Full opinion text
OPINION THYNGE, United States Magistrate Judge. I. Nature and Stage of the Proceedings This action, which originated as a patent infringement case, involves technology in the aviation industry. The parties are competitors in the market for terrain warning systems and displays. Honeywell International Inc. and Honeywell Intellectual Properties Inc. (collectively, “Honeywell”) manufacture and sell a terrain awareness and warning system, the “Enhanced Ground Proximity Warning System” or “EGPWS.” Since February 29, 2000, Universal Avionics Systems Corp. (“Universal”) manufactures and sells its terrain awareness and warning system, otherwise known as “TAWS.” Sandel Avionics, Inc. (“Sandel”) manufactures and sells a terrain awareness and warning system, the “ST3400 TAWS/RMI.” Honeywell commenced this action on May 10, 2002 seeking monetary recovery and injunctive relief for alleged willful infringement of five patents-in-suit: U.S. Patent Nos. 5,839,080 (“ ’080 patent”), 6,122,570 (“ ’570 patent”), 6,219,592 (“ ’592 patent”), 6,092,009 (“’009 patent”) and 6,138,060 (“ ’060 patent”) against Sandel and Universal. On July 17, 2002, Sandel answered the complaint by denying the allegations of willful infringement, and asserted various affirmative defenses and counterclaims for declaratory relief that the patents-in-suit are invalid and not infringed. On July 19, 2002, Universal responded to the complaint by denying the allegations of infringement and willful infringement and raised various affirmative defenses and counterclaims for declaratory relief that the patents-in-suit are invalid and not infringed. On August 8, 2002, Honeywell replied to the counterclaims of Universal and Sandel. On September 9, 2002, Universal amended its answer by adding counterclaims for attempt to monopolize, tortious interference with business expectations, and unfair competition. Honeywell responded to Universal’s amended counterclaims on October 15, 2002. On February 7, 2003, the parties participated in a tutorial before the court, during which the technology and the matters at issue were addressed. On February 10, 2003, Universal filed a second motion to amend its answer, in which the affirmative defense of inequitable conduct was added. On February 11, 2003, Sandel moved to amend its answer, and also added the affirmative defense of inequitable conduct. On March 18, 2003, the court granted Sandel and Universal’s motions to amend. On February 19, 2003, the parties filed a joint submission on claim construction, which set forth the disputed claims of each patent-in-suit and the position of each party with respect to each term. On March 7, 2003, the parties filed their initial briefs on claim construction detailing their respective claim interpretation positions. The parties’ responsive briefs were filed on April 4, 2003. Pursuant to Markman v. Westview Instruments, Inc., 52 F.3d 967 (Fed.Cir.1995) (en banc), aff'd, 517 U.S. 370, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996) and local practice, a claim construction hearing was held on April 9, 2003. This court construed the disputed claims in a memorandum dated May 30, 2003. The parties then submitted case disposi-tive motions. On July 30, 2003, Sandel filed motions for summary judgment of non-infringement and invalidity of certain claims of the ’060 and ’009 patents based on the prior art. On August 2, 2003, Universal filed a motion for partial summary judgment of non-infringement with respect to the ’080, ’009, ’570 and ’592 patents. On August 27, 2003, Sandel and Universal filed a joint motion for summary judgment of invalidity based on the on-sale and public use bars. Universal also filed a supplemental memorandum in support of San-del’s motion of invalidity, converting it into a joint motion for summary judgment. On September 22, 2003, Honeywell responded to these motions. On September 29, 30 and October 1, 2003, Universal and Sandel filed their reply briefs. In a memorandum issued on October 16, 2003, this court addressed the motions of invalidity based on the prior art. Relying on its position that the court no longer had jurisdiction based on the lack of a case or controversy, Honeywell did not address the challenge of anticipation of certain claims of the ’009 and ’060 patents. Universal and Sandel’s joint motion was granted and denied in part. Left for trial were the invalidity allegations based on the pri- or art regarding claims 27-33 of the ’009 patent and claims 4^5 of the ’060 patent. In a memorandum dated October 28, 2003, this court found that the accused devices did not infringe the asserted claims of the ’080, ’570 and ’592 system patents and the ’009 display patent. Additionally, that opinion determined that San-del’s ST 3400 TAWS did not infringe claim 4 of the ’060 display patent, and held that neither Sandel’s nor Universal’s TAWS contained the “look ahead distance” and “terrain floor boundary” limitations identical to those disclosed and claimed in the ’080 patent, as well as, in the remaining patents-in-suit. Based on this finding, Universal prepared a supplemental memorandum in further support of its motion for summary judgment of non-infringement. This memorandum, filed October 29, 2003, asserted that Universal’s TAWS did not infringe upon the ’060 display patent because it lacked the required warning logic expressed as look ahead distance and terrain floor boundary. Consistent with its previous rulings, this court entered partial summary judgment of non-infringement with respect to claims 4 and 5 of the ’060 patent. As a result, all claims of infringement were dismissed. In a companion filing, Universal moved to change the order of proof at trial. This motion was granted on October 29, 2003. Subsequently, the parties agreed to a bench trial for the remaining issues. Thus, Universal and Sandel assumed the role of plaintiffs for all purposes and are referred to as such in this opinion. The remaining joint motion of invalidity based on the on-sale and public use bars was not decided, and remained an issue for trial. A seven day bench trial was conducted on November 3-7, 10 and 12, 2003. This opinion represents the court’s findings of fact and conclusions of law with respect to all trial issues. This court has subject matter jurisdiction over this action pursuant to 28 U.S.C. §§ 1331 and 1338. Personal jurisdiction and venue are not contested. Incorporated by reference is the construction of the claim terms recited in the May 30, 2003 memorandum and order. II. The Patents-in-Suit The patents-in-suit are designed to solve a problem in the aviation industry known as Controlled Flight Into Terrain (“CFIT”). CFIT refers to a category of accidents that occur when an aircraft is flown into the ground during controlled flight. CFIT crashes generally occur as a result of pilot error and are distinguished from other accidents involving loss of