Full opinion text
MEMORANDUM OPINION THYNGE, United States Magistrate Judge. I. INTRODUCTION This is a patent infringement case. - On March 3, 2003, Honeywell International Inc. and Honeywell Intellectual Properties Inc. (collectively “Honeywell”) filed suit alleging infringement of its U.S. Patent No. 4,914,436 (“the ’436 patent”) by certain products of Universal Avionics Systems Corp. (“Universal”) and Sandel Avionics Inc. (“Sandel”) (collectively “defendants”). This court has jurisdiction over the subject matter of this action pursuant to 28 U.S.C. §§ 1331 and 1338(a). This court has personal jurisdiction over defendants .because defendants are incorporated in Delaware and/or have been doing business in Delaware. - Venue is proper in this judicial district pursuant to 28 U.S.C. § 1400(b). On March 24, 2003, Sandel filed its answer and counterclaims denying Honeywell’s allegations and seeking a declaratory judgment of invalidity, noninfringement and unenforceability of the ’436 patent. On April 1, 2003, Universal filed its answer and counterclaims also denying Honeywell’s allegations and seeking a declaratory judgment of invalidity and noninfringement. On April 14 and April 21, 2003, Honeywell. filed its answers to Sandel’s and Universal’s respective counterclaims. On July 26, 2004, Universal filed a Motion for Summary Judgment of Non-Infringement. On August 2, 2004, Sandel also filed a Motion for Summary Judgment of Non-Infringement. The parties submitted a Joint Submission of Claim Construction of. U.S. Patent No. 4,914,436 on June 29, 2004. The parties submitted briefing on defendants’ motions for summary judgment of non-infringement which include the parties’ respective proposed definitions of the disputed claim terms relevant to those motions.. Pursuant to Markman v. Westview Instruments, Inc. and local practice, oral argument was held on November 9, 2005 on the parties’ proposed claim constructions and motions for summary judgment. This opinion sets forth the court’s construction of the disputed claim terms and the court’s determination with regard to defendants’ motions for summary judgment. II. BACKGROUND A. The Patented Invention The ’436 patent, entitled “Ground Proximity Approach Warning System Without Landing Flap Input,” which, as described by Honeywell, discloses and claims: A system that determines whether and what modes of a ground proximity warning system should be in effect when an aircraft comes within a specified distance of an airport for landing.... The system does so by determining the aircraft’s distance from an airport and its alignment with a runway, and enables a warning system as a function of the distance of the aircraft from the airport. Claims 1, 2, 4, and 5 of the ’436 patent are at issue. Claim 1 reads as follows (with the disputed claim terms in bold): 1. A system for use in an aircraft for providing an enabling envelope for a ground proximity warning system for an aircraft comprising: a first source of signals representative of the longitude and latitude of an airport; a second source of signals representative of the current longitude and latitude of said aircraft; means responsive to said first source of signals representative of the longitude and latitude of said airport and said second source of signals representative of the current longitude and latitude of said aircraft for computing the distance of said aircraft from said airport and providing an enabling envelope for enabling the warning system as a function of said distance of the aircraft with respect to said airport; a source of signals representative of the relative angular position of a particular runway with respect to the heading of the aircraft; and means responsive to said first and second sources of signals for providing a signal representative of the alignment of the aircraft with the runway by determining the angle between the runway and the heading of the aircraft. Claim 2 of the ’436 patent reads as follows (with the disputed claim terms in bold): 2. A warning system for use in an aircraft comprising: warning means for providing a ground proximity warning according to predetermined criteria; a first source of signals representative of the longitude and latitude of an aircraft; a second source of signals representative of the longitude and latitude of a predetermined geometric shape; means responsive to said first source of signals and said second source of signals for computing the distance between the aircraft and said predetermined geometric shape and for enabling the warning means as a function of the difference; a third source of signals representative of the relative angular position of a particular runway with respect to the heading of the aircraft; and means responsive to said first, second and third sources of signals for providing a signal representative of the alignment of the aircraft with the runway. Claim 4 of the ’436 patent reads as follows (with the disputed claim terms in bold): 4. A system for an aircraft comprising: warning means for providing a ground proximity warning when an aircraft encounters a hazardous flight condition; enabling means for enabling said warning means according to predetermined criteria; a first source of signals representative of the relative angular position of a predetermined runway at an airport nearest the aircraft with respect to the heading of the aircraft; a second source of signals representative of the longitude and latitude of the aircraft; a third source of signals representative of the longitude and latitude of the airport nearest the aircraft; and determining means responsive to said first source of signals, said second source of signals and said third source of signals for determining the aircraft’s alignment with respect to said predetermined runway and altering said criteria for said enabling means as a function of the alignment of the aircraft with respect to said predetermined runway. Claim 5 of the ’436 patent reads as follows (with the disputed claim terms in bold): 5. A system for an aircraft comprising: a first source of signals representative of the longitude and latitude of an aircraft; a second source of signals representative of the predetermined airport as modeled by a predetermined geometric shape; a third source of signals representative of the relative angular position of a predetermined runway at said predetermined airport with respect to the heading of the aircraft; means responsive to said first source of signals, said second source of signals, and said third source of signals for providing a distance signal representative of the distance between the aircraft and the nearest airport as modeled by said predetermined geometric shape and the alignment of the aircraft with said predetermined runway; warning means for providing a warning when an aircraft encounters a hazardous flight condition; enabling means responsive to said distance signal providing means for generating an enabling signal for enabling said warning means at a predetermined distance from said airport; first altering means for altering said enabling signal as a function of the distance of the aircraft from said nearest airport; a third source of signals representative of the heading of a predetermined runway at said nearest airport; and second altering means for altering said enabling signal as a function of the alignment of the aircraft with said runway. The parties have stipulated that the meaning of the of the