Militarized Airborne Very Low Frequency (VLF) Receive Antenna

ABSTRACT: For decades, very low frequency (VLF) links have been an important part of Air Forces worldwide logistics infrastructure and response-coordination capability. With an increasingly-global proliferation of nuclear capability, Air Force faces an urgent need to update legacy VLF equipment to reliably support scenarios where its applicability is vital, including the nuclear command control and communications (NC3) environment using the Emergency Action Message (EAM) network. Simultaneously, the proliferation of modern technologies with both intentional and unintentional VLF radiation (including switching power electronics and their VLF-radiating magnetic cores) has created an electromagnetic interference (EMI) environment for VLF reception that has never been worse especially in modern airborne environments. In response to these demands, there is an urgent need to update legacy VLF systems to support a more comprehensive set of foreseeable battlefield scenarios, like those set forth in the Common VLF Receiver vision. During Phase I, FIRST RF built and tested prototypes of each of the key components of our proposed interference-mitigation antenna system. Through this hardware-based approach, we have proven the feasibility of our concept, and have established a low-risk path for the proposed Phase II effort that will culminate in a hardware demonstration and delivery of a prototype antenna system. BENEFIT: As a result of this SBIR, FIRST RFs technology will enable robust EMI mitigation in a highly-sensitive VLF receive antenna. The beamforming technology will have applicability to a variety of military and civilian applications, including improved emergency-beacon tracking/geolocation (especially in high-EMI environments), emergency low-data-rate/local communications. The antenna miniaturization techniques will afford applicability of this VLF antenna system to smaller payloads, including Class 1 UAVs, opening a whole new realm of applications, especially for emergency-beacon geolocation. Finally, demonstration of our novel noise-detection device will not only augment the capability of this interference-mitigation system, but also have relevance and commercial potential in other testing and RF compatibility applications.