control or mechanical failure because a ground collision is not due to system malfunction or failure. A precursor to the technology described and claimed in the patents-in-suit is the Ground Proximity Warning System (“GPWS”). GPWS uses radar altimeter (also referred to as radio altitude) input to determine if flight conditions are such that inadvertent contact with the terrain is imminent. Because the GPWS is limited to the downward looking radar altimeter, it has certain disadvantages and cannot prevent all CFIT accidents. The patents-in-suit relate to Honeywell’s research and development to improve or “enhance” GPWS. The basic concept of Honeywell’s Enhanced GPWS (“EGPWS”) is that it provides “virtual look ahead ... to be able to actually predict where the airplane was going based on the terrain database and an accurate knowledge of where the aircraft was ....” D.I. 236 at 898:11-899:1. This forward looking capability is intended to provide increased alerting time to warn pilots of potentially hazardous terrain ahead. Honeywell’s EGPWS also gives “the pilot a picture,” that is, a threatening terrain display in addition to a verbal alert. The Limitations of the Challenged Claims The ’080 patent entitled “Terrain Awareness System,” issued to AlliedSignal Inc. on November 17, 1998, was derived from application Serial No. 509,642 (“ ’642 application”). The challenged independent claims of the ’080 patent claim “an apparatus for alerting a pilot of an aircraft of proximity to terrain” and “a method for alerting a pilot of hazardous proximity to terrain.” JTX 1 at 49:1-3, 50:10-11. Claim 1 of the ’080 patent is a representative claim and contains the basic requirements for the claimed terrain alerting system. Claim 1 requires a database of stored terrain information, an input and an output, a signal processing device, a terrain floor boundary, first and second envelopes, which are determined as a function of flight path angle, look ahead distance and a terrain floor boundary, and the means for outputting an alert. It recites an output of at least a single alert and does not require multiple alerts, cautions or warnings. The challenged dependent claims of the ’080 patent add limitations which relate to the display of images of terrain near the aircraft and the output of alerts in the form of sounds or voice call-outs. Id. at 49:48-50:9, 50:33-37, 50:45-47. The ’570 patent, a continuation in part of the ’080 patent, claims a system or a method “for assisting in the prevention of controlled flight terrain accidents.” JTX 2 at 32:24-25, 33:35-36. The challenged claims of the ’570 patent encompass all of the limitations of the independent claims of the ’080 patent, but add the requirement that the alerting system presents a visual display to the pilot of the terrain in the vicinity of the aircraft. Id. at 32:24-33:26, 33:35-34:37. The challenged independent claims of the ’592 patent claim apparatus and methods “for alerting a pilot of an aircraft of proximity to terrain.” JTX 3 at 32:34-35, 33:22-23, 34:14-15. The challenged claims of the ’592 patent encompass all of the limitations of the independent claims of the ’080 patent, and require that the alerting system further define its alert envelopes to include “lateral boundaries” to the sides of the ground track. Id. at 32:34-62, 33:14-53, 34:5-38. The algorithms in the specification allow the system to detect horizontal, as well as, vertical terrain threats. The ’009 patent claims a system, which displays terrain information, as well as, compares the terrain and aircraft altitude. Based on this comparison, certain aspects of the display are colored. The asserted independent claims of the ’009 patent claim, in various forms, relate to a “terrain information system for providing a visual display to the pilot of contours of the terrain proximate to the aircraft.” JTX 4 at 39:5-7, 41:1-2, 41:28-29, 42:1-3, 42:20-21, 42:40^41. Independent claim 27 adds the requirement that the terrain information system include “a visual display to the pilot of warning of terrain proximate to the aircraft.” Id. at 40:24-28. The challenged independent claims of the ’060 patent recite “a warning system for aircraft” and “a method for displaying terrain information to a pilot of an aircraft.” JTX 5 at 38:38, 39:14, 40:1-2. The ’060 patent claims a system that causes certain information, including the severity of an alert, to “pop-up” on the cockpit display under certain conditions. Id. at 38:38-56, 39:14-40:19. The patents-in-suit are directed to solving CFIT and the problems of the prior art systems, in particular GPWS, which was used in a variety of aircraft. The patents, therefore, are not limited to any particular type or class of airplane or jet. Further, none of the challenged claims require any specific amount of alerting time, type of alert or minimum level of allowable nuisance alerts. Moreover, neither the algorithms nor the number of algorithms used to implement the look ahead alerts is a recited limitation of any of the asserted claims. III. Facts-Development of EGPWS Beginning in May 1993, Honeywell, then AlliedSignal, began development of EGPWS. The most accurate historical record produced of the development process of EGPWS are the “Muller-Grams” or “Design Notes.” Hans Muller, deceased, a named co-inventor of the ’080,-’592, ’570 and ’060 patents, authored a four-part series of documents between November 8, 1993 and February 2, 1995 which concerned implementation of this forward looking ground proximity warning system. These documents report and record the progress of the system. For clarity and consistency, these documents are referred to as Design Notes throughout this opinion. The Design Notes are objective, contemporaneous writings of the development of EGPWS. The date on the cover of each set of Design Notes reflect when the writing began. Muller also dated the end of the document when it was completed. As such, Design Notes I was written on November 8, 1993. Design Notes II began on April 7, 1994 and ended April 21, 1994. Design Notes III was written from July 15, 1994 to July 29, 1994. Design Notes IV began on January 26, 1995 and ended February 2, 1995. The diagrams at the end of the Design Notes also bear dates, some of which differ from the inclusive dates of the notes. For example, diagram WX-DET, attached to Design Notes II, contains revision dates which reflect when information was changed on the drawing, although the revisions dates are later than the time covered in this Design Notes. In general, the Design Notes describe the development and implementation of suggestions or proposals to correct or modify the system. Regarding when changes actually occurred, the Design Notes are not entirely clear. They refer to elements already installed and also comment on features to be instituted. For example, Design Notes II only indicates that the detection algorithms for