Community Research and Development Information Service - CORDIS


NetSat Report Summary

Project ID: 320377
Funded under: FP7-IDEAS-ERC
Country: Germany

Periodic Report Summary 2 - NETSAT (Networked Pico-Satellite Distributed System Control)

Multi-satellite systems are currently gaining significant importance, leading to the future demand for coordinated formation control for future applications of fractionated missions based on a larger number of satellites. The NetSat project addresses here the key scientific control questions,being tested in the technical demonstration of a formation of four miniature cubesats in orbit. The achieved progress is documented in more than 50 publications and the NetSat research received recognition by well reputed awards.
Beside general technical challenges in energy efficiency, and robustness of small satellite technology, new technical solutions are necessary in order to provide the required key technology to realize a formation of spacecraft within the constraints of mass, space and power. In particular, challenging enabling technologies concern the inter-satellite communication to enable the autonomous cooperation of individual spacecraft, while adequate attitude and orbit determination and control mechanisms based on mass-efficient propulsion systems are required to prevent the individual spacecraft from drifting apart. Optimal control techniques close the loop to coordinate the relative motion between the satellites autonomously, while new concepts for multi-satellite operations are necessary to allow efficient supervisory control of the entire formation with minimal interaction of the operators.
In the progress of this reporting period, various application scenarios have been studied and exemplary requirements for small satellite formations have been investigated. Miniature sensor systems for navigation have been analyzed, selected or implemented and tested for their utilization onboard the demonstrator mission. The resulting sensor suite is currently integrated into the hard- and software design of the demonstrator to fuse their measurements in order to provide required navigation knowledge for formation control.
Various actuators and control algorithms for precise attitude and orbit control of individual miniature satellites have been analyzed, implemented, tested and optimized. As actuator suite for the demonstrator mission a combination of energy efficient magnetic torquers and miniature field-emission electric propulsion thrusters has been integrated into the hardware design. Specific embedded control software is currently being implemented and tested to operate on the miniature attitude and orbit determination and control hardware.
The link budget for the inter-satellite communication link (ISL) has been analyzed in accordance with the anticipated mission scenarios of the demonstrator mission. As commercially available transceivers turned out to be suboptimal for efficient integration on a miniature satellite, a dedicated transceiver development has been initiated in cooperation with a local company. Required frequency coordination procedures for the operation of the demonstrator mission have been initiated with the international authorities. The hard, and software interface of the ISL is currently being implemented into the satellite design. With the finalization of the prototype hardware, extensive tests will be carried out in the next months to verify the performance of the development.
A concept for efficient multi-satellite operations based on remotely controlled semi-autonomous ground stations combined with autonomous planning and goal based operations onboard the spacecraft has been elaborated and is currently being implemented in software for the ground and the space segment.
Different algorithms for autonomous formation control have been reviewed, implemented, and evaluated based extensive simulations using a specially developed simulation environment for satellite formations. Selected algorithms are currently being optimized for the demonstrator mission. Embedded implementation of the control algorithms will be carried out in the next months.
Simulations on specific formation control aspects for proof of concept and preliminary parameter estimations have been performed. Therefore, an integrated formation simulation environment for detailed analysis of different crucial mission phases and for support of hardware in-the-loop tests on the engineering model is being developed.
The demonstrator spacecraft design is advancing according to the progress of the previous work packages. A comprehensive CAD model of the mechanical design is maintained and corresponding budgets (mass, volume, power) are optimized. First subsystem prototypes are already available and are currently put into operation to be used for embedded software implementation and first hardware in the loop tests.

Reported by

Zentrum fuer Telematik e.V.
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