Compact Conformal Arrays

Multi-mission systems of the future will require antenna systems with increased aperture size to meet the challenging communications and surveillance requirements. This will include performance in severe interference situations. Planar arrays mounted on either the side, top or bottom of current airframes are impractical, if not aerodynamically unstable. Consequently, the Navy is investing in new RF technologies to support the development of compact conformal apertures and is investigating approaches for mounting/integrating them into a variety of conventional, and future air vehicles including E2C with a circular array, Multi-Mission Maritime Aircraft (MMA), UAV’s and mini-UAV’s. To meet mission objectives, the communication and surveillance systems are expected to rely on space-time adaptive processing (STAP) and super-resolution techniques to achieve the accuracy, resolution and interference suppression performance required. These conformal array systems, however, will face unique signal processing challenges. Many simplifying assumptions made by planar array processing approaches will be violated by conformal aperture designs. As demonstrated by our Phase I results, direction of arrival estimation and point-source interference rejection using compact conformal arrays requires the integration of electromagnetic analysis and adaptive processing (super-resolution, spatial adaptivity). Ongoing work in other programs has shown that a similar integrated approach is required for the rejection of continuous interference (clutter). This other work combines electromagnetic analysis and STAP. In Phase II, we will develop a full capability combined approach to achieve: (1) accurate signal direction-of-arrival (DOA) estimation, (2) parameter estimation for the desired signals, (3)undesired signal rejection, and (4) clutter and multipath rejection. We will focus our effort on specific conformal arrays of greatest interest to the Navy. Specifically we will develop this full capability integrated algorithm for circular conformal arrays that can be employed in Hawkeye-type systems, and non-conventional conformal arrays for future manned and unmanned airborne surveillance and communication systems.