following terms and phrases of the asserted claims are disputed: 1. “ground proximity warning system”; “warning system” 2. “heading” 3. “alignment” 4. “enabling” 5. “enabling envelope” The court will construe each of these claim terms in turn. III. THE LAW OF PATENT CLAIM CONSTRUCTION “A patent infringement analysis involves two steps: claim construction and application of the properly construed claim to the accused product.” The patent claims define the scope of the rights afforded. to the patentee under the patent, and the interpretation and construction of those claims is a matter of law to be determined by the court. When construing the claims, the court may consider “both intrinsic evidence (e.g., the patent specification and file history) and extrinsic evidence (e.g., expert testimony).” The court must first examine “the intrinsic evidence of the- record, ie.,-the patent itself, including the claims, the specification and, if in evidence, the prosecution history.” The starting point for the court’s examination is the language of the disputed claim.' In construing claims, the analytical focus must begin and remain centered on the language of the claims themselves .... The terms used in the claims bear a ‘heavy presumption’ that they mean what they say and have the ordinary meaning that would be attributed to those words by persons skilled in the relevant art.... [UJnless compelled otherwise, a court will give a claim term the full range of its ordinary meaning as understood by persons skilled in the relevant art.... Dictionaries, encyclopedias and treatises, publicly available at the time the patent is issued, are objective resources that serve as reliable sources of information on the established meanings that would have been attributed to the terms of the claims by those of skill in the art.... As resources and references to inform and aid courts and judges in the understanding of technology and terminology, it is entirely proper for both trial and appellate judges to consult these materials at any stage of a litigation, regardless of whether they have been offered by a party in evidence or not. Thus, categorizing them as ‘extrinsic evidence’ or even a ‘special form of extrinsic evidence’ is misplaced and does not inform the analysis.” After consulting relevant dictionaries to determine the ordinary meaning of disputed terms, the intrinsic record must always be analyzed “to determine whether the presumption of ordinary and customary meaning is rebutted ... [such as when] the specification uses the words in a manner clearly inconsistent with the ordinary meaning reflected, for example, in a dictionary definition. In such a case, the inconsistent dictionary definition must be rejected.” Only if there is still ambiguity as to the meaning of a claim after reviewing the intrinsic evidence should a court consider extrinsic evidence, such as expert or inventor testimony. If the court does find it necessary to consider extrinsic evidence, however, that evidence may never be used “for the purpose of varying or contradicting the terms in the claims.” IV. THE COURT’S CLAIM CONSTRUCTION A. Ground Proximity Warning System; Warning System 1. Parties’Positions Although listed as separately-disputed claim terms, the parties propose similar constructions for “ground proximity warning system” and “warning system.” Honeywell argues that the specification supports a construction of these terms as “a system that serves to monitor the flight conditions of an aircraft and provide a warning if flight conditions are such that an inadvertent contact with the ground is imminent.” Defendants argue that these terms “should be construed as reciting the prior art ground proximity warning system (GPWS) modes” referenced in the ’436 patent. They argue that, at least as to Claim 1, the warning system is recited in a means-plus-function format and, therefore, that claim is limited to the warning modes described in the specification. Defendants argue further that the understanding of one skilled in the art, the specification, and the prosecution history support their proposed construction. 2. Court’s Construction The parties argue for a common construction for each of the terms “ground proximity warning system” and “warning system.” The dispute regarding the warning system limitations centers on whether or not the those limitations cover only the particular prior art ground proximity warning systems recited in the ’436 patent. Each party points to the ’436 patent specification as supporting their respective constructions. Defendants’ first argument is based upon their assertion that the warning system limitations of claim 1 are written in a means-plus-function format. Claims written in a means-plus-function format are limited to those structures recited in the specification and their equivalents. Defendants contend that “the warning system of Limitation 3 [of claim 1] is described in mean-plus-function format. It is therefore limited to the precise GPWS modes disclosed in the specification, ie., Mode 2 (Terrain Closure) and Mode 4 (Terrain Clearance).” The relevant language of claim 1 is as follows: 1. A system for use in an aircraft for providing an enabling envelope for a ground proximity warning system for an aircraft comprising: ^ 5¡: ‡ ‘A- means responsive to said first source of signals representative of the longitude and latitude of said airport and said second source of signals representative of the current longitude and latitude of said aircraft for computing the distance of said aircraft from said airport and providing an enabling envelope for enabling the warning system as a function of said distance of the aircraft with respect to said airport; .... The language “means ... for computing the distance of said aircraft from said airport and providing an enabling envelope for enabling the warning system as a function of said distance of the aircraft with respect to said airport” is not written in a means-plus-function format with respect to the term “warning system.” In that limitation, “the warning system” refers back to “a ground proximity warning system” recited in the preamble to claim 1. The means-plus-function format is directed at a “means ... for ... computing the distance of said aircraft from said airport and providing an enabling envelope ....” Because “the warning system” recited in claim 1 is not written in a means-plus-function format, defendants must point to language in the specification or prosecution history to support their proposed construction. The ’436 patent recites that the invention described therein “generally relates to a system for enabling an aircraft ground proximity warning system ....” Describing the prior art, the specification states that: Various systems are known that provide warning or advisory indications in the event of hazardous flight conditions. Among such systems are systems generally known as ground proximity warning systems for aircraft that serve to monitor the flight conditions of an aircraft and provide a warning if flight conditions are such that an inadvertent contact with the ground is imminent. The specification continues with a recitation of examples of prior art warning systems. The parties each cite this language in support of their respective positions. Defendants argue that that language demonstrates that the invention is limited to the referenced prior art GPWS. Honeywell argues that the above-quoted language does not limit the