approach and takeoff have been combined. In Design Notes III, some, but not all, of the proposals have been implemented at the time of the writing. Design Notes IV encompasses everything completed in the system at that time, but does not advise when each completion occurred. Despite these shortcomings, they are the most accurate reflection of the status of EGPWS as of the date or dates of each Design Notes. In addition to the Design Notes, Kevin Conner, another named inventor who primarily worked on the software for the system, kept archived copies of the source code for the prototype during the development process. Unfortunately, no versions of the code exist before July 31, 1994. Software development, including coding of the software, also began in May 1993. The first iteration of the alerting algorithms software was created within a few weeks and, as a result, was ready for testing on a laptop computer. Design Notes I■ — November 1993 Design Notes I focuses oh the display of terrain information and discusses terrain display formats, threat displays and the associated algorithms to generate a terrain display on a weather radar display within the limitations imposed by that format. It also provides detail about the “threat display algorithms,” noting that there are two elements to these algorithms, that is look ahead distance/direction and terrain detection (aircraft altitude relative to terrain altitude). Design Notes I is concerned with the relationship and adaption of these elements to the terrain data base and the input signal sources. In this set of the Notes, two algorithms are proposed for terrain detection: an approach algorithm and an algorithm for all other flight modes (non-approach). In addition to a written description of the terrain detection algorithms in the Notes, they are shown in graph form' in Fig. WX-30. Each algorithm contains two alert envelopes (caution-yellow; warning-red), which are functions of look ahead distance and the terrain floor. Design Notes I discusses the reaction time, in relation to appropriate clearance, for a pilot to respond to an alert, and recognizes that at the top of a 30 degree bank angle, the pilot needs adequate clearance from the terrain ahead. As a result, a minimum look ahead distance, that is proportional to the turn radius plus a safety terrain clearance distance plus a distance equivalent to a reaction time of ten seconds, is recommended. Contained in Design Notes I is Fig. WX-31 which calculates the terrain floor height below the aircraft in the system to be “equal to the MKV terrain floor which is 100 feet per mile distance from the runway and limited to 800 feet.” Eventually, this description, after considerable modification and testing, became the basis for the element, terrain floor boundary, in the ’080 patent. Design Notes II — April 1991 As noted previously herein, Design Notes II was written between April 7 and April 21, 1994. The figures attached to the Notes bear, dates of April 19, 1994 and earlier. This writing further describes the development stage of the displays of EGPWS, and advises that a preliminary display has been implement on King Air in which terrain alerts or warnings cause the display to pop-up. The system also allows a pilot to manually call up the display. Design Notes II specifies that “the background terrain display is relative to the aircraft altitude” and suggests, after conducting experiments, a simulating scan conversion process will provide an acceptable display. In Design Notes II, the two algorithms for terrain detection are consolidated for all flight modes. The single algorithm is similar to the non-approach algorithm described in Design Notes I. This change to a single algorithm addressed the problem of the system distinguishing between the two approaches and resulted in a continuous transition between approach and non-approach situations. Design Notes II contains modifications to the terrain clearance floor described in Design Notes I from a constant or continuous slope to a step approach to enhance the detection accuracy. Other changes found in Design Notes II are to the cut-off altitude, the beta sink rate enhancement, which caused modifications of the envelopes, and the background display. These changes were in response to data obtained during in-flight and simulator testing of the system. Design Notes III — July 199k The opening comments of Design Notes III summarize the development, testing and evaluation of the system over the past three to four months, and note that the system has been tested on King Air and in the simulator and demonstrated to a number of people. Most of the engineering concerns during that time focused on debugging the system and the software which were identified in the flight tests and simulator reports. The analysis of the flight test data included radio altimeter behavior in precipitous terrain. Nine areas are listed in the Notes where changes to the system are recommended. It also describes additional proposed changes to the alerting algorithms since Design Notes II, that is, splitting the detection algorithms into two parts in an attempt to cure the problem of the absence of a caution before each warning. Design Notes III describes modifications to the look down envelope in relation to the beta angle enhancement. Lateral boundaries to the look ahead threat detection, originally found in Fig. WX-45A attached to Design Notes I, are further modified in Design Notes III. Figure WX-45A in Design Notes I contains lines offset configurable to a given angle and extending outward. A similar diagram is contained in Design Notes III as Fig. WX-45, which is described as replacing the single threat detection vector, that looks along the aircraft ground track to provide terrain threat detection, with an array of vectors. The purpose of this change was to safeguard against worst case scenarios of errors in either the data base or the GPS. Concerns regarding justification of the applicable algorithm to the FAA were also addressed by the change to an array of vectors. In Design Notes III, the “wedding cake” layered memory is introduced. This change, which modifies the distance of the terrain displayed ahead of the aircraft, was made in response to comments by pilots to expand the look ahead range. To address these concerns and avoid an explosion of variable resolution of the displays of terrain, the wedding cake layered memory was developed whereby the top layer (terrain closest to the aircraft) has the highest resolution and the lower layers, which cover a larger area over a longer distance, have successively less resolution. The wedding cake memory diagram in Design Notes III is Fig. WX-47. Design Notes III also discusses a meeting on July 28, 1994 between Honeywell and Gulfstream to address the interface between the system and the new jet aircraft. Software Development As noted previously