Design and implementation of a Deep Space Communications Complex downlink array

This paper describes the design and implementation of an array system that includes a frequency domain beamformer that will coherently combine the downlinked signals from up to eight inputs at each of NASA's three Deep Space Communications Complexes (DSCC). The array signal processor digitizes inputs with an intermediate frequency (IF) bandwidth of 100 to 600 MHz, coherently combines the inputs digitally, and transforms the combined waveform back to analog. Real-time correlation measurements are used for delay and phase calibration, allowing the system to adjust for atmospheric variations. A Downlink Array system is operational at each DSCC. Initial results from passes with the New Horizons spacecraft are presented and system performance is analyzed.