Multimode Tracking for Next Generation Over the Horizon Radar Real-Time Ionospheric Correction

Propagation Research Associates, Inc., (PRA) proposes to develop a real-time error correction processor using multimode tracking for over the horizon radar. In particular, PRA will leverage its extensive experience in propagation effects and tracking algorithms coupled with target selectivity algorithms to develop a dynamic real-time mode linking process for over the horizon radar using aircraft beacon data. Ray tracing the radar signals from origin, through reflection in the ionoshpere, to the receiver on the ground, an estimate of the expected modes will be produced. This will be compared with the measured modes to provide a uniform detected track from the multiple propagation modes. The detected tracks will be compared to the true tracks of the cooperative aircraft to form an error surface for minimizing errors on uncooperative targets due to unaccounted propagation phenomena. The error surface will be updated as additional aircraft position measurements become available in order to adapt to changes in the structure of the ionosphere. BENEFIT: The problem of multiple propagation modes is a significant issue for over the horizon radar, particular during active ionospheric periods. Through the use of cooperative aircraft targets providing accurate aircraft state information in real-time, a real-time error surface can be extracted to improve the track performance of over the horizon radars independent of the particular atmospheric and ionospheric phenomena inducing the errors. The successful completion of Phase I will result in an autonomous error correction algorithm using an operations research optimization approach. The optimization approach applied to multimode tracking can be extended and modified for other engagement applications including air-to-air and ground-to-air engagements. PRA has already applied a similar approach to force protection against rockets, artillery, and mortars and to enhanced target selectivity for anti-ship missiles. The general operations research approach can be evolved from the successful completion of Phase I for applications to include radar and communications mode linking, missile engagements, UAV operations, robotics and operational logistics. The algorithm can also be applied to asset defense in a multiple engagement scenario with many incoming threats for optimum assignment and engagement of targets such as a swarm of small boats attacking a ship or a swarm of low cost rockets attacking a high valued asset. Other anticipated benefits and commercial applications are in resource allocation for first responders, disaster planning, police chases, etc. In Phase II, PRA plans to develop a simulation to demonstration the processing and exercise the interfaces in preparation for a Phase III implementation into an OTHR system. The processing algorithms will need to be numerically efficient for real-time operations and PRA will develop near optimal algorithms that are capable of achieving fast computation. In addition, PRA plans assess the algorithms using R-OTHR data from Raytheon. In the longer term PRA will continue to develop and commercialize products based on the exploitation and mitigation refraction of signals through continuous media. Applications include, acoustic signature mitigation for tactical operations that need to remain silent, sonar tracking where multiple reflections of the same track have to be reconciled, and identification and mitigation of marine ducting layers that guide radiation in channels of low density air.