Monday, 24 May 2010

T 149/07 – Sophisticated Obviousness

The present decision gives a useful reminder concerning “common general knowledge”. It has also retained my attention because it concludes on lack of inventive step based on a rather sophisticated combination of documents. In a recent post, we have seen that the Boards do accept demonstrations of lack of inventive step based on more than two documents. Here the claim (effective date: 1995) was rejected as obvious over a combination of prior art D1 (1979) and D3 (1988), complemented by common general knowledge (for which D7 (1985) was considered to provide evidence). The fact that D7 also disclosed the drawback of the claimed alternative (its complexity) was considered to have been made obsolete at the date of the claim as a result of ongoing technical progress.

[...] D1 discloses a Fairchild-Automatic-Intercept-and-Response-System (FAIRS) which comprises a central command station controlling fixed or mobile transportable remote sites. The system is intended for carrying out signal surveillance, monitoring, direction finding and accurate location of hostile transmitters.

It was not disputed that D1 represents the closest state of the art showing a system of surveillance according to the precharacterising part of claim 1. [3.1]

The [opponent] considered claim 1 as including a mere aggregation of features independent from each other. In particular, the group of features concerning activation/deactivation and operation mode of the cells ([h], [j] and [k]) could be regarded separately from that pertaining to TOA measurement ([l] and [m]).

This view is convincing. A combination invention would imply a functional relationship between features or groups of features resulting in a combinative effect beyond the sum of the individual effects. Such a combinative effect cannot be identified in the present case at least with regard to the groups of features referred to above. In particular, claimed characteristics of a cell concerning activation, deactivation, communication with the information centre and loading of parameters, on the one hand, and features for determining the bearing of a phenomenon on the basis of a time-of-arrival measurement, on the other hand, are functionally not so linked together that a synergistic effect results from their combination. Thus, when assessing inventive step, each group of features may be considered per se. The [patent proprietor] objected that this approach resulted in a mosaic combination of different features out of their context. This objection, however, is not conclusive in view of the foregoing. [3.2]

[…] D1 is considered to disclose not only the precharacterising part but also feature [i] of claim 1. [3.4]

[…] D3 discloses feature [h] of claim 1.

In the Board’s view, D3 also discloses feature [j] of claim 1. [3.5]

[…] With regard to feature [k] of claim 1, D1 […] discloses that the receivers at each remote site are commanded from the command centre to scan particular portions of the RF spectrum wherein a threat transmitter is thought likely to operate. As soon as a threat signal is detected, signal recognition is carried out, an alarm is registered, a bearing is taken and the alarm is transmitted to the command centre. Thus, the receiver at a remote site operates in an active mode in response to a command from the command centre and reports to the command centre upon detection of a threat signal in accordance with given criteria.

In the light of this disclosure, the Board finds convincing the [opponent’s] submission that a standardized protocol is necessary for the communication between remote receiver and command centre. Thus, the feature concerning the standardized protocol is either implicit to the disclosure of D1 or trivial for a skilled person. [3.6]

Features [l] and [m] of claim 1 concern a TOA measurement on the basis of two cells with synchronised internal time.

In its interlocutory decision […], the opposition division (OD) considered that documents D1 and D3 did not render obvious the use of two different cells for a TOA measurement. In its view, although TOA measurements were known in the art at the priority date of the present patent, a skilled person got no incentive from the prior art to apply this technique to the system of D1. Even if the skilled person tended to introduce this technique, he/she would not consider the claimed solution of providing the bearing of a phenomenon by comparison of signals of two distant cells. On the contrary, the more straightforward way would be to introduce the TOA technique in the setup shown in D1 […], i.e. to rely on a measurement based on two antennas of the same cell, which could be placed far enough to give sufficiently accurate results. Indeed, the use of antennas of two different cells had the drawback that an accurate time determination in both cells was needed. Such a feature, however, was not disclosed, either explicitly or implicitly, in D1. Rather, the arrangement of D1 was based on a single cell and had the advantage that the accurate time determination was not necessary.

The Board would agree with this argumentation on the basis of the disclosure of D1 only. The OD, however, had no knowledge of textbook D7 filed with the notice of appeal.