invention to the prior art, but merely defines “ground proximity warning systems” as systems “that serve to monitor the flight conditions of an aircraft and provide a warning if flight conditions are such that an inadvertent contact with the ground is imminent.” Contrary to defendants’ position, the patent clearly states that the prior art warning systems recited in the specification are merely examples of such systems. Thus, even if defendants are correct that those of ordinary skill in the art at the time of the invention would have understood the warning system limitations to refer to the prior art GPWS, the court determines that ’436 patent’s definition of the warning systems, recited above, controls the construction of that phrase. Furthermore, and also in contradiction of defendants’ position that the specification limits the invention “to the two warning modes described in the specification, i.e., Mode 2 ... and Mode 4,” the ’436 patent repeatedly disclaims limitation to particular warning systems. The specification states that, “[an] object of the present invention [is] to provide a warning system that overcomes many of the disadvantages of the prior art systems.” “[A]nother object of the invention is to provide an enabling envelope for enabling various warning systems ....” The preferred embodiment of the ’436 patent discloses a system “for generating an enabling envelope for enabling various warning systems when an aircraft is on final approach to an airport.” The specification goes on to recite that “various ground proximity warning systems, such as, Mode 2 and Mode 4 warning systems, can be enabled.” Defendants argue that: [although Honeywell asserts that a reference to “additional modes” in the specification requires a broader construction that includes the enabling of warning systems other than GPWS, there is no support for that contention in the patent or the file history. The specific passage Honeywell relies upon refers to “other modes” (i.e. GPWS modes 1, 3 and 5) and not other types of warning systems. As noted above, the specification recites that the invention enables “various warning systems.” While figure 3 of the ’436 patent is described as “illustrating] an enabling envelope for a Mode 2 (Terrain Closure) warning system,” the specification states that “[t]he Mode 2 warning envelope is shown as an example only. The system in accordance with the present invention may also be used to enable other warning modes and even used in control systems.” There is nothing in the ’436 patents’ claim language that indicates a limitation to particular prior art GPWS modes. The specification provides a general definition of warning systems as those systems “that serve to monitor the flight conditions of an aircraft and provide a warning if flight conditions are such that the inadvertent contact with the ground is imminent.” An object of the invention is “to provide an enabling envelope for enabling various warning systems ....” The unambiguous language of the specification, therefore, supports Honeywell’s argument that the patentees did not limit their invention to particular prior art warning systems or modes. Moreover, defendants’ argument that the ’436 patent should be construed as limited “to the two warning modes described in the specification” would require the court to limit the patent to the preferred embodiment described therein. Contrary to defendants’ position, the specification states that signals generated by the invention “may be used with various ground proximity warning systems ....” Although the specification describes “input to a Mode 2 ... and a Mode 4 ... warning system,” the very next sentence reiterates that “the invention is not limited to such use. The system ... can be used in virtually any warning or control system where such a signal is required.” Reading a preferred embodiment limitation into the claims, here Mode 2 and Mode 4 warning systems, is generally improper and would certainly be so here in light of the plain language of the specification. Defendants also refer the court to the prosecution history as supporting their proposed construction of the warning system limitations. Defendants contend that the patentee narrowed the scope of the invention to prior art GPWS and that Honeywell can not now argue that the ’436 patent covers art previously disclaimed during prosecution. Each defendant, however, cites different portions of the prosecution history to support this argument. Universal argues that as a consequence of the ’436 patent applicants’ amendment of application claim 12 to include the words “ground proximity” before existing the application limitation of “a warning system” recited in that claim, “Honeywell should be estopped from asserting that the ground proximity warning system could be construed generieally to cover other types of warning systems.” As originally filed, application claim 12 read, in the relevant part, A system for use in an aircraft for providing an enabling envelope for a warning system comprising: * * * :\i * * means ... for providing an enabling envelope for enabling a warning system as a function of the relative position of the aircraft with respect to the reference point. In the first Office Action, the examiner rejected application claim 12 under 35 U.S.C. § 112, second paragraph, because “it is unclear what a warning system is used for.” The applicants amended the claim to recite: A system for use in an aircraft for providing an enabling envelope for a ground proximity warning system for an aircraft comprising: ^4 íjí ^5 means ... for computing the distance of said aircraft from said reference point and providing an enabling envelope for enabling [a] the warning system as a function of the said distance [relative position] of the aircraft with respect to [the] said reference point.” The examiner’s rejection did not require, or suggest, that the applicants specify a particular warning system, and the amendment indicated no such limitation. The amendment answered the examiner’s question as to what the warning system was used for by reciting that it was a “ground proximity warning system for an aircraft.” Consequently, the court rejects Universal’s argument that the prosecution history limits the ’436 patent to covering only prior art GPWS. Sandel points to a different portion of the prosecution history to support its argument that the warning system limitations should be limited to those prior art GPWS described in the specification. Sandel notes that in a February 25, 1988 Office Action, the examiner rejected twenty of the application’s twenty-six claims as obvious over Bateman in view of a 1987 Parnau article entitled “IFR Flight with the New Lorans.” Sandel contends that the applicants’ amendment in response to that rejection supports its proposed construction of the warning system limitations. The examiner stated that “Parnau discloses that a Loran, which utilizes latitude/longitude coordinates, can give a warning when an aircraft nears restricted airspace ... based on how far the aircraft is from the [restricted airspace].” The Parnau system, combined with the invention described in the Bateman patent, led the examiner to reject most of the application claims as obvious. In an August 29, 1988 Amendment, the applicants responded to the examiner’s obviousness rejection by arguing that: [t]he warning system discussed in the Parnau article relates to a LORAN SYSTEM having a restrictive