Current ground-based tracking systems at Air Force test and tracking ranges require transmission of a variety of signals from rotating platform to fixed control center. At the moment, the task of signal rotating-to-fixed (RTF) transmission is exclusively handled by cable wrap structures, which provide small angular range, low speed, and are inconvenient to use. To solve this problem. Physical Optics Corporation has investigated an advanced electro- optic hybrid rotary joint (EOHRJ) technology for multiple channel RTF signal transmission. The developed EOHRJ provides the following features. First, it includes a unique two-layer electrical sip ring. This ring is able to accommodate hundreds of transmission channels, including electrical power, control, feedback, and low speed data signals. Second, it uses a unique optical fiber slip ring. This ring, by incorporating electrical time division multiplexing and optical wavelength division multiplexing technologies, is able to provide multiple channel, high data rate (over GBPS), and bi-directional signal transmission. Third, the three-layer overlapped EOHRJ, meets particular military application demands and is designed to be reliable for operation in harsh environments operation, adaptive to stringent size requirements, and accommodating to electrical and mechanical interfaces of current tracker systems.