Since spacecrafts need to be equipped with radio subsystems for carrying out communication with the Earth and execute orbit determination measurements, there is the possibility to exploit instrumentation already present onboard to perform radio science experiments. As a matter of fact, most of radio science subsystems are not completely independent instruments and scientific experiments are carried out using radio links belonging to the spacecraft Telemetry, Tracking and Command (TT&C) subsystem, in combination with dedicated radio science instrumentation. Initially conceived as an exploratory tool, radio science techniques have provided considerable knowledge of planetary atmospheres and ionospheres, rings, and gravity fields, some of which were originally unanticipated. Radio Science investigations can be broadly divided into gravity, radio occultation, bistatic radar and relativity experiments. The typical scenario for the above experiments consists in carrying out spacecraft (S/C) tracking in two-way (GS-S/C-GS) or in one-way (S/C-GS) mode. However, in the recent years the possibility to reverse the order of one-way observations (which would then become GS-S/C) have arisen, because of the significant increase of computational power of modern space-qualified DSPs. The paper provides an overview of the main uplink (GS-S/C) radio science investigations including gravity, radio occultation, bistatic radar and relativity experiments. The main requirement relevant to space segment receiver as well as ground segment transmitter are addressed for each radio science investigations. An effective method for assessing feasibility and design of radio science experiments in novel configurations is to simulate radio wave signal propagation from emitter to receiver, calculating deflection angle, frequency shift, and attenuation strength. As we will show in this study, we developed a numerical tool to carry out such simulations. Finally the on board receiver top level system architecture including baseband filtering performance as well as on ground transmitter and antenna issues are briefly discussed.
On-Board Radio-Science: Science Requirements, System and Architectural Trade-Offs and Preliminary Performance Analysis
CINARELLI, DAVIDE;PALLI, ALESSANDRA;TORTORA, PAOLO;
2010
Abstract
Since spacecrafts need to be equipped with radio subsystems for carrying out communication with the Earth and execute orbit determination measurements, there is the possibility to exploit instrumentation already present onboard to perform radio science experiments. As a matter of fact, most of radio science subsystems are not completely independent instruments and scientific experiments are carried out using radio links belonging to the spacecraft Telemetry, Tracking and Command (TT&C) subsystem, in combination with dedicated radio science instrumentation. Initially conceived as an exploratory tool, radio science techniques have provided considerable knowledge of planetary atmospheres and ionospheres, rings, and gravity fields, some of which were originally unanticipated. Radio Science investigations can be broadly divided into gravity, radio occultation, bistatic radar and relativity experiments. The typical scenario for the above experiments consists in carrying out spacecraft (S/C) tracking in two-way (GS-S/C-GS) or in one-way (S/C-GS) mode. However, in the recent years the possibility to reverse the order of one-way observations (which would then become GS-S/C) have arisen, because of the significant increase of computational power of modern space-qualified DSPs. The paper provides an overview of the main uplink (GS-S/C) radio science investigations including gravity, radio occultation, bistatic radar and relativity experiments. The main requirement relevant to space segment receiver as well as ground segment transmitter are addressed for each radio science investigations. An effective method for assessing feasibility and design of radio science experiments in novel configurations is to simulate radio wave signal propagation from emitter to receiver, calculating deflection angle, frequency shift, and attenuation strength. As we will show in this study, we developed a numerical tool to carry out such simulations. Finally the on board receiver top level system architecture including baseband filtering performance as well as on ground transmitter and antenna issues are briefly discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
