Overview of recent ESA/ESOC patents
The Advanced Operations Concepts Office at ESOC has filed five patents since 2009 in the areas of housekeeping data mining and compression. This page gives a brief oversight of each invention. More detailed information can be found using the links.
DrMUST: Automating the first steps of anomaly investigation
Once engineers have realised that an anomaly has happened, they face the problem of identifying the possible causes and other effects of this anomaly. DrMUST performs pattern matching to find similar behaviours across history (years) and correlation analysis to find which other parameters (out of 20 000) are involved in a given anomaly. DrMUST can be used not only for anomaly investigation but also to perform characterisations.
DrMUST is currently used by Venus Express and Planck both for pattern matching and correlation analysis. Flight Control Team reports 20% – 30% effort reduction in performing anomaly investigation (the other 70% - 80% effort is taken by taking corrective and preventive actions such as modifying procedures).
DrMUST uses speech recognition techniques to find similar patterns in order to cope with small deviations in the behaviour (in the same sense that the same word is spoken differently by two different speakers). Regarding the correlation analysis we have developed a robust technique that finds which parameters are somehow involved in a specific situation (e.g. anomaly, characterisation). The ESA Patent Group has decided to protect DrMUST by filing a patent application in the European Patent Office.
Novelty detection: A new telemetry monitoring paradigm
Being able to quickly identify anomalous behaviour allows reduction of downtime and maintenance of spacecraft health. The current approach built in our Mission Control System is to use out-of-limit checks. However, many behaviours are anomalous even if they are within limits. Novelty detection is a new monitoring paradigm that allows to detect unusual behaviours in telemetry parameters. Unusual behaviour is usually a signature of anomaly in their way to develop. The novelty detection monitoring approach requires very little engineering knowledge as it learns from given examples of nominal behaviour. It also features very seldom false alarms and is complementary to the out-of-limit paradigm.
The Novelty Detector has been validated with Venus Express, XMM and Cryosat2 anomaly cases. The Novelty Detector managed to detect the anomaly way before the out of limits checks did. In some cases, these anomalies were not even detected by the out of limits check. Flight Control Engineers check the Novelty Detection results daily as part of their monitoring tasks.
The monitoring technique based on Novelty Detection uses outlier detection techniques based on density. The assumption is that a new behaviour is often the signature of an anomaly in the way to develop. The ESA Patent Group has decided to protect this novelty detection based monitoring technique by filing an international patent application.
Fractal resampling: Enhancing observability on ground for the same or even less bandwidth
On-board observability depends on the sampling rate used to perform on-board measurements. The fractal resampling technique allows high sampling on board while sending very little data that can account for the most interesting information. This separation between data and information allows gaining on-board observability while reducing bandwidth requirements. The fractal resampling technique is currently used to enable data plotting for online applications.
Fractal resampling has been prototyped to demonstrate its feasibility. At the moment it is being used as a lossy compression technique to enable web plotting clients.
The Fractal Resampling technology takes inspiration from the way 3D fractal terrain is generated in video games. We reverse the process starting with a given time series (e.g. in fractal terrain terms, the time series is the 'mountain'). The ESA Patent Group has decided to protect this fractal resampling technique by filing a patent application in the European Patent Office.
POCKET Compression: How to get ten times more information in your real-time data stream with minimal changes
A problem with most compression techniques is that they require a certain amount of data to be stored before the block can be compressed efficiently. This introduces latency onto the link and makes them unsuitable for real-time control where typically small packets are generated and sent to the user as fast as possible. POCKET is a unique method that can compress individual packets so fast that latency is not noticeable. In fact, in some cases, it even decreases the link latency as the time saved in transmitting a smaller packet more than compensates for the time taken to compress it!
POCKET has been tested using real spacecraft housekeeping data and was found to compress significantly better than ZIP and significantly faster. Average compression ratios of 3 to 20 have been achieved depending the mission. The result is a simple method that simply compresses packets as they are generated and outputs smaller packets. These can then be decompressed on the other end before being injected into a legacy control system. Hence the system impact is minimal.
POCKET has been prototyped and validated on on-board hardware (LEON2 processor) as part of the Proba-3 mission. An end-to-end system is concurrently being bread-boarded as part of an ARTES 5.1 study for use on telecommunications satellites. A TRP study will start soon on using it for remote control of robots. The ESA Patent Group has decided to protect POCKET by filing a patent application in the European Patent Office.
Packet Reader Compression: A simple way to compress on-board stored data
It is commonly believed that HKTM packets do not compress well. However, we have developed a lossless compression technique that provides massive data reduction. It is so simple that it can be implemented on board. The packet reader compression technique groups packet of the same type and reads them using the binary transposed feed, which experiences far less transitions than the traditional feed. This allows use of very simple and efficient compression algorithms (e.g. Run Length Encoding).
The packet reader compression technique has been validated on ground with satisfactory results (e.g. only 14% of data needed for all HKTM Rosetta packets). It has been prototyped and validated on on-board hardware (LEON2 processor). The packet reader compression technique has been identified as enabling technology for the Mars atmospheric sample return mission.
The ESA Patent Group has decided to protect this Packet Reader Compression technique by filing a patent application in the United States Patent and Trademark Office.
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Last update: 12 April 2013