air space warning .... Such a warning is a geographical warning and is based solely on longitude and latitude coordinates. However, it does not suggest in any way how a LORAN system could be used to vary a ground proximity warning system .... [The system described in the Parnau article] can only provide longitude and latitude coordinates. There is no suggestion in the Parnau article how such information would be used to vary a warning envelope or enable a warning envelope other than a geographic warning such as a ground proximity warning system as recited in the claims at issue. In a December 6, 1988 Office Action, the examiner again rejected seventeen of the application claims, this time, as obvious over Nolan in view of Parnau. The examiner stated that “Parnau teaches that it is known in the art to give a warning when an aircraft is within a predetermined distance to a TCA or restricted area.” In a March 20, 1989 Amendment, the patent applicants again distinguished Parnau, responding that: the Parnau reference relies on distance as an operative warning parameter. Specifically, Parnau discloses .. a restricted airspace warning which generates a warning when an aircraft enters a restricted airspace. However, such a warning is based solely on the distance of the aircraft from the restricted airspace. In contradistinction, the warning system recited in the claims at issue recites “a warning of a hazardous flight condition” enabled “as a function of the distance between the aircraft and a reference point.[”] Thus, it should be clear that contrary to the teachings of Parnau, the warning system recited in the claims at issue does not utilize distance as an operative warning parameter, but merely to enable the warning system. No such warning of a hazardous flight condition is taught or implied in Parnau. In a June 5, 1989 Office Action, the examiner withdrew the objections and rejections made in the December 6, 1988 Office Action in view of the applicants’ March 20, 1989 Amendment and did not renew any obviousness rejection based on the Parnau article. Sandel argues that “Honeywell distinguished] Parnau by amending the claims specifically to recite ‘ground proximity warning system.... ’ Thus, to overcome a prior art rejection, Honeywell narrowed the scope of the claimed invention by specifically using words applied to an existing, well-known technology.” Initially, the court notes that Sandel’s argument presumes that “ground proximity warning system” is limited to the prior art GPWS. As explained above, the court determines that the specification rebuts that presumption. Secondly, the prosecution history does not support Sandel’s contention that the applicants added the words “ground proximity” before “warning system” in some of the claims rejected as obvious in order to distinguish Parnau. In the August 29, 1988 Amendment, the words “ground proximity” were added before “warning system” in application claims 1,12, 15 and 21. Application claims 1, 12, and 15 were not subject to the Parnau-based obviousness rejection recited in the February 25, 1988 Office Action. Therefore, the addition of the words “ground proximity” to those claims was not made to distinguish Parnau. Moreover, the applicants’ narrative explanation of the amendments to application claims 1, 12, and 15 demonstrate that addition of the words “ground proximity” was not even made to address the particular bases of the examiner’s rejection of those claims. Application claim 21 was the only claim of the twenty application claims rejected as obvious, in part, with reference to the Parnau article amended to include the words “ground proximity.” The applicants’ narrative explanation of the amendment to application claim 21 is not directed to the examiner’s Parnau-based obviousness rejection but, rather, to the examiner’s rejection of that claim because “‘it [was] unclear how an alignment with the runway is sensed or why criteria is altered’.” In response to that rejection, the applicants amended application claim 21 to recite: A system for an aircraft comprising: warning means for providing a ground proximity warning when an aircraft encounters a hazardous flight condition * * * * * * determining means responsive to said first source of signals and said second source of signals for determining the aircraft’s alignment with respect to said predetermined runway and altering said criteria for said enabling means as a function of the alignment of the aircraft with respect to said predetermined runway. The section of the August 29, 1988 Amendment in which the applicants distinguished Parnau made no reference to particular prior art GPWS systems. Instead, the applicants argued that the system described in Parnau “relates to a LORAN SYSTEM having a restrictive air space warning .... Such a warning is a geographical warning and is based solely on longitude and latitude coordinates. However, it does not suggest in any way how a LORAN system could be used to vary a ground proximity warning system.” That the addition of the words “ground proximity” in application claim 21 was not included by applicants to distinguish the Parnau article is also confirmed by subsequent prosecution history. Amended application claim 21, and others, were again rejected by the examiner, this time in a December 6, 1988 Office Action “as being unpatentable over Nolan in view of Par-nau.” Obviously, Sandel’s alleged limitation to prior art GPWS was not sufficient in the examiner’s opinion to distinguish Parnau. Again, in response to the December 6, 1988 Office Action, the applicants did not distinguish Parnau with any reference to prior art GPWS. The applicants argued that: the Parnau reference relies on distance as an operative warning parameter .... [The system described in Parnau generates] a warning ... based solely on the distance of the aircraft from the restricted airspace.... [T]he warning system recited in the claims at issue does not utilize distance as an operative warning parameter, but merely to enable the warning system. Because the applicants never distinguished their .invention from Parnau with reference to the prior art GPWS, the court will not construe the asserted claims as so limited by the prosecution history. Consequently, the court determines that “ground proximity warning system” and “warning system” are construed according to the definition set forth in the ’436 patent to mean “a system to monitor the flight conditions of an aircraft and provide a warning if flight conditions are such that an inadvertent contact with the ground is imminent.” B. Heading 1. Parties’Positions Universal and Sandel each propose that the term “heading” be given its ordinary and accustomed meaning, “the direction in which the aircraft is pointing in relation to magnetic or true North.” Defendants cite both general-usage and technical dictionaries to provide this definition of “heading.” Honeywell does not dispute defendants’ suggested ordinary meaning of the term “heading.” Instead, Honeywell contends that the patent specification and prosecution history demonstrate that the patentee acted as his own lexicographer and created a special meaning for the term “heading.” Honeywell argues that the patentee defined “heading” as having the ordinary meaning of the term “bearing”; “the angle formed by the line connecting the aircraft position and the airport and a reference datum, usually North.” Defendants do not dispute the definition of “bearing” proffered