Verification of Navigation and Control Systems

Vehicle systems can only be tested with restricted degrees of freedom and accuracy of the environmental dynamics before being flown. However, a vehicle’s dynamics can be simulated and its sensors can be artificially stimulated. This is needed to test flight software, hardware components and the interactions between subsystems. The Institute for Space Systems is currently developing a laboratory in which orbit and position control, navigation and control systems can be tested. These hardware-in-the-loop tests can be carried out in two steps:

1. First, the on-board computer can be tested by itself. For each interface, a simulation computer provides the on-board computer with a simulated interface in real time. Additionally, the simulation computer receives information from the on-board computer and may have to integrate this information into the dynamics simulation.
2. Next, the simulation computer creates signals for the sensor stimulators in real time. The on-board computer then interfaces with the actual sensors instead of the simulator.  These stimulators make it possible to test the sensors as well as the on-board computer. 

It is possible to create a system which can test a variety of orbit and position control systems. To adjust for a particular mission, the simulated interfaces can be configured according to most types of sensors and actuators.