Ground Segment

A single Myriade ground control segment shared with all scientific microsatellites from the Myriade series developed by CNES. It has a capacity to operate up to 7 satellites executing five different scientific missions. Some elements are shared with the Proteus ground segment. This ground control segment is called MIGS for MIcrosatellite Ground Segment. It is operational since Demeter.

The MIGS reference architecture includes the following elements:

• The two S-band "Icones" multiseries station (TTCET) network developed by ELTA and compatible with the Proteus and Myriade series. One station is located in Aussaguel (near Toulouse) and is CNES property. The second station is located in Kiruna and belongs to SSC (Swedish Space Corporation). These stations are linked to CNES via a satellite link with a 256 kb/s rate (and a back-up ISDN link). The stations provide the command and control link (TM/TC) as well as reception of science telemetry. Since mid-2006 this "Icones" network was integrated into CNES' 2-GHz station network. For missions from Picard and onwards, all 2-GHz station in the network (including TTCET) were able to upload TM/TC.

• The Myriade Command Control Centre (CCC) is based on a common platform for the Proteus and Myriade series. It includes:
  
  • A multi-mission Nominal Control Centre.
  • A MIP Control Centre to develop and test the operational procedure, train the operational teams and rehearse operations of new satellites in preparation for launch. After launch the switch to the nominal CCC was then performed to make room for new missions.
  • A Test Control Centre from which command/control tests are perfomed for in-orbit satellites as well as ground software commissioning and regression testing.
  • Myriade and Proteus CCC common facilities (back-up, time, centralized planning of TTCET passes and designation of TTCET stations).

• The X-band Telemetry Earth Terminal (TETX) designed to receive the high-rate telemetry. This station was shared between Demeter and Parasol and will potentially be used by Taranis and is dedicated to Myriade. This station was developed by SMP. It is located at CNES' Toulouse Space Centre. It is based on a low-cost SPOT Light Station (SLS).

The MIGS provides interfaces with the elements specific to each mission:

• A technological mission centre centralizing technological operations for Demeter (COA, TMHD,...). It is also located at CNES in Toulouse.
• The scientific mission centres. For Demeter, the scientific mission centre is located at the LPCE environmental and space physics and chemistry laboratory in Orléans. For Parasol it is composed of the CMS co-located at CCC and which provides level 0B processing, and the CPP3 which performs upper-level processing. The CCC interfaces with the mission centres via a specific software component for each mission: G4 (developed by CS SI). A new scientific mission centre is added for each new mission.
• The mission centres external to CNES exchange data with the MIGS (mission telemetry, TC plans, auxiliary data) by FTP via the SEF data server (Serveur d'Echange de Données). This server is located at CNES and was developed by CNES.
• The CCC also interfaces with CNES multi-mission facilities (Operational Orbitography Centre (COO : Centre d'Orbitographie Opérationnelle) / 2-GHz network), particularly for the first acquisition phases during the launch.

The CCC was developed by CNES. The software groups were developed by:

• T3S: G1 (TM/TC interfaces, real-time RM/RC, IP contacts with the TTCET and TETX).
• CS SI: G3 (archiving, pre-recorded time survey, FTP contacts with the S-band and X-band stations), SWWW (data server), G4 (interfaces with the mission centers - specific for each mission), DRPPC (quicklook display), Agenda (operation automation), CCC and MIGS integration help.
• Thales IS: G2 (space flight dynamics, specific for each mission).

The MIGS and CCC internal and external interface format is standardized in a Myriade/Proteus generic document (particularly the interfaces between the MIGS and the mission centres). The exchange concepts are thus always the same to provide maximum common functionality between missions.