Space-based RF Emitter Detection and Localization Using Field Programmable Gate Arrays

ABSTRACT:In response to SBIR AF141-124 Phase II request for proposal, Rincon Research Corporation (RRC) proposes to optimize and validate the results of the Phase I study, which determined that a constellation of 5-kg 10x10x30-cm low earth orbiting cubesats can geolocate a terrestrial transmitter that is interfering with the communications of a U.S. Government satellite. We optimize Phase I findings for on-cubesat FPGA processing for interference signal detection and geolocation. Phase I findings are validated by construction of an FPGA processing board based on a current RRC design that meets Phase I recommendations of processing power, size, weight, and power. We construct a cubesat payload engineering model with this board. We construct an engineering model of the cubesat with all necessary control, power, and data handling interfaces to perform in-the-loop testing of the payload. We develop a GMAT orbit planning tool for control of the cubesat formation that maximizes geolocation performance. A demonstration of the GMAT planning tool and the payload test is given at the end of the project.BENEFIT:In this project, we demonstrate economically feasible methods for detecting terrestrial RF transmitters from space by construction and test of an engineering model. There are significant benefits to this concept including: 1) these cubesats are low-cost and easily replaced, so there is minimal concern with failure or loss as with high-value assets; 2) a formation is robust and reconfigurable, since all cubesats are identical and they have thrust capability; 3) replacement costs are low and launches are easy to get, so a backup set can be maintained and quickly launched; 4) a new design can be quickly implemented, launched, and tested; 5) each cubesat has significant processing resources, and a datalink between the satellites allows for shared parallel processing. This concept has application in areas beyond protection of USG communications including: 1) detection by the USG of unlicensed use of its radio spectrum within its borders; 2) assessment by the USG of the level of RF communication congestion in open-use frequency bands; or 3) monitoring by commercial entities of ocean shipping congestion for route planning through radar signatures. Also in this effort, we implement a receiver design for operation in a small form-factor cubesat with low power consumption. For more than ten years, RRC has been manufacturing and designing receivers for a variety of customers in the federal marketplace. A smaller, more efficient design will appeal to these customers as well, because it allows reduced size and power requirements.