A novel, on-board satellite spread spectrum correlator

Currently, there is much research activity in the area of satellite on-board signal processing. This interest stems from the potential to use the space segment as more than just a transponder. On-board processing would improve the overall link budget and allow such features as signal re-routing to be exploited. Typically, most multiple access schemes to the satellite use either time or frequency division techniques. However, spread spectrum multiple access techniques are gaining in popularity and can, in certain instances, provide a viable alternative to the above methods. As with any spread spectrum system, the implementation of the correlator dictates, to an extent, the overall system performance. This paper describes a novel implementation of the correlation function which would be suited to space payloads and in addition considers the various design constraints and benefits. It then reports on the experimental results obtained using a prototype device operating in the C-band region with a spreading code rate of up to 500 Mbit/s. Implementation of the design in high temperature superconducting (HTS) technology is then discussed and results for an HTS delay line fabricated on a 50 mm diameter wafer presented