Advanced Metrology Technologies for Next-Generation Space-Based Radar

As airborne radar missions migrate to orbital platforms, the required size of the RF aperture increases significantly with operating range. This places additional limitations on allowable mass and stowed volume relative to effective launch vehicle options These large physical apertures, high stowage efficiency and low mass requirements promote RF antenna designs with limited mechanical planarity and temporal stability. Large aperture space-based radar (SBR) approaches require some form of metrology to measure and compensate aggregate mechanical and electrical errors in the antenna subsystem. The lack of antenna knowledge limits phase coherence and creates dynamic errors relative to antenna gain, sidelobe levels, beam steering accuracy, and amplitude/phase balance among multiple channel configurations. Collectively, these errors significantly impact ISR performance and must be corrected to achieve operational utility. TSC will develop a RF-based metrology system architecture, hardware design and supporting software algorithms for both monolithic and distributed aperture SBR concepts. The layered metrology architecture will support integration with multiple SBR payload designs. The projected capability of the metrology system (i.e. residual errors) will be assessed with respect to its impact on overall SMTI/SAR mission performance. These coupled metrology-ISR performance models will support integrated trades of metrology, antenna design, and achieved ISR performance.