Formation Flying (FF)
Although recent FF research did not reach the commercial domain, the complexity of large swarm of autonomous satellites deterrents commercial companies. S3NET results offer new and simple design approaches reducing the complexity of the FF. Utilizing natural forces to reduce fuel consumption can reduce costs, and making FF technology more accessible can reduce mission costs.
Optical
In S3NET, small and inexpensive sensor missions in LEO orbit for EO were studied, in order to select representative mission scenarios to investigate in terms of applications. Specific methods to process satellite data were defined and algorithms were developed to cope with the user needs. Co-registration methods, applied to multi-scale and multi sensor data, on-board data reduction through cloudy pixels identification and data compression techniques were analysed. Enhancing on-board performance of satellites and algorithms were developed.
SAR
In the future, space borne SAR missions will fly in close formation, using companion receive-only satellites for (single-pass) interferometric sensing or splitting/extending their synthetic aperture among different satellites. Onboard image formation was investigated, to create realistic benchmarks and determine feasibility. For bistatic SAR imaging employing companion satellite synchronisation and image formation algorithms were developed and integrated into a bistatic SAR scene simulator, a valuable tool for assessment of future mission concepts intended to enlarge the number of scientific observables of SAR missions.
Computing
S3NET firstly created a scalable software-managed high-performance, low-power hardware system employable in space, comprising of multiple high-performance space grade DSPs and off-the-shelf space-validated processors. Secondly, S3Net created a demonstration of software applications and automatically tuned software kernels, for determination of efficient utilization of hardware. This will cause a shift from processing in ground stations to on-board processing due to major cost savings.
Communication
Due to challenging requirements on flexibility/versatility in swarm structures, regarding e.g. number of satellites, topology with a master satellite, distance between satellites, static/dynamic constellations, in principle all parameters relevant to communications schemes were studied.
Adoption of approved techniques from terrestrial cellular networks also wireless sensor networks offered promising solutions to ensure a high quality of service even for bigger and/or ad-hoc satellite swarms.