herein, the initial software code was sufficiently developed for testing by mid-1993. At that time, the software for the system included features of the display and the look ahead warning algorithms. Shortly after implementation of the original source code, the system’s display featured multiple levels of terrain by using different dot densities to distinguish various terrain elevations. By the end of 1993, the display included color-coding the terrain contours based on the degree of terrain threats, which were yellow for caution and red for warning. At that time, the system also included displaying terrain relative to the aircraft altitude. Therefore, both the relative altitude background and the threat display distinguished by color existed in 1993. In 1993, the first version of the laptop prototype of EGPWS was tested on King Air. Initially, the terrain display was shown on the screen of a laptop computer. Later prototypes showed terrain images on the weather radar display in the King Air airplane. Thereafter, as confirmed in Design Notes I through III, modifications were made to various algorithms and, as a result, to the source code. Aerospatiale Presentation One fact relied upon by Universal and Sandel are the contacts with Aerospatiale. The laptop system was demonstrated to two Aerospatiale research engineers on King Air in 1993. In June 1994, Honeywell presented to Aerospatiale the enhanced system for a joint study program. Under the proposal, Aerospatiale would provide simulator time and pilots to assist in the development of EGPWS. The presentation contained general descriptions of the capabilities of the system. March 8, 1994. Demonstration Flight with Fred George Universal and Sandel point to the George flight in support of their various defenses against the patents. On March 8, 1994, Honeywell demonstrated the EGPWS laptop prototype to Fred George, a pilot and contributing Editor for Business & Commercial Aviation magazine. After the demonstration, George published an article in the June 1994 issue of the magazine. The demonstration consisted of flying two CFIT accident tracks during two night departures, one from San Diego and the other from Palm Springs, California. Steven Johnson, a co-inventor primarily involved in terrain database development and design, computer simulation and flight testing, and Conner demonstrated the laptop EGPWS prototype during the flight. After the demonstration, Conner noted that the prototype software functioned reasonably well within its expected behavior during the demonstration. The George article clearly indicates that the system is in its development phase. The article notes that the demonstration focused primarily on the vicinity around the airports. It points out that the technology includes an airport-vicinity database with a highly precise flight management system, which allows the pilot to view on a display screen the aircraft’s position in relation to terrain obstructions. The article discusses a terrain clearance floor (“TCF”) which is an outgrowth of envelope modulation that was introduced in 1984. It describes TCF as a bottom-line terrain avoidance feature which provides a gradual series of warning buffers over the terrain elevation contours within a 30 mile radius from the airport. The article contains a diagram of TCF. The March 199U Demonstration Video In late March 1994, Rawlins Production created a video which shows the functions of the system on King Air in several scenarios. The video depicts three demonstrations of EGPWS aboard King Air. It shows the displays and alerts generated by the laptop prototype and demonstrates that the system provided both caution and warning alerts in advance of the traditional GPWS warnings which are also recorded on the video. The system on the film provided two alerts in the proper order. Demonstration Flight Program Between late 1993 through mid-1994, approximately 150 people associated with the aviation industry, including individuals from the FAA, observed the system during demonstration flights on King Air. These flights have been referred to as “show- and-tell” flights. . The demonstration flight program served to educate the aviation community regarding the safety enhancements in the proposed system which would prevent or substantially reduce CFIT accidents. It also served to advise potential customers of Honeywell’s new system. Participants in the flight demonstrations were given questionnaires to complete. As a result, the demonstrations of the laptop system provided feedback regarding human factors, cockpit integration and pilot acceptance issues. Honeywell reviewed and used this information during its development of EGPWS, including for verification of the system. The questionnaires and other feedback from the flight demonstrations were discussed during the weekly development meetings throughout 1994, as evidenced in Design Notes III. Observers were not required to sign confidentiality agreements, however, they did not have any direct contact with or control over the laptop computer or the software data. Participation in the demonstration flights was by invitation only. Flight Testing and Simulations Another factor relied upon by Universal and Sandal is the quantity of testing of the system by Honeywell. During the development of EGPWS, Honeywell ran thousands of simulations and hundred of flight tests. In a memorandum dated June 16, 1994, Johnson outlined the status of the testing. As of this date, the system, more specifically the alerting algorithms, through simulation or on King Air, had been tested against eleven known nuisance alert scenarios and fourteen known accidents. Johnson’s memo advises that additional testing data is needed to evaluate the look ahead algorithms because during some of the prior test flights and demonstrations, the warnings failed to occur. Data, such as test scripts, terrain files and other materials, were required for certain problem airports and other CFIT accidents. Gulfstream and Collins Documents Heavily relied upon at trial by Universal and Sandel are the various documents generated from January into July 1994 between Honeywell and Gulfstream Aerospace (“Gulfstream”) and Honeywell and Collins Commercial Avionics (“Collins”) regarding Honeywell’s offers to sell its Enhanced Ground Proximity Warning System. In 1994, Gulfstream and Canadair Global Express (“Canadair”) launched developmental luxury airplane programs. On January 6, 1994, Gulfstream issued a Request for Proposal (“RFP”) to Honeywell for 108 shipsets of GPWS for its new jet aircraft, Gulfstream V or G5, program. The RFP emphasized the importance of integration, noting the need to minimize clutter and properly consolidate existing systems into a new cockpit. In response, Donald Bateman, chief engineer for Honeywell’s flight safety systems division, made a presentation to Gulfstream on January 11, 1994. The