by Honeywell, however, they argue there is nothing in the intrinsic record which compels ascribing anything other than the ordinary meaning of “heading” to that term. 2. Court’s Construction The dispute with regard to the term “heading” is whether that term should be construed to have its ordinary meaning or whether “heading” should be defined to have a special meaning; the same meaning as the term “bearing.” The parties agree that the ordinary meaning of the term “heading” is “the direction in which the aircraft is pointing in relation to magnetic or true North.” There is a “heavy presumption” that claim terms “mean what they say and have the ordinary meaning that would be attributed to those words by persons skilled in the relevant art.” This presumption can be overcome when “a paten-tee ... ehoose[s] to be his own lexicographer and use[s] the terms in a manner other than their ordinary meaning, as long as the special definition of the term is clearly stated in the patent specification or file history.” A special definition may be clearly stated by the patentee without being explicitly stated and that special definition may be set forth in either the specification or in the prosecution history. Here, Honeywell argues that the specification gives a special meaning of the term “heading” which is uncontradicted by the prosecution history. Each of the asserted claims contain the phrase “signals representative of the relative angular position of a ... runway ... with respect to the heading of the aircraft.” Although the word “heading” is not recited in the specification, Honeywell contends that the description of the alignment function recited in the claims demonstrates that the term “heading” was redefined to have the ordinary meaning of the term “bearing.” The ’436 patent describes as an “important feature” of the invention “a system ... for determining the alignment of the aircraft with a particular runway .... This feature is illustrated in Fig. 5.” Figure 5 is reproduced below for reference. Honeywell argues that “[t]he structure that performs the ‘alignment’ function of the ’436 Patent includes Col. 6, lines 6-36 and Fig. 5, items 46-58.” To determine this alignment, the invention calculates and compares angles that reference the aircraft and a particular runway. . The alignment function of the ’436 patent is described in the specification as follows: The signals X, Y, which are longitudinal and latitudinal components, respectively represent the distance of the aircraft from the airport. The signals X and Y are applied to a divider 46 (FIG.5). The signals X and Y are obtained from the outputs of the summing junctions 18 and 20 (FIG.4). The output quotient signal from the divider 46 is, in turn, applied to an absolute value device 47. The absolute value device 47 generates an output signal which is always positive. The output of the absolute value device 47 is applied to an arctan device 48, which provides a signal which is representative of the angle between a line segment connecting the present aircraft position and the centerpoint coordinates of the nearest airport and a reference datum. The output from the arctan device 48 is applied to a positive input of a summing junction 50. A signal, which represents the angle that the runway of interest makes with a datum, is applied over line 53 to a negative input of the summing-junction 50. The output of the summing junction 50 is a signal representing the angular difference between the present relative position of the aircraft and the runway. In other words, the summing junction 50 provides a signal which is representative of the aircraft’s alignment with the particular runway. To summarize, “an arctan device 48, ... provides a signal which is representative of the angle between a line segment connecting the present aircraft position and the centerpoint coordinates of the nearest airport and a reference datum.” Another signal is generated “which represents the angle that the runway of interest makes with a datum ....” Finally, the system compares these two angles and “provides a signal which is representative of the aircraft’s alignment with the particular runway.” The signal generated with respect to the aircraft is described as “representative of the angle between a line segment connecting the present aircraft position and the centerpoint coordinates of the nearest airport and a reference datum.” This is synonymous with Honeywell’s proffered definition of “bearing”; “the angle formed by the line connecting the aircraft position and the airport and a reference datum.” Nowhere does the specification recite the generation of a signal with respect to the aircraft that meets the ordinary definition or “heading,” “the direction in which the aircraft is pointing in relation to magnetic or true North.” At oral argument, Sandel conceded that “the angle between a line segment connecting the present aircraft position and the centerpoint coordinates of the nearest airport and a reference datum” describes the bearing of the aircraft. Sandel argues, however, that the patent does not claim that language and does not contain a claim covering figure 5 of the ’436 patent. This is a surprising argument for two reasons. First, Sandel cites figure 5 and the specification’s description of the invention’s alignment function in support of its proposed construction of the term “alignment.” Second, figure 5 is described as “a functional block diagram of a system for determining the alignment of the aircraft with respect to a particular runway in accordance with the patented invention.” The alignment feature that Sandel argues is not claimed by the ’436 patent is described as part of the preferred embodiment of the claimed invention. During prosecution, the examiner’s attention was also brought to figure 5, clearly indicating that figure 5 was being claimed. To restrict the claim term “heading” to its ordinary meaning would exclude a preferred embodiment recited in the patent since it is agreed by the parties that the above-quoted language clearly describes an embodiment wherein the bearing of an aircraft is calculated. Just as it is improper to read a limitation from a preferred embodiment into the claims, the Federal Circuit has cautioned that to construe a term to exclude a preferred embodiment “is rarely, if ever, correct.” The court concludes, therefore, that the specification is clear in its implicit definition of “heading” to have the ordinary meaning of “bearing.” The prosecution history also supports this conclusion. In a December 6, 1988 Office Action, the examiner rejected application claim 21 and objected to application claim 24, among others, stating that: [i]n claim 21 determining means are said to find aircraft alignment with respect to a runway based on runway heading and latitude and longitude data. However, it appears that in order to operate the means would also have to receive inputs from an aircraft heading device. In claim 24 is [sic] appears that aircraft alignment could not be found without aircraft heading inputs. Language as used in amended claims 14 and 19 is suggested to rectify this problem. In a March 20, 1989 Amendment, the applicants resisted the examiner’s suggested amendment to application claims 21 and 24 arguing that: [a]s illustrated and described in the specification, the invention as claimed utilizes the latitude and longitude coordinates of the aircraft with respect to the nearest airport