STI Remote Terminal Unit (RTU)

The cPCI-Serial-Space based Remote Terminal Unit (RTU) is designed to collect data from different avionic sensors and to control several avionic actuators.

The main part is a cPCI-Serial-Space based IO-Module that can be used centralized inside an onboard-computer (e.g. small satellites) or decentralized in a RTU (large satellites with distributed I/O’s).
The RTU is scaleable by using one or more I/O-modules. Based on this concept also cold- and hot redundancy architectures can be realized.

A dual core LEON3 processor provides enough processing power to perform pre-processing of sensor data.

Based on STI’s Core Avionics concept, the RTU provides also all protected supply voltages necessary to power the connected avionic components.

SpaceTech cPCI Serial Space IO Module 6U Engineering qualification modelcPCI-Serial-Space IO-module, 6U, Engineering and qualification model

Remote Terminal Unit (RTU) key features

  • Analogue and digital standard interfaces
  • LCL protected supply voltages to power avionic or payload components
  • Switched power outlets for heaters and coldgas thrusters
  • Dual Core LEON3 processor, also usable for data pre-processing
  • Connection to an onboard-computer via CAN-Bus or SpaceWire
  • Standardized IO-module based on cPCI-Serial-Space standard

SpaceTech RTU architecture IO Module exampleRTU architecture I/O-module example

Interfaces to external components (e.g. avionic components):

Interface Type  Channels
 PT1000 interface  28
 Analogue voltage input  8
 Analog input resistive pressure transducer  2
 Supply voltage resistive pressure transducer  2
 Discrete digital input  2
 Discrete digital output  4
 Supply voltage, analogous +/-5.. 10V  1
Spacewire interface  2
UART interface (TX+RX)  5
LCL protected power outlets  3
Current outlet  2
Pressure valve outlet  10


The IO-module was developed within the “Onboard Computer System Architecture (OBC-SA) project which is cofounded by the German Federal Ministry of Economics and Technology.