Mode-Selective OTHR: A new cost-effective sensor for maritime domain awareness

This paper presents a new sensor concept designed to provide maritime domain awareness over large ocean areas. The Mode-Selective OTHR introduced herein achieves significant detection and tracking capability against maritime vessels relative to traditional OTHR designs because it is designed specifically to reject disturbed ionospheric propagation modes and operate only using low distortion propagation modes. The architecture of the radar is such that this rejection occurs for both the transmitter-to-surveillance-footprint and the footprint return-to-receiver propagation paths. This is achieved using recently discovered techniques for non-causal adaptive and range dependent transmit beamforming and two-dimensional apertures for both transmission and reception. It also includes new methods for using planar transmit arrays operating with extreme steer angle.