Optical Rf Communications Adjunct (ORCA)
Program Manager: Dr. Larry B. Stotts
There is a need for high-capacity communications networks for tactical applications. The military needs to transmit and receive video, voice, chat, and other important information simultaneously among various dismounted and maneuver force elements, airborne assets and the upper echelons. This aggregated information is placing increasing demands on the capacities of current military RF systems and applicable military and commercial RF satellite links. The result is that new, unallocated spectrum must be utilized if the projected future military requirements are to be met given the oversubscription of VHF-UHF-L band frequencies. The spectrum regimes that appear to fit these criteria are Free Space Optical and RF frequencies in higher bands such as Ku and Ka.
The DARPA Optical Rf Communications Adjunct (ORCA) prototyping program will build and test a secure hybrid Free Space Optical (FSO) and RF Internet Protocol-based Gateway Network system for tactical reach-back applications. The objective of the ORCA effort is an actual prototype demonstration of a tactical network containing ground based On the Move/At the Halt (OTM/ATH) and airborne nodes. Airborne nodes will be expected to communicate between each other up to ranges of 200 km and with ground nodes up to 50 km slant range. Nominal aircraft altitude is expected to be 25,000 ft. Objective usable data rates for the system include a nominal node to node uncorrected 274 Mbps data rate for the RF portion of the hybrid link and an uncorrected 5 Gbps data rate (or higher is acceptable) for the FSO portion of the hybrid link. Another objective is to complete the ORCA program with a Technology Readiness Level 6 (TRL-6) system and provide a leave-behind capability for users this equipment.