D7 […] is concerned with the interception of radar signals, in particular with the issue of how to use various receivers in interception applications. Other major topics concern direction finding and location. Chapter 5, which deals in extenso with the issue of emitter location techniques, presents two major approaches. Emitter location estimation using multiple angle-of-arrival (AOA) measurements is the classic approach, the basic idea of which changed little since the 1940s. The time-difference-of-arrival (TDOA) technique is more complex, and its use is more recent and much less widespread. According to the leading-edge (LE) TDOA technique, the arrival time of the leading edge of a radar pulse is determined at a receiver. The difference between the arrival times of the same pulse at two widely separated ground-based sites gives the TDOA with respect to the baseline between the two receivers. This TDOA measurement establishes an iso-delay line on the surface of the earth that passes through the emitter location. A similar TDOA measurement with respect to another baseline establishes another iso-delay line. The intersection of these iso-delay lines determines the location of the emitter (Figure 5-8).

The [patent proprietor] contested that document D7 reflected common general knowledge […]. Moreover, in its view, the outcome of the present case would not be changed by the consideration of D7 […].

Thus, two issues need to be considered. First, whether D7 reflects common general knowledge. Second, whether a skilled person would consider introducing the leading-edge TDOA technique according to D7 into the system of surveillance known from D1.

With regard to the first issue, the jurisprudence of the boards of appeal has defined the common general knowledge of a skilled person working in a particular technical field as being normally represented by the content of encyclopaedias, textbooks and dictionaries on the subject in question (T 890/02 [2]).

Three aspects have been identified for assessing the common general knowledge of the skilled person (T 890/02 [3]). Firstly, the skills of such a person include not only basic general knowledge of a particular field of technology, but also the ability to look up such knowledge in encyclopaedias, textbooks and dictionaries. Secondly, it cannot be expected that, in order to identify this common general knowledge, the skilled person will carry out a comprehensive search of the literature covering virtually the whole state of the art. No undue effort in such a search can be required from the person skilled in the art. Thirdly, the information found must be unambiguous and usable in a direct and straightforward manner without doubts or further research work.

In the present case, the Board does not have any reason for diverging from this jurisprudence that would lead to the conclusion that textbook D7 represents common general knowledge. In particular, it may be expected that the skilled person, designing systems of surveillance such as the one known by D1, would be aware of a textbook like D7 dealing inter alia with radar emitter location by a TDOA technique that represents an embodiment of the present invention covered by the claimed subject-matter. Thus, contrary to the [patent proprietor]’s view, the Board considers that D7 represents background knowledge.

With regard to the second issue mentioned above, the [opponent] submitted in the grounds of appeal […] that D1 described an operational system. At the publication date (1979) of this document and a fortiori at the time the described system was designed, computers with a computational power sufficient for making TDOA measurements on the basis of two cells with synchronised internal time were not yet available. For this reason, the system of D1 relied on AOA measurements. At the priority date of the present patent (1995), however, a skilled person, knowing from D7 that the TDOA technique could be used in systems like the one known from D1, would immediately consider that such a technique represented an obvious alternative to the AOA measurements on which the system of D1 relied. D7 itself prided support for this conclusion. Indeed, AOA and TOA/TDOA measurements were disclosed as two viable alternatives […] that might even be combined […].

The [patent proprietor] did not dispute that the TDOA technique per se was known. What was relevant, however, was its application in a system of surveillance as claimed. No document on file suggested such an application. On the contrary, the complexity of the TDOA technique, which was acknowledged in D7, played an essential role against its application and should be duly considered when contemplating the combination of D1 and D7.

The [opponent]’s submissions are substantially based on the approach that the skilled person was led by the technical progress to consider alternatives to the AOA technique disclosed by D1. This view is not invalidated by the [patent proprietor]’s argument concerning the complexity of the TDAO technique. Indeed, this drawback would be compensated by the ongoing computer progress, on the one hand, and by the improvement in location accuracy that may be achieved […], on the other hand. The former aspect is clearly at the basis of the development of the more recent TDOA approach […], which may regarded as an alternative to the classic AOA approach, as the [opponent] convincingly submitted. It should also be taken into consideration that D7 […] points out that, in an operational emitter location system, the AOA approach will be needed along with the TDOA approach. In a dense environment of emitters, it will be difficult to determine which pulse is coming from which emitter at separated receiver platforms. By using the AOA approach, only those pulses having appropriate bearings need be considered in the TDOA processing. In the Board’s view, this disclosure gives the skilled person a hint at integrating the TDOA processing in the system of D1 rather than replacing the disclosed AOA technique.

Therefore, D7 represents common general knowledge of the skilled person, discloses features [l] and [m] of claim 1, and incites the skilled person to complement the system of surveillance of D1 with these features. [3.7]

In conclusion, keeping in mind the aggregation character of the features of claim 1 of the maintained patent, as mentioned above, the subject-matter of claim 1 at issue lacks inventive step (A 56) in view of documents D1, D3 and D7. [3.8]

To read the whole decision, click here.