A Flexible and Robust Spread Spectrum System for TT&C and Satellite Payload Control and Configuration: A Study Case

Aim of the present paper is to show the activity performed and related results and conclusions obtained in the preliminary design of a spread spectrum link for the protection of the satellite telecommand (TC) and payload control and configuration (PCC) links. This becomes fundamental for the telecommunication satellites and their supported networks in view of the growth of the technologies and, consequently, of the pervasive utilisation that they have today in the commercial (civilian) market. Satellite Telecommunication (SATCOM) access is ready to abandon the only utilisation as conventional broadcasting relay for the digital television or simple data feeder link to approach a similar Internet utilisation as possible network node and, even more for the wideband mobile applications and services (on aircraft, trains, ships etc.). Proper operation of such networks, mainly for these utilising emerging technologies and/or utilised in new application contexts, depends on a full availability of satellite TT&C and payload control and configuration (PCC) links at any time. Thus, these links have to be protected against unintentional as well as intentional interference. Today, this protection can be achieved by spread spectrum technology and a robust design of the receiver front end of the satellite. In addition, spread spectrum techniques complement authentication and encryption processes and remove some of their vulnerabilities. To implement the objectives above mentioned, the activity here described has been carried out initially identifying the geo-stationary service areas, i.e. Fixed, Broadcasting and Mobile Satellite Services (FSS. BSS and MSS) ones, two significant scenarios have been identified: (i) SATCOM for Unmanned Aerial Vehicle (UAV) systems, representative of the MSS and (ii) IP Routing on-board Satellite (IPRoS) that is the scenario representative of the Fixed Satellite Services (FSS). For what concern the Broadcasting Satellite Services (BSS), some suitable considerations have reduced the interest of the proposed technology for this satellite service category. The paper after the two mission definition, define a first scenario for the anti-jamming implementation. The scenario definition is used as input to define a suitable jamming model necessary for the following simulation activity. After this initial activity, defining mainly the mission environment, the paper describe the results coming from the analysis and definition phase mainly for what concern (i) the available bandwidths and the ability to interoperate without interfering with the satellite network being controlled for the frequency bands being used by commercial satellites, (ii) the expected levels of intentional and unintentional interference, (iii) the spread spectrum signal structure, (iv) the signal acquisition and tracking aspects and the technical aspect for the RF front end and the integration with the telecommunications payload and platform, considering the required signal processing complexity including data rates adapted to the instantaneous interference environment. All these items have been supported by developing a suitable simulation model verifying the performance of the link design and the signal processing in presence of significant interference. The activity has been concluded with an effectiveness evaluation summarising in an integrated scenario where several technical and market aspects have been considered and analysed in view of a future commercial development of the proposed system.