New image stabilization could improve exposure times for low light images

The demand for higher image resolution for Earth observation and science missions is driving complex designs not only at payload level but also at platform level.

Very accurate sensors and other high-cost means to compensate platform perturbations are being developed and becoming critical for up-to-date missions, possibly even becoming show stoppers for future demanding missions.

A recently closed TDE activity with Thales Alenia Space in France has developed a high accuracy image stabilization technology. The activity assessed the stabilization of the two ESA mission scenarios to secure and improve their performances.

The activity focused mainly on two mission scenarios: the GEOHR potential Earth Observation geostationary satellite and a hosted payload scenario. It found that two types of systems were suitable for these:

- Large angle tilt mechanisms, which provide a contiguous smooth scanning motion involving a large angle of motion and low frequency

- Fine tilt angle mechanisms: involving small strokes these systems can be controlled at very high frequencies (hundreds of Hz).

Several algorithms have been tested for each scenario using COTS products that ensured a good fit in terms of size and performance. The estimation of the motion between two image frames was considered a trade-off compared to the technology’s complexity, or the costs of on-board calculation and processing time.

The activity also assessed how this new image stabilisation system could be implemented onto existing telescopes, and then, taking into account the various trade offs, found the best architecture for the technology.

Overall, the additional cost and complexity of such a system compared to traditional stabilisation using high grade sensors and actuators means it is not a viable alternative for current systems.
But, the new technology meant significantly longer exposure times could be achieved, enabling observations in low light conditions, something that former designs could not perform.

All documentation for T105-501EC was received in June 2020 and can be found on TEC-DMS.