One of the basic requirements for patentability is the technicality of the invention. This is the case if the claimed teaching involves the use of technical devices. Mathematical methods and programs for data processing as such are excluded from protection. In its ruling “Aircraft State”, the Federal Court of Justice now had to assess whether a calculation method that differs from the prior art only in mathematical steps is patentable.

The disputed Application deals with a “method for determining an aircraft state”. The idea of the invention is that the highly noisy measurement data, which is also generated at a high clock rate, is processed using a specific averaging method before being processed in a known manner using a Kalman filter.

A system was already known from the prior art in which the data was subjected to arithmetic averaging before Kalman filtering. The only new feature is that the averaging is performed in a different way, namely by determining the center of gravity and radius of an n-dimensional sphere in the n-dimensional parameter space. The sphere should be the smallest possible sphere that includes all measurement points in n-dimensional space.

The German Patent Office and the Federal Patent Court rejected the Application for the following reasons: Compared to the closest prior art, the claimed method differed only in that different statistical quantities (namely center vector and radius of the n-dimensional sphere) were used to represent the individual values than in the prior art. These new features are based on statistical or data modeling considerations, but not on technical considerations. Moreover, it was irrelevant that these non-technical process steps were applied to technical data.

Thus, the invention differs from the prior art only in non-technical features. However, precisely such features should not be taken into account when assessing inventive step. Therefore, the invention was obvious to a person skilled in the art.

The appeal on points of law lodged by the Application with the BGH led to the judgment being set aside.

Referring to the old jurisprudence “Rote Taube” (1969), the BGH is the first to confirm the old principle that patent protection is reserved for the field of technology and that a patentable invention must be a teaching for technical action. Technical action consists of working with the means of natural forces. However, it is characteristic of working with natural forces that the underlying laws are described using mathematical methods. Therefore, mathematical methods are not generally excluded from patent protection. On the contrary, they are certainly eligible for patent protection if they make use of technical means and solve a technical problem. A mathematical method is only non-technical if its application is not related to the targeted application of natural forces.

In the specific case, the BGH states that the claimed method is of a technical nature because it requires the use of technical equipment, namely an inertial system in an aircraft and a data processing system for the Kalman filter.

The arithmetical operations mentioned in the claim represent the application of statistical methods. In the present case, however, they do have a sufficient connection to the targeted application of natural forces. The calculation steps accelerate the further calculations carried out with the Kalman filter and serve the purpose of gaining more reliable knowledge about the condition of the aircraft. Furthermore, this influences the functioning of the system used to determine the condition.

The process steps regarded as non-technical by the Federal Patent Court must therefore be fully taken into account when assessing patentability.

With this ruling, the BGH confirms the patent-friendly approach that mathematical methods and Software are always patentable if the purpose is to influence a technical system.