Design and implementation of the deep space interferometry DBBC sub-system

The need for high accuracy navigation in deep space exploration has triggered the development of interferometry technology in deep space TT&C. This paper describes the design and implementation of a new DBBC sub-system of the deep space interferometry digital backend. The DBBC sub-system can process two IF analog signals with 512MHz bandwidth and output at most 16 channel baseband signals with bandwidth from 16MHz to 1kHz selectable. In order to strengthen international cooperation, the DBBC sub-system is special designed to support both current mainstream data format, that is real baseband output mode with Mark5B format and complex baseband output mode with REDF (Delta-DOR Raw Data Exchange Format). The two modes can be switched randomly on runtime. Two new baseband conversion methods are proposed for the two modes respectively. One is improved uniform channelization with the orthogonal mixing method, the other is multi-channels parallel NCO based orthogonal mixing method. Both methods can perform full spectrum processing of IF signal efficiently. Any spectrum can be selected from the IF signal with a tunable frequency resolution of 10Hz and down-converted to baseband with bandwidth range from 16MHz to 1kHz.