to determine the heading of the aircraft with respect to the runway. The Examiner’s attention is respectfully direct to FIG. 5 and page 10 of the specification, line 25 et seq. The alignment of the aircraft with respect to the runway is determined by utilizing line segments X and Y generated by the local airport search routine 16. The line segments X and Y represent the difference between the current aircraft latitude and longitude and the latitude and longitude of the nearest airport respectively. These line segments Y and X are fed into a dividing circuit 46 to generate a quotient signal Y/X. After being applied to an absolute value circuit 47, this signal is applied to the arctan device 48 to determine the angular relationship between the aircraft heading and the airport. Thus, the output signal from the arctan device 48 represents the heading of the aircraft. The heading of the aircraft is compared with the heading of the runway course in a summing device 50 to determine the alignment of the aircraft with respect to a particular runway. Thus, it should be clear that the “determining means” does not require the use of a separate heading sensing device for the aircraft. The heading of the aircraft is determined by the circuitry which includes the function blocks 46, 47 and 48. Accordingly, it is respectfully requested that the rejection of claim 21 be reconsidered and withdrawn. In a June 5, 1989 Office Action, the examiner again rejected application claims 21 and 24, reiterating that “[i]n claims 21 and 24 the use of aircraft alignment with a runway is described, but it appears that in order to be operational, aircraft heading inputs would have been necessary, and no such inputs are claimed.” In an October 30, 1989 Amendment, the applicants acquiesced to the examiner’s previous suggestion and amended application claims 21 and 24 to include the limitation “with respect to the heading of the aircraft.” With that amendment, the examiner allowed the claims on November 3, 1989. Significant to the construction of the term “heading” is the applicants’ statement to the examiner that “the output signal from the arctan device 48 represents the heading of the aircraft.” This output signal was described in the application specification, to which the examiner was referred, as “a signal which is representative of the angle between a line segment connecting the present aircraft position and the centerpoint coordinates of the nearest airport and a reference datum.” Defendants argue that the above-quoted prosecution history does not support Honeywell’s construction. Defendants argue that the prosecution history demonstrates that “the Examiner repeatedly rejected application claims for failure to specify a source of heading signals — but not because the commonly understood term required definition.” According to defendants it is clear that “that the examiner’s concern was not over what ‘heading of the aircraft’ meant, but that this ‘heading’ was not explicitly recited in the claims he objected to... [and that] the examiner did not agree with Honeywell’s arguments or read them to ‘redefine’ the meaning of heading.” Defendants’ argument is unavailing. As defendants correctly point out, “the claims [the examiner] was objecting to defined the runway direction portion of the claim, but failed to recite the necessary aircraft heading.” A similar objection was previously made by the examiner and remedied by the applicants with respect to application claims 14 and 19. As originally filed, application claim 14 recited “[a] system ... including a source of signals representative of the relative angular position of a particular runway with respect to a datum.” The examiner rejected these claims under 35 U.S.C. § 112, second paragraph, as being indefinite. The examiner stated that “[i]n claim 14 it is unclear how a runway is compared to a datum or how alignment with a runway is sensed.” The applicants amended those claims by deleting the reference to “a datum” and adding “with respect to the heading of the aircraft.” After failing to convince the examiner that the same limitation was not required in application claims 21 and 24, the applicants amended those to include that limitation. The prosecution history demonstrates that defendants’ argument that “the examiner did not ... read [Honeywell’s arguments] to ‘redefine’ the meaning of heading” misses the point. Indeed, defendants are correct that “the examiner’s concern was not over what ‘heading of the aircraft’ meant, but that this ‘heading’ was not explicitly recited in the claims he objected to.” The applicants did not attempt to avoid the examiner’s rejection of application claims 21 and 24 by redefining the meaning of “heading” or arguing that the examiner did not understand the meaning of that term. Rather, the applicants argued that “the ‘determining means’ [did] not require the use of a separate heading sensing device for the aircraft.” Nothing concerning the examiner’s rejections or the applicants’ responsive amendments suggests that the application failed to define “heading.” That fact negates defendants’ assertion that “[i]f Honeywell’s engineers truly meant to define the claims in terms of bearing, rather than attempting to use an ambiguous and counter-intuitive ‘special use’ of the term ‘heading’, they would have simply amended (or originally written) the claims to read ‘bearing’ instead of ‘heading.’ ” As defendants acknowledge, it was not the definition of heading (or bearing) that concerned the examiner, it was the absence of the limitation reciting heading (or bearing) signals that lead to the examiner’s rejection. Once that limitation was added, the examiner allowed the ’436 patent to issue. Whether or not the examiner knew the ordinary meaning of “heading” is immaterial since a patent applicant may redefine its claim terms to have a definition other than the ordinary meaning of that term. It is clear from both the specification and the prosecution history that the “heading” of the aircraft is represented by “a signal which is representative of the angle between a line segment connecting the present aircraft position and the cen-terpoint coordinates of the nearest airport and a reference datum.” That representation of “heading” is the same as the ordinary meaning of the term “bearing.” Consequently, defendants’ argument that “heading” should be construed according to the ordinary meaning of that term is rejected. The court determines that “heading” was redefined by the applicants to mean “the angle formed by the line connecting the aircraft position and the airport and a reference datum.” C. Alignment 1. Parties’ Positions Honeywell argues that “ ‘[alignment’ is the arrangement, or position, of parts of an object or system in correct relationship to each other.” Sandel argues that “ ‘[alignment’ should be afforded its plain and ordinary meaning of ‘lined up with’ or ‘in line with’ ” Universal offered no proposed definition for the this claim term in the parties’ Joint Submission of Claim Construction. 