presentation focused on the performance features of an enhanced GPWS which was under development, and described the future system as including various levels of visual and aural alerts, terrain data, cockpit displays with increasing dot densities for at least three levels of terrain, alert envelopes, human factors issues associated with cockpit integration and an enhanced weather radar for areas not covered by the database. After the presentation, Honeywell followed up with a letter to Gulfstream on January 21, 1994 emphasizing that the proposed system uses a “specialized terrain data base, together with aircraft position, altitude and velocity information, to provide a view of threatening terrain in a clutter-free manner on existing navigation and weather displays.” It specifically noted that Honeywell was interested in testing the system’s potential terrain display enhancements on the Gulfstream IV test aircraft in the spring and summer of 1994. On February 4, 1994, Honeywell sent a proposal, with extensive attachments, offering to sell its new system to Gulf-stream. In the proposal, Honeywell offers EGPWS as the primary unit, with GPWS as an alternative and quotes various prices for delivery of the system during the years 1995 through 1999. The pricing for either system is similar. The attachments include a Management Volume, Cost Proposal and a Technical Proposal. The Technical Proposal contains eight sub-attachments. The resumes of the key personnel are in attachment A. Attachment B provides the technical description of the enhanced system, including descriptions of terrain ahead alerting, terrain awareness display and terrain clear-anee floor, hardware features, a main processor, input and output signals and audio warning and alert output signals. It details a display of terrain information on the weather radar display. Attachment C is a product specification for the system’s computer. Attachment D is a compliance matrix/system requirements document, while attachment E is the compliance matrix/statement of work document. Attachment F consists of engineering drawings. Attachment G is the program schedule for the Gulfstream V aircraft. Attachment H contains the software requirement specifications for the envelope modulation database. Although a substantial amount of technical information is provided, not included is a product specification for EGPWS. Section 7.0 of the proposal notes that a specification will be prepared to define the performance requirements of the enhanced system, with only preliminary performance requirements contained in attachment B. However, a product specification for GPWS is included. Negotiations continued between Honeywell and Gulfstream until July 7, 1994 when they executed a Memorandum of Agreement (“MOA”) regarding EGPWS, also known as part no. 956-0976-001. The MOA contains specific terms and conditions consistent with the original proposal, provides delivery schedules, packaging, shipping and warranties and specifies that it supercedes any and all previous communications, representations or agreements regarding the system. It reflects a price of $83,565.00 per unit. The MOA does not contain some of the typical provisions in aviation contracts, such as price penalties for a failure to provide adequate research and development support, the specific levels of engineering resources required from Gulfstream or any standards for the flight test program to evaluate EGPWS. Despite the absence of these provisions, Gulf-stream issued a purchase order which Honeywell acknowledged on November 18, 1994. During the same time period, Honeywell proceeded in parallel negotiations with Collins. Collins, who was bidding to provide cockpit avionics and other aeronautical devices to Canadair, solicited Honeywell on February 18, 1994 regarding its GPWS for the Canadair program. On March 18, 1994, Honeywell responded with a proposal that contained the same information, provisions and terms that previously had been provided to Gulfstream. No contract of sale was ever executed between Honeywell and Collins. Design Notes IV — January 26 to February 2, 1995 The final set of the Design Notes was completed on February 2,1995. It reports on the resolution of the issues and changes identified in Design Notes III and discusses the interface and integration issues resolved and those that remain. The inventors clearly felt at the time of Design Notes III that significant problems with the system still existed. One issue was the wedding cake formula which related to the stored terrain database. Because of nuisance alarms, changes to the formula were made after Design Notes III. Other matters addressed were changes in the number of threat detection vectors for the implementation of the lateral boundaries and modifications to the look-up envelope, the beta sink rate enhancement and the cut-off altitude. According to Design Notes IV, as a result of continued testing, the cut-off altitude was changed to solve the “runway on a cliff’ situation. Modifications to the beta angle enhancement were made to address the missing cautions problem — a difficulty that arose from changes to the look ahead distance and threat envelopes. The effectiveness of the displays and the auditory warnings to the flight crew remained a significant concern as noted in Design Notes III and adjustments to this part of the system occurred thereafter as indicated in Design Notes IV. IV. On-Sale and Public Use Bars Universal and Sandel assert that the inventions recited in the challenged claims of the patents-in-suit were on-sale and/or in the public use one year prior to the filing date of the ’080 patent, and therefore, the patents are invalid. This date, July 31, 1994, is referred to as the “critical date” for application of the § 102(b) on-sale and public use bars. 35 U.S.C. § 102(b) describes the public use bar and on-sale bar to patentability. A finding that a section 102(b) bar invalidates a patent must be based on clear and convincing evidence. See Netscape Communications Corp. v. Konrad, 295 F.3d 1315 (Fed.Cir.2002). The Patent Act endows patents with a presumption of validity. See 35 U.S.C. § 282 (2002). “The burden of proving invalidity always remains with the party asserting invalidity; the burden never shifts to the patentee.” Harrington Mfg. Co. v. Powell Mfg. Co., 815 F.2d 1478, 1482 (Fed.Cir.1986). Nevertheless, there are differences in the analysis of the two bars: the public use bar focuses on the public’s reliance on an invention that is thought to be in the public domain, while the on-sale bar centers on any commercialization beyond the one year grace period. See Western Marine Electronics, Inc. v. Furuno Elec. Co., Ltd., 764 F.2d 840, 844 (Fed.Cir.1985) (“In essence, the policies underlying the bar[s] ... define [them].”). The on-sale bar allegations are based on three pre-critical date proposals and one pre-critical date MOA