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Advanced Dual Band Apertures for improved early warning and space situational awareness missions


OBJECTIVE: Advance dual band aperture designs including T/R modules to increase early warning and space situational awareness radar system capability. DESCRIPTION: Early Warning Radars are operated by 21st Space Wing squadrons for missile warning and space surveillance. This is a long- range, phased-array radar system. It is designed to detect and characterize a sea-launched and intercontinental ballistic missile attack against the United States. The system also has a secondary mission of Earth-orbiting satellite detection and tracking. Information received from the radar systems is forwarded to the United States Space Command's Missile Warning and Space Control Centers at Cheyenne Mountain Air Force Base, Colorado. The radar system is capable of detecting and monitoring a great number of targets that would be consistent with a massive submarine-launched ballistic missile (SLBM) attack. The system must rapidly discriminate between vehicle types, calculating their launch and impact points in addition to the scheduling, data processing and communications requirements. The antenna of the existing radar system consists of multiple planar phased arrays operating at the UHF band. It has been recognized that a dual band system could significantly enhance the present system capabilities. The UHF band provides long range capability due to low propagation losses, and the higher band such as X-band offers high resolution and better tracking accuracy (range resolution better than 10 m and cross-range resolution better than 3 km for objects at a range of 2,000 kilometers). This initiative will identify the performance benefits and potential challenges of a single band versus a dual band radar system (UHF/X), for EW and SAA missions. Performance objectives include wide area volume search, tracking, ballistic missile defense discrimination, and space object surveillance. The contractor is encouraged to perform a first order system analysis including any associated constraints in spectrum access or interference in the proposed bands. The merits and challenges associated with an integrated dual band phased array aperture have to be included in the analysis. The ability to field the capability in the 2018+ time frame is a consideration, and therefore the technology readiness level of the technology will be an important factor. The current documented targets should be assumed, but the ability to address emerging threats must also be considered. PHASE I: Perform a first order system study and recommend a second band for future EW/SSA radar systems. Design a dual band array considering latest technologies as well as retrofit (and/or add-ons) of the existing structures. Define the respective T/R module technology and RF/Digital beamformers. Predict the system performance improvements relative to the existing single band radars. PHASE II: Based on Phase I study, perform a detailed analysis and design of a small sub array. Fabricate, measure and characterize the subarray. Based on the measured data, assess the full system performance. Identify the technology readiness levels at subsystem and system level. Provide recommendations on how to further mitigate risks, and develop rough cost estimate. PHASE III: Build a scalable sector of the array that would allow the measurements of the radar performance. The array performance, in conjunction with the radar functions will be measured in a far field range. The manufacturing and TRLs will be updated and cost inputs refined. REFERENCES: 1. Tomasic, B., et al."The Geodesic Sphere Phased-Array Antenna for Satellite Communication and Air/Space Surveillance Part 1"AFRL in-house technical report AFRLSN- HS-TR-2004-031, Jan 04. 2. 3. 4. 5. & mode=form & id=2f3973d6a7d33a330f489cad72702494 & tab=core & _cview=0.
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