#preciseinorbit
ASTROFEIN ACS Test Bed
Testing the entire attitude control system of a microsatellite is a complex step in the verification process. Software-in-the-loop simulations (SILS) and hardware-in-the-loop simulations (HILS) are established test methods for this.
End-to-end testing has many advantages. Utilizing the experience from various satellite projects, ASTROFEIN has designed and realised a new type of ACS test stand (attitude control test stand) for small and microsatellite buses.
Features of the ACS Test Bed
- Mounting platform on an air bearing table allowing free 360° rotation around the vertical axis and 20° – 30° rotation around the horizontal axis
- High-precision in-orbit magnetic field simulation
- Electronic centre of gravity calibration (CoG)
- Adjustable and movable sun simulation
- WLAN command interface
- Safety mechanisms for smooth operation and installation
- Power supply for the test object
Complex simulations possible
With this test bench, a complete end-to-end verification of ACS systems for mini and micro satellites with high target accuracy, including long-term tests, is possible. This test bench is an ideal extension of software-in-the-loop and hardware-in-the-loop testing, taking into account the specific design and testing requirements.
Air-bearing table and platform
By using a high-precision air bearing and non-contact calibration of the air gap, the disturbance forces along all three axes can be kept low, comparable to the in-orbit dis-turbance torques of lower Earth orbits. In addition, the air bearing table is equipped with a safety mechanism that serves to protect the air bearing.
The platform consists of a mounting plate with a mechanical interface for the DUT, a CoG calibration system, the power supply and various equipment.
GNSS and star image simulation
The GNSS simulation consists of a hardware and software component as well as
the remote connection to the control software of the test bed. The GNSS simulator can support all current GNSS signals, including GPS, GLONASS, Galileo, Bei-Dou-2, WAAS, EGNOS, MSAS, GAGAN, SDCM, QZSS and IRNSS.
This extension to the ACS testbed enables the simulation of sensor inputs
for a star tracker and the integration of a star tracker into the ACS hardware-in-the-loop test environment. The Star Simulator can deliver signals for up to four optical heads simultaneously for this purpose. The system simulates stars, planets, sun, moon, scattered light and protons.
Reference system
The external reference system, based on 3D motion tracking, can be used to measure the
position of the platform and the test specimen independently of the simulation. The position of the platform is visualised in the test stand control software and generates inputs for the optional star simulation.
Additionally, the position can be logged together with the simulation data.
NanoSat Test Bed
ACS testing of CubeSats requires a different testing approach, therefore the NanoSat Test Bed was developed featuring:
- Smaller air bearing with ultra-low disturbance torque
- Full satellite mounting and testing
- Integration support
- Very low added MOI to test object
- For CubeSats from 3U to 16U in different orientations
The NanoSat Test Bed can be a stand-alone system or an Add-on to the ACS Test Bed.