made to third parties in connection with the development of two new aircrafts: the Gulfstream V and the Canadair Global Express. The parties dispute whether these proposals — and in relation to the Gulfstream V proposal, the corresponding MOA — embody the claimed inventions and whether the inventions were ready for patenting as of the time the Honeywell products were offered for sale. Universal and Sandel also allege that the inventions recited in the challenged claims of the patents-in-suit are invalid under Section 102(b) public use. Universal and Sandel assert that the claimed inventions were in public use based on a number of demonstration flights that occurred on Honeywell’s King Air aircraft prior to the critical date. The flights in question began in 1993 and continued beyond the critical date, the majority of which occurred between March 8,1994 and July 31,1994. One flight of particular interest is the George flight on March 8, 1994. The parties dispute whether this flight constituted an invalidating public use. The subsequent article regarding this demonstration, published in the June 1994 issue, is the focus of the dispute. Needless to say, Honeywell disputes that its patents are invalid on any basis, including Section 102(b). Honeywell argues that the evidence supports a conclusion that the patents-in-suit are valid pursuant to the experimental use exclusion to Section 102(b). Otherwise stated, Honeywell contends that, the evidence on which Universal and Sandel rely, was necessary to determine whether EGPWS, and therefore, the patents-at-issue, would work for its intended purpose in the intended environment. On-Sale Bar The ultimate determination that a product was placed on sale under 35 U.S.C. § 102(b) is a question of law, based on the underlying facts of the case. See Ferag AG v. Quipp, Inc., 45 F.3d 1562, 1566 (Fed.Cir.1995). On-sale bar prevents an inventor from patenting an invention that he has commercially exploited beyond the statutory term, that is, more than one year prior to filing of the patent application. See Continental Plastic Containers v. Owens Brockway Plastic Prod., Inc., 141 F.3d 1073, 1077 (Fed.Cir.1998). It prohibits patent protection to inventions that have been placed in the public domain through commercialization. See Abbott Labs. v. Geneva Pharms., Inc., 182 F.3d 1315, 1319 (Fed.Cir.1999) (citations omitted). A two-part test, as set forth in Pfaff v. Wells Electronics, Inc., 525 U.S. 55, 67, 119 S.Ct. 304, 142 L.Ed.2d 261 (1998), is employed for determining when the on-sale bar is triggered. Pfaff requires that (1) the invention be the subject of a commercial sale or offer for sale and that (2) the invention be “ready for patenting” at the time of the offer to sell or sale. Even a single offer is sufficient to invalidate the patents. Id. An accused infringer may overcome a patent’s presumption of validity by presenting clear and convincing evidence of facts showing that the patented device was on-sale before such critical date. See Massey v. Del Labs., Inc., 118 F.3d 1568, 1573 (Fed.Cir.1997). Both prongs must be proven by this standard and must occur before the critical date. See EZ Dock, Inc. v. Schafer Sys., Inc., 276 F.3d 1347, 1351 (Fed.Cir.2002). Subject of Commercial Offer for Sale Universal and Sandel contend that Honeywell’s EGPWS was the subject of a commercial sale no later than July 7, 1994 — 24 days prior to the critical date. Honeywell strongly disputes this contention. Under Pfaff, the first consideration is whether the claimed invention is the subject to a commercial offer for sale, which requires clear and convincing evidence that the subject of the offer for sale met each limitation of the claim. See Pfaff, 525 U.S. at 67,119 S.Ct. 304 (indicating a § 102(b) analysis includes whether the “subject of the barring activity met each of the limitations of the claim, and thus was an embodiment of the claimed invention”); see also, Scaltech Inc. v. Retec/Tetra, L.L.C., 178 F.3d 1378, 1383 (Fed.Cir.1999); KeyStone Retaining Wall Sys. Inc. v. Westrock, Inc., 997 F.2d 1444, 1451-52 (Fed.Cir.1993); Orthokinetics, Inc. v. Safety Travel Chairs, Inc., 806 F.2d 1565, 1572-73 (Fed.Cir.1986); B.E. Meyers & Co., Inc. v. U.S., 47 Fed.Cl. 200, 204, 206 (Fed.Cl.2000); Casco Prods. Corp. v. Knapp-Monarch Co., 270 F.Supp. 320, 322 (D.Del.1967). The analysis requires a careful examination of the purpose of the use contemplated in a possible barring sale. Only an offer in which the “other party could make into a binding contract by simple acceptance” constitutes an offer for sale for invalidity based on the on-sale bar. Netscape Communications Corp., 295 F.3d at 1323 (quoting Group One, Ltd. v. Hallmark Cards, Inc., 254 F.3d 1041, 1047 (Fed.Cir.2001), cert. denied, 534 U.S. 1127, 122 S.Ct. 1063, 151 L.Ed.2d 967 (2002)); see also, Rhenalu v. Alcoa Inc., 224 F.Supp.2d 773, 801 (D.Del.2002). The court must find that there is a “commercial offer” for sale and that the offer is for the patented invention. Scaltech Inc., 269 F.3d at 1328. “In any given circumstances, who is the offeror, and what constitutes a definite offer, requires looking closely at the language of the proposal itself.” Group One, Ltd., 254 F.3d at 1047 (citing Restatement (Second) of Contracts §§ 24, 26 (1981)). Application of on-sale bar is precluded when aspects of the invention are developed after the critical date. See Space Systems/Loral, Inc. v. Lockheed Martin Corp., 271 F.3d 1076, 1079 (Fed.Cir.2001). However, changes to a product that do not address the matter claimed, will not preclude the application of the on-sale bar. New Railhead Mfg., LLC v. Vermeer Mfg., Co., 298 F.3d 1290, 1297-98 (Fed.Cir.2002) (finding that perfecting or completing an invention to the point of determining that it will work for its intended purpose ends with an actual reduction to practice). Moreover, the delivery of goods subject to the offer need not occur prior to the critical date. See e.g., STX, LLC v. Brine Inc., 211 F.3d 588, 590 (Fed.Cir.2000) (finding delivery dates after the critical date irrelevant where an offer to sell or a sale transpired before the critical date). Accordingly, this first prong of Pfaff requires that the sale be for a commercial and not an experimental purpose. Pfaff, 525 U.S. at 64, 119 S.Ct. 304 (“The law has long recognized the distinction between inventions put to experimental use and products sold commercially.... [A]n inventor who seeks to perfect his discovery may conduct extensive testing without losing his right to obtain a patent for his invention—even if such testing occurs in the public eye.”); EZ Dock, Inc., 276 F.3d at 1352 (“In Pfaff, the Supreme Court expressly preserves the experimental use or sale negation of the section 102 bars.”); see also, Monon Corp. v. Stoughton Trailers, Inc., 239 F.3d 1253, 1258 (Fed.Cir.2001) (“Evidence that the public use or sale of the patented device