilities to the same AN/ZPY-9 system. The HGESM effort is being led by Azure Summit and detailed in their Phase 2 proposal submittal under the same topic.

Benefit:
Transmit spectrum sharing is critical to the AN/ZPY-9 as it enables Triton to operate significantly closer to FGRs to provide collision avoidance than if simple standoff ranges are used. This technology directly addresses a program level risk. The Triton platform will be the initial transition of this technology as the AN/ZPY-9 SDD is expect next year which is a part of the future Triton Integrated Functional Capability (IFC) 5 configuration. RDRTec is teamed with Raytheon on a sole source award for SDD.

Keywords:
C-RACAS, Dynamic Frequency Vacate, AN/ZPY-9, High Gain ESM, dynamic frequency selection, Transmit Spectrum Sharing