| Description |
DESOS (Data Exchange Simulator in Orbital Scenarios) models over the whole repeat-cycle of a Low-Earth-Orbit mission the acquisitions of the scientific instrument embarked aboard the satellite and the respective downlink communication toward the set of identified ground stations.
Given the orbital parameters and the state vector of the spacecraft (imported for instance from STK) different scenarios can be automatically generated for what concerning the acquisition stage, in terms of data rates (related to operative modes), number of active polarizations, strategies applied over land/overseas, as well as the number of downlink channels used, their rates, the position of selected ground stations, the availability of near-real time modes. With this scenario setup, the simulation yields a complete sequence of acquisitions and downlinks during contacts at a real data packets level, allowing to analyze the instantaneous on-board memory occupancy and data latency. The aim is to support the design stage of satellites subsystems which are devoted to sustain the high speed data flow incoming from the instrument, to store it temporarily according to the FIFO paradigm and then to send it to ground only during contacts, typically at a lower speed.
DESOS enables to monitor the effect on the complex system of all these parameters since even a slight variation on one of them turn to be critical, resulting in an non-stationary scenario and consequently causing the required memory to blow up.
Content:
- DESOS.mdl: the main model.
- DESOS_settings.m: the configuration script (called by the model).
- PlotTimeline.m: plots the simulation results (called within the model).
- GenInputData.m: given the satellite state vector (stored in OrbitalData.mat) produces input data used by the model in accordance to the defined scenario (acquisitions data rates and instruments modes and contacts with ground stations).
- NumOfContacts.m: computes over the whole repeat-cycle the number of contacts, given the GS scenario.
- OrbitalData.mat: contains the orbital state vector of the satellite (here an example is given) as imported from tool such as STK, along with a proper set of polygons describing the geo data used for the calculation.
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