was primarily experimental may negate an assertion of invalidity.”); Manville Sales Corp. v. Paramount Sys., Inc., 917 F.2d 544, 550 (Fed.Cir.1990) (“A sale that is primarily for experimental purposes, as opposed to commercial exploitation, does not raise an on sale bar.”). The experimental use exception does not apply to experiments performed with respect to unclaimed features. See In re Smith, 714 F.2d 1127, 1136 (Fed.Cir.1983). Thus, when assessing commercial versus experimental sale, under the first prong of Pfaff, the issue is whether the transaction constituting the sale was “not incidental to the primary purpose of experimentation,” which requires evaluating the nature or purpose of the particular use of the invention at the time of sale, based on an objective analysis of the facts surrounding the transaction. See Scaltech, Inc., 178 F.3d at 1385; Seal-Flex, Inc. v. Athletic Track & Court Constr., 98 F.3d 1318, 1323 (Fed.Cir.1996). The inventor’s subjective intent to experiment has “minimal value.” Paragon Podiatry Lab., Inc. v. ELM Labs., Inc., 984 F.2d 1182, 1186 (Fed.Cir.1993). Adequate proof of experimental use negates the statutory bar. Gould Inc. v. United States, 217 Ct.Cl. 167, 579 F.2d 571, 583 (1978) (Experimentation evidence includes “tests needed to convince [the inventor] that the invention is capable of performing its intended purpose in its intended environment.”); see also, EZ Dock, 276 F.3d at 1352. Case law recognizes that substantial testing in a particular environment is often required to ensure that the invention works for its intended purpose. See Kolmes v. World Fibers Corp., 107 F.3d 1534, 1540 (Fed.Cir.1997). When an inventor can show changes during experimentation, which result in features later claimed in the patent application, such evidence strongly demonstrates that the pre-application activities of the inventor negated any evidence of premature commercial exploitation of an invention ready for patenting. EZ Dock, 276 F.3d at 1353. When distinguishing commercial from experimental sales, the court must consider a variety of factors including: (a) the necessity for public testing; (b) the amount of control over the experiment retained by the inventor; (c) the nature of the invention; (d) the length of the test period; (e) whether payment was made; (f) whether there was a secrecy obligation; (g) whether the records of the experiment were kept; (h) who conducted the experiment; (i) the degree of commercial exploitation during testing; (j) whether the invention reasonably requires evaluation under actual conditions of use; (k) whether testing was systematically performed; (l) whether the inventor continually monitored the invention during testing; and (m) the nature of the contacts made with potential customers. Baker Oil Tools, Inc. v. Geo Vann, Inc., 828 F.2d 1558, 1564 (Fed.Cir.1987); Seal-Flex, 98 F.3d at 1323. The court finds that the subject matter of the offers to Gulfstream, Collins and predecessor Honeywell Inc. reflect an early conception of the EGPWS, which did not embody the claimed inventions. Honeywell proposed “the Enhanced MKV” to take advantage of the testing and experimentation opportunities that resulted from these new aircraft development programs. The only pre-critical date offers Honeywell made were for these new aircraft projects, which supports that EGPWS was still in the developmental stages. The Gulfstream and Collins proposals were for an aircraft terrain ahead alerting system based on FMS (Flight Management System) or GPS (Global Positioning System) derived position information and stored terrain data. A component of the system was a terrain clearance floor. Although this element varied based upon distance to the runway, it relied on a radio altitude alert boundary which would cause a display message and oral announcement if the radio altitude became less than the minimum safety clearance. It was not part of the forward looking system as required by the ’080 patent. The proposals described an alerting logic, similar to the one outlined in Design Notes I, which is fundamentally different from the patents-in-suit because the system in the proposals does not use flight path angle to modify the alert envelopes.. Rather, two different envelopes using approach and non-approach algorithms, which are not functions of flight path angle, are recommended. Universal and Sandal argue that Honeywell’s further development did not directly relate to the claims at issue, but rather to unclaimed elements of the system. However, the manner of the continued development and testing that occurred is the type necessary to determine whether this invention would work for its intended purpose in its intended .environment, which has been repeatedly endorsed in cases finding experimental use. Human factors, integration and the other issues involved in the development and testing of the EGPWS were not related only to the Gulf-stream and Canadair jets — as implied by Universal and Sandal — but had broad and significant application to any aircraft, old or new. The challenges that accompany a new flight safety system, which involved the application of new alerting algorithms, a new terrain database and new display functions and needed to be incorporated in existing cockpit systems are clearly significant. Moreover, since both projects involved experimental aircraft, uncertified equipment, such as EGPWS, may be installed for testing. Being involved in these programs would allow Honeywell to review, evaluate, modify and continue developing the technology for the system in a flight regime — the actual environment of the inventions. The experimental use exception is not eliminated by pointing to an offer, understanding or acceptance of commercial terms — including a firm fixed price. The facts at trial reveal that the details of these commercial terms — including the offer of a below market price, the proposed EGPWS under development and the explicit lack of certain specifications — corroborate the experimental purpose of the offers. Although the offers include commercial terms, which as to Gulfstream, ultimately resulted in a contract to supply EGPWS, Honeywell originally offered EGPWS as an alternative to GPWS, which would be used in the new aircraft if EGPWS was not fully developed. The commercial provisions, upon which Universal and Sandal rely, apply regardless of the system that was ultimately supplied. Additionally, Honeywell and Gulfstream had previously worked together on improvements to air safety, specifically on the CFIT problem, which further supports experimental use. Moreover, at the time of and long after the critical date, Honeywell continued to sell GPWS to other customers as evidenced by the proposal to Singapore Airlines in October 1994 — two months after the critical date. No mention of EGPWS is contained in that proposal. The developmental status of EGPWS is