This paper investigates the performance of a satellite communication system which the onboard receiver regenerates the uplink pseudonoise (PN) ranging sequence. Using phase modulation, the PN ranging signal is transmitted together with the telecommand signal in the uplink and the telemetry signal in the downlink. Various ranging sequences are taken into consideration and tested prior to final international adoption. The reciprocal interference among telemetry, telecommand, and ranging signals is evaluated in terms of bit error rate and ranging phase acquisition time.

This paper discusses a new implementation of a Gaussian minimum-shift keying (GMSK) modulator and demodulator on the European Space Agency (ESA)'s common deep-space receiver-the Intermediate Frequency Modem System (IFMS), which is a software radio based platform. The GMSK demodulator is needed for ESA's deep-space and near-Earth missions, starting with the Herschel-Planck satellites in 2008. The implementation requirements and hardware restrictions from the IFMS lead to the need for a significant simplification versus the optimum demodulation approach. In part, this can be achieved by using a demodulator based on the Laurent decomposition, yet further simplifications and changes to obtain a feasible implementation were necessary. The presented GMSK demodulator was directly implemented on the existing IFMS receiver without requiring any hardware changes. Measurements with the demodulator showed only a marginal technical degradation in the order of 0.1-0.3 dB for the chosen approach. Furthermore, for testing purposes, a GMSK modulator was implemented on the same platform.

The European Space Agency (ESA) is today autonomously flying three interplanetary missions: Rosetta traveling to the comet Churyumov-Gerasimenko and the two orbiters Mars Express and Venus Express. The capability of supporting these and future deep-space missions is the consequence of a farsighted decision taken in 1996 to expand the ESA network of 15-m tracking antennas into the deep-space domain. The ambitious plan to provide around-the-clock coverage to all ESA interplanetary missions is almost completed: two deep-space antennas, located in New Norcia (Australia) and Cebreros (Spain), have been in operation since 2002 and 2005, respectively, while a third antenna is planned for 2011. This paper presents the two existing antennas starting from the underlying system requirements originated from the Rosetta mission, which was the most demanding in terms of required performance. The selected architecture is then described, followed by a detailed discussion about the critical performances that play a major role in deep-space support and the associated design issues.

A turbo code has been included in the new Consultative Committee for Space Data Systems (CCSDS) channel coding standard for space telemetry. Many future missions with critical link budgets will benefit from its large coding gain. In this paper, the properties of this turbo code are analyzed for symbol synchronization recovery, where the transition density is essential. Key parameters like transition/symbol probability and run-length distribution are studied and compared against practical requirements. Critical working conditions are considered separately and discussed. It is shown that, thanks to the interleaver action, turbo-encoded sequences have very good properties in terms of randomness.

The tool used to simulate the European State Agency's (ESA's) S/X-band Telemetry, Tracking and Command (TT&C) Ground Stations Network ground and space segments is discussed. The building blocks it is made of and the various modulation and code schemes it encompasses are described. A detailed description of how the ESA standard tracking system is simulated in order to evaluate its impact on the telecommand and telemetry channel performance and to determine the tracking performance as well is given. A selected sample of both measurement and simulation results is presented.>