Internship title: New EUMETSAT GEO Ranging System Feasibility and Performance Analysis
The need to accurately determine a spacecraft’s position relative to its supporting ground station and its intended target is fundamental to space navigation. In its basic form, the range measurement begins with a known ranging signal modulated onto an uplink, retransmitted by the spacecraft, and then detected on the downlink. The round-trip light time associated with this cycle yields a measurement of the range.
In non-regenerative ranging techniques, such as tone ranging for example, the on-board transponder performs phase demodulation and re-modulation of the carrier only. When the ranging signal is turned around or retransmitted by the spacecraft, the uplink noise is also modulated onto the downlink carrier, incurring a path loss thereby degrading the ranging measurement precision.
The Consultative Committee for Space Data Systems (CCSDS) has addressed this issue by providing recommendations for two cases of regenerative ranging, one where ranging accuracy is a priority, and the other where acquisition time is of primary concern. However, this internship will be more focused on the CCSDS recommendation for transparent (nonregenerative) ranging. These recommendations were selected based on evaluating performance in several key metrics, including: range measurement accuracy, acquisition time, interference to telecommand/telemetry, and hardware implementation.
The purpose of this internship is to study and analyse through simulations and ad-hoc software tools the potential performance of the recommended CCSDS PSEUDO-NOISE (PN) Ranging Systems when applied to EUMETSAT’s GEO spacecraft fleet. The new S/W simulation tools (mainly MatLab and/or C++) shall be developed or tailored to allow parameterisation of the different scenarios, including extreme degraded cases.
This internship will provide students with the possibility to put in practice several different signal processing techniques learnt at university.