further confirmed by the difficulties that Honeywell experienced in selling GPWS during this time. Documents show that customers did not wish to purchase GPWS in light of the future availability of EGPWS. In fact, Honeywell offered “trade-ins” of GPWS units when EGPWS became available. Although “commercial offers” for sale were made to Gulfstream, Collins and Honeywell Inc., the burden of proof required has not been met in light of the experimental nature of Honeywell’s pre-critical date activities relating to the Gulf-stream and Canadair programs. Moreover, while Honeywell offered to sell its existing Enhanced GPWS product, the claimed inventions were not offered for sale. Therefore, the first prong of Pfaff has not been met. Ready for Patenting Notwithstanding the conclusions set forth above, the court will continue with the Pfaff analysis. Under the second prong of Pfaff, an invention is ready for patenting if, prior to the critical date, there is either a reduction to practice of the invention, or sufficiently specific drawings or other descriptions of the invention that allow one skilled in the art to practice the invention. See EZ Dock, Inc., 276 F.3d at 1352; see also, Abbott Labs., 182 F.3d at 1318 (“The fact that the claimed material was sold ... in which no question existed that it was useful means that it was reduced to practice.”), (emphasis added). Universal and Sandel assert that the Pfaff standard has been met as the claimed inventions were ready for patenting in two ways — they were reduced to practice and described in an enabling written description prior to the critical date. Honeywell argues that Universal and San-del have not shown by clear and convincing evidence that any enabling written descriptions of the claimed inventions existed or that the inventions were reduced to practice at any time before the critical date. The inventors conceived of the inventions described and claimed in the.patents during development of EGPWS. A “prototype EGPWS” embodied in a laptop computer was tested on Honeywell’s King Air aircraft. The laptop computer contained software, which executed algorithms to detect terrain alerts and to display images of the surrounding terrain. Work on the system, including color-coding and software developing, began in May 1993. Within a few weeks, the first alerting software was ready for testing in a laptop system. By the end of 1993, display features, including color-coding based on terrain relative to aircraft altitude, existed. Universal and Sandel argue that the inventions set forth in patents-in-suit were reduced to practice in the form of this laptop prototype EGPWS prior to the critical date. As evidence of the reduction to practice, Universal and Sandel rely on internal Honeywell documents tracking EGPWS development, referred to and previously described herein as the Design Notes; technical descriptions provided to third parties Gulfstream, Collins and Ae-rospatiale; pictures and notes associated with the use of the laptop prototype on the King Air aircraft in Bateman’s notebook; a demonstration version of the EGPWS software dated May 18, 1994; a videotape of EGPWS filmed in March of 1994; the Business & Commercial Aviation International article published in June 1994, describing the demonstration flight on March 8, 1994; the testimony of certain Honeywell witnesses and the testimony of Sandel’s technical expert, Robert Gibson. Honeywell disputes that the claimed inventions were reduced to practice as of the critical date because they remained the subject of experimentation. Honeywell argues that the invention could not have been reduced to practice any time before the critical date in light of the evidence just before and shortly after that date including: Design Notes III completed two days before the critical date, in which nine areas are identified by the inventors where changes are necessary due to the data obtained as a result of the testing and demonstrations of the system during the preceding three to four months; Bate-man’s Weekly Engineering Meeting memo of August 1, 1994, the day after the critical date, and each subsequent memo during the month of August 1994, which indicate that the engineers continued to test and evaluate the new algorithms suggested in Design Notes III; Muller and Conner’s memos in December 1994 advising of continued problems as identified in Design Notes III; and Johnson’s memo of June 22, 1994, which summarizes the state of testing and indicates that adequate or complete validation of the algorithms in numerous, additional accident, incident and airport scenarios is needed to determine whether the invention would work for its intended purpose. His memo directly relates to concerns regarding the accuracy of the terrain database. Honeywell also relies on the testimony of its witnesses, Daly, Bateman, Conner and Johnson, who did not consider the invention as operational for its intended purpose as of the critical date. Honeywell likewise cites to the opinion of its technical expert, Dr. John Hansman, who testified that Honeywell only succeeded in developing EGPWS because of its significant testing of the invention. Universal and Sandel also assert that prior to the critical date, the claimed inventions were described in writing by the inventors in sufficient detail, to allow one of ordinary skill in the art to practice them without undue experimentation. In support, they rely upon two groups of documents: Design Notes I, II and III and the technical descriptions and proposals made to Gulfstream, Collins and Aerospatiale prior to the critical date. Honeywell contends that Design Notes I through III are not, at any time before the critical date, enabling descriptions of the claimed inventions. Moreover, Honeywell maintains that the technical descriptions forwarded to Gulfstream, Collins and Aerospatiale are not for the claimed inventions, and therefore could not be enabling descriptions. Reduction to Practice Reduction to practice involves proof that an invention will work for its intended purpose. See EZ Dock, 276 F.3d at 1352. Reduction to practice “may require testing, depending on the character of the invention and the problem that it solves.” Slip Track Sys., Inc. v. Metal-Lite, Inc., 304 F.3d 1256, 1265 (Fed.Cir.2002). There can be no reduction to practice until the invention is sufficiently tested to demonstrate that it would work for its intended purpose. See Space Systems/Loral Inc., 271 F.3d at 1080. Like evidence of experimentation sufficient to negate a statutory bar, reduction to practice involves proof that an invention will work for its intended purpose in its intended environment. EZ Dock, 276 F.3d at 1352 (citing Scott v. Finney, 34 F.3d 1058, 1061 (Fed.Cir.1994)). As discussed previously, the continued testing of the Honeywell product was to determine whether the inventions will function for their intended purpose in the