2. Court’s Construction None of the parties has cited a reference to the court for their proposed meanings of “alignment,” however, the proposed constructions are consistent with the ordinary meaning of those terms as reflected in common usage dictionaries available at the time of the invention. One meaning of “alignment” is “1. Arrangement or position in a straight line. 2. [t]he process of adjusting a device or mechanism or the condition of a device or mechanism being adjusted.” Those definitions are consistent with other general use dictionary definitions of “alignment” and “align.” There is no dispute over the structures described in the specification that perform the alignment function and the ordinary meaning of that term is consistent with that description. Since the parties’ proposed constructions of “alignment” is consistent with the ordinary meanings of that term, the court determines that the broadest appropriate definition of “alignment” that is consistent with the structures that perform the alignment function described in the specification is “the process of adjusting to produce a proper condition or relationship.” D. Enabling 1. Parties’ Positions Although the parties include “enabling” on the Joint Submission of Claim Construction, there is no difference in the parties’ proposed definitions in that submission. Each party contends that the term “enable” means “to activate or turn on.” At oral argument, the parties were in substantial agreement with this definition. Honeywell agreed with that definition of “enable.” Defendants first stated that “enable” means “to activate or turn on as distinguished from issuing an alert” Later Universal directed the court to the parties’ Joint Submission of Claim Construction stating that each party defined “enabling [as] ‘mean[ing] activating or turning on’. So it would seem that the record presently before the Court reflects a unanimous ... position with respect to all three parties concerning the definition of the word enabling.” Based on this assertion, and Honeywell’s agreement that “[enable] should be construed the way the parties agreed and submitted it to [the court] as a claim construction,” the court will construe “enabling” according to that submission to mean “activating or turning on.” 2. Court’s Construction While neither party cites relevant dictionaries in support of its position, the court notes that the proposed definitions by the parties is consistent with the definitions of enable recited in common-use dictionaries. No party pointed to any intrinsic evidence, and the court has found none, that would lead to a contrary construction of “enable.” Consequently, the court determines that “enabling” means “activating or turning on.” E. Enabling envelope 1. Parties’Positions The parties did not propose specific constructions of the term “enabling envelope” in their Joint Submission of Claim Construction but informed the court at oral argument that this is a term that requires the court’s construction. At oral argument, Universal argued that “enabling envelope” should be not defined as “limited to any envelope which activates or turns on” but should exclude any envelope which is, in part, enabled by the use of flap position input. Honeywell contends that such a construction would improperly read a negative limitation into the asserted claims. Sandel argues that an enabling envelope cannot be construed to include a system that suppresses alerts, as its VAP allegedly does. 2. Court’s Construction At oral argument, the parties did not contend that “enabling envelope” is a term of art having a specific definition. The court has construed “enabling” to mean “activating or turning on.” Therefore, the claim term “enabling envelope” must mean turning on or activating an “envelope.” None of the parties specifically addressed the definition of the word “envelope.” One relevant definition of “envelope” found by the court is “[t]he set of limitations within which a technological system, especially an aircraft, can perform safely and effectively.” This definition is consistent with the ’436 patent’s description of “enabling envelope.” The specification describes “provid[ing] an enabling envelope for enabling various warning systems . In describing the “generation [of] an enabling envelope for enabling various warning systems” the specification recites that “individual airports, together with contiguous terrain topography, are modeled by a simple geometric shape, such as, a truncated inverted cone ....” “Whenever the aircraft is within the boundaries of the envelope, various ground proximity warning systems ... can be enabled.” As defined by the specification, and construed by the court, the “warning system” enabled by the warning envelope is “a system to monitor the flight conditions of an aircraft and provide a warning if flight conditions are such that an inadvertent contact with the ground is imminent.” These warning systems “provide an advisory warning in the event of a hazardous flight condition.” The envelope described in the specification, therefore, is “the set of limitations within which ... an aircraft can perform safely and effectively.” That set of limitations corresponds to a determined volume of airspace which is “modeled by a simple geometric space.” Thus, when an aircraft is within the envelope, the invention can enable (activate or turn on) various warning systems which will alert the pilot of a hazardous flight condition, ie., when the aircraft is not flying safely and effectively. Although the specification’s statement that “[t]he system in accordance with the present invention avoids [the] problem [encountered by prior GPWS] because it does not rely on flap or landing gear position signals,” might appear to support Universal’s argument that the ’436 patent does not cover an enabling envelope which does use flap or landing gear position, the claims, specification, and prosecution history support Honeywell’s argument that that “negative limitation” is not included in the claimed invention. The specification recites three objects of the invention: [1] to provide a means for detecting whether an aircraft is on a final approach to an airport without the use of a flap position signal.... [2] to provide a means for detecting the proximity of an aircraft to a particular airport without utilizing a substantial amount of memory on board the aircraft [ie., determining the distance of the aircraft from a particular airport].... [3] to provide an enabling envelope for enabling various warning systems based on the position of the aircraft relative to the airport. Turning first to the claims, the third limitation of claim 1, upon which the parties focused their arguments, states: means responsive to first source of signals representative of the longitude and latitude of said airport and said second source of signals representative of the current longitude and latitude of said aircraft for computing the distance of said aircraft from said airport and providing an enabling envelope for enabling the warning system as a function of said distance of the aircraft with respect to said airport. The functions of this means-plus-function limitation are: (1) determining the distance of the aircraft from a particular airport and (2) providing an enabling envelope for enabling the warning system. Determination of whether the aircraft is on final approach is not a function claimed in the above-quoted limitation and it would be improper for the court to import that additional limitation. Furthermore, there is no mention of the absence of flap or gear position inputs in any of the ’436 patent’s claims. Turning to the specification, each of the several references to flap and gear position therein refer to a determination of whether an aircraft is on final approach. None of the ’436 patents’ claims, however, includes any reference to a determination of whether an aircraft is on final approach. Examination of the prosecution history reveals that, originally, the patent application included such a claim. Application claim 3 recited: “[a] system for use in an aircraft comprising: ... means responsive to said determining means for providing a signal representing that the aircraft is on said final approach.” In a February 25, 1988 Office Action, the examiner rejected application claim 3 under 35 U.S.C. § 112, first paragraph, for “not adequately describing] how a final approach would be sensed.” In an August 29,1988 Amendment, the applicants cancelled application claim 3, as well as application claims 4 and 5 which depended therefrom and had also been subject to the examiner’s February 25, 1988 rejection. The application specification was not amended to remove the references to a determination of when an aircraft is on final approach. Because the specification refers to the absence of flap and gear position inputs only in connection with a determination of whether an aircraft is on final approach and because none of the ’436 patent’s claims recite any flap and gear position limitation, or determination of final approach limitation, the court rejects Universal’s argument that “enabling envelope” should be construed so as not to include systems which include flap and gear position inputs. Consequently, the court construes “enabling envelope” to mean “activating or turning on a set of limitations within which an aircraft can perform safely and effectively.” Y. CONSTRUCTION OF DISPUTED CLAIM TERMS The court construes the disputed claim terms as follows: Claim Language Court’s Construction “ground proximity warning system”; “warning system” a system to monitor the flight conditions of an aircraft and provide a warning if flight conditions ai’e such that an inadvertent contact with the ground is imminent “heading” the angle formed by the line connecting the aircraft position and the airport and a reference datum “alignment” the process of adjusting to produce a proper condition or relationship “enabling” activating or turning on “enabling envelope” activating or turning on a set of limitations within which an aircraft can perform safely and effectively VI. PARTIES’ SUMMARY JUDGMENT ARGUMENTS Honeywell alleges that defendants’ products infringe the ’436 patent either literally or under the doctrine of equivalents. Universal and Sandel have each filed motions for summary judgment of non-infringement pursuant to Federal Rule of Civil Procedure Rule 56(c). Under Rule 56(c), summary judgment is appropriate when “the pleadings, depositions, answers to interrogatories, admissions on file, together with affidavits, if any, show that there is no genuine issue as to any material fact and that the party is entitled to judgment as a matter of law.” “Determination of infringement ... is a question of fact.... Thus, summary judgment of non-infringement can only be granted if, after viewing the alleged facts in the light most favorable to the non-movant, there is no genuine issue whether the accused device is encompassed by the claims.” A. Universal’s Motion for Summary Judgment of Now-Infringement Universal makes five arguments that it contends supports summary judgment that its TAWS does not literally infringe claim 1 of the ’436 patent. First, Universal argues that its TAWS does not have an “enabling envelope.” Second, Universal arg-ues that its TAWS uses landing flap or gear signal inputs, which Universal contends the ’436 patent specifically disclaims. Third, Universal argues that its TAWS does not enable a ground proximity warning system. Fourth, Universal contends that its TAWS can not infringe the ’436 patent because the Minimum Ground Clearance Boundary (“MGCB”) of its TAWS is different from the prior art GPWS modes to which ’436 patent claims were alleged to be limited. Fifth, and finally, Universal states TAWS cannot infringe the ’436 patent because its system does not use “heading,” as that term is ordinarily defined. Several of Universal’s arguments in favor of summary judgment fail in light of the court’s claim construction, recited above. Universal’s argument that its TAWS does not use “heading,” as that term is ordinarily defined is unavailing in light of the court’s determination that, in the ’436 patent, “heading” has the same meaning as “bearing”; “the angle formed by the line connecting the aircraft position and the airport and a reference datum.” Universal has presented no argument in support of summary judgment based on “heading” as the court has construed the term. Indeed, at oral argument, Universal conceded that there would be a material question of fact if the court were to construe “heading” to have the same meaning as “bearing.” Universal’s argument that its TAWS cannot infringe the ’436 patent because its MGCB is distinguishable from the prior art GPWS modes also fails in light of the court’s determination that the claims of the ’436 patent are not limited to 'only the particular prior art GPWS referenced in the specification. The court has construed the warning system limitations to mean “a system to monitor the flight conditions of an aircraft and provide a warning if flight conditions are such that an -inadvertent contact with the ground is imminent.” In light of that construction, there remains a material question of fact as to whether Universal’s MGCB reads on that limitation. Similarly,' Universal’s argument that it is entitled to summary judgment of non-infringement because its TAWS uses flap and gear position input also fails as the court has determined that the claims of the ’436 patent are not limited to only systems which do, not use flap and gear input. Universal also argues that because its TAWS is' alleged not to have an “enabling envelope,” and that its system does not “enable” a ground proximity warning system, its TAWS cannot infringe the ’436 patent. According to Universal, “Honeywell has construed the term ‘enabling envelope’ to require an envelope which activates a GPWS when an aircraft is on final [a]pproach without using landing flap or gear signal inputs.” As noted above, the court has determined that the warning system limitations are not limited to the prior art GPWS recited in the ’436 patent specification and that Honeywell’s claimed invention does not exclude from coverage systems which utilize flap and gear position inputs. The court has construed “enabling envelope” to mean “activating or turning on a set of limitations within which an aircraft can perform safely and effectively.” When construing “enabling envelope” the court pointed out that none of the claims recite a limitation requiring a determination of whether an aircraft is on final approach. Therefore, Universal’s only remaining arguments for summary judgment based on the “enabling envelope” limitation are that its TAWS does not enable, or activate, a set of limitations within which an aircraft can perform safely and effectively. Honeywell argues that Universal’s TAWS does just that and points to documentary and deposition testimony purportedly describing “a wedge-shaped area around the airport that activates Universal’s MGCB warning system.” As the court previously noted, the third limitation of claim 1 performs two functions: it calculates the distance of an aircraft from a particular airport and provides an enabling envelope for enabling the warning system as a function of the distance of the aircraft wi