Multiband, Subsurface RF Positioning System

This Navy seeks technology to enhance the performance and survivability of Explosive Ordnance Disposal (EOD) Mine Countermeasure (MCM) equipment in a broad range of contested operational environments, specifically high-risk mine areas, and improve EOD’s ability to enable fleet access and maneuver. Cornerstone Research Group, Inc. (CRG) proposes to develop a Multiband, Subsurface Radio-Frequency Positioning System (MSRPS) which uses a combination of RF bands to detect and calculate the position of various nearby objects. The advantages of an RF-based sensing modality include the elimination of acoustic and DC magnetic field interference which have been shown to negatively impact other mission systems and MCM operations. A property of water is that it attenuates certain RF frequencies, but by choosing the appropriate RF frequency bands a balance can be struck between detection range, accuracy, and signature. In fact, the predictable attenuation of RF signals though water can be turned to an advantage and used to limit the standoff distance at which an adversary is able to detect and monitor the operation. The proposed MSRPS system would consist of an emitter/receiver unit which transmits into the surrounding area and extracts phase and Doppler-shift information from the return signal. This data is then used to calculate relative position information for various objects. A high-frequency carrier wave will be used to pinpoint the position of nearby objects. This high-frequency wave provides good positional resolution but the properties of water prevent it from propagating more than a few meters. A second, low-frequency wave with better propagation through water will be used to achieve good range, with the understanding that the longer wavelength will necessary limit the position resolution at longer distances. Within the Phase I, CRG will use their computational electro-magnetics (CEM) capabilities to conduct trade studies and select a viable architecture. CRG will also use their in-house RF testing equipment which will encompass the necessary sensing modalities/frequency bands in order to empirically assess the feasibility of using different sensors for position detection. The Phase I will culminate in a thorough and fundamental understanding of multi-band position detection through salt and fresh water which will lay the foundation for the Phase II effort in which CRG will develop a working MSRPS prototype.