Virtual SATCOM: Assured Agile Communication in a Satellite Contested Battlefield

摘要

Virtual SATCOM is wireless communication at SATCOM speed on a High Frequency (HF) Skywave channel without a physical satellite. Naval Power's Achilles heel, in the era of networked warfare, is the communication satellite. Adversaries understand this vulnerability, and some are poised to attack this exposed capability. DOD needs a SATCOM alternative to mitigate the space vehicle vulnerability.In the Virtual SATCOM system, we moved the signal repeater (the satellite) to the earth's surface, and the system uses HF signal frequencies that optically bend in the ionosphere to connect a user (ship) to the ground base repeater and then relayed to another user. The Virtual SATCOM repeater increases power and gain, and the narrow beam reduces interference with other users. The Ionosphere bends the signals to enable a ground-based over the horizon communication links. Our design is a new way to use the high-frequency band to obtain high-speed data rates.The ionosphere is an underutilized channel that can mitigate satellite dependent command and control. Our modeling has shown the ionosphere can be harnessed to communicate at a long-range (3000 km) and high speeds (12 Mbps). Compared to SATCOM, current HF protocols are too slow. Virtual SATCOM is a new disruptive technology that increases the data rate by 1000 but also requires a bandwidth increase of 1000 time current spectrum allocation. It is a high bandwidth HF digital channel that can match SATCOM information throughput at a reduced cost and vulnerability. RF waves in the HF band (3-30 MHz) are unique. When transmitted into the ionosphere they are refracted (bent) back to earth thousands of kilometers downrange. However, the ionosphere is an inhomogeneous, anisotropic, non-linear time-varying environment. Fortunately, modern communication techniques can adjust to the ionosphere's dynamic environments. This research provides evidence that the concept will work in the dynamic ionosphere environment. Using a precision modeling tool for ionosphere ray tracing shows wideband channel paths 24/7. Simulations show that an HF agile communication ultra-wideband system can significantly improve throughput.The Virtual SATCOM system starts with a large active electronic scanning array of log periodic antenna elements that focus the communication signal into a 1-degree beam and steers the beam onto mobile platforms, (ships, aircraft, etc.). High power and wide bandwidth of the signal enable high-speed data. This steerable aperture is like radar designs except that the transmitted signal carries information to the target or receives information from the target. This is exciting research that can reduce cost and increase access to long-range high data rate wireless communications.