MTG. Scan assembly electronics (SCAE)

The main function of the MTG (Meteosat Third Generation) scan assembly electronics (SCAE) is to provide a controlled, high precision scan and sweep movement of the mirror of the main telescope.

To achieve this, the electronics house the following functions:

• Accurate control and input of the dual axis motors: N/S (North/South) and E/W (East/West)
• Control and input of blocking/unblocking motors of the mechanism
• Monitoring and fault management
• Communications with the spacecraft
• Conditioning and internal distribution of power
• Data processing and management 

Most of these functions take place in SW developed by SENER on a LEON2 platform. 

The unit consists of a nominal and a redundant section, both identical. Each of these sections houses the modules:

• Modules:
• DC/DC converter
• Backplane, to interconnect modules
• Processing module
• Acquisition and motor drive module 

• Mass: 5 Kg
• Size: Length: 247; height: 150; width: 175
• Thermal power:
  • Operating range: -20ºC: +50ºC
  • With start at – 25ºC
• Redundancy: Two fully redundant sections in a single box.
• Input: Input bus: +28 V
  • Power consumption: 25-30 W (approximate values according to the operating mode)
• Observability and controllability:
  • Each section has various 1553 MilBus and SpaceWire communication buses for control and monitoring and dispatch of data, respectively
  • The unit implements a reduced set of PUS services
• Features of the processing module:
  • Processor: LEON2 AT913E
  • Link SpW up to 80 Mbit/s (with capacity of 200 Mbit/s)
  • PROM memory: 32 kB
  • EEPROM memory: 4Mbit
  • SRAM memory: 5 MB (including fault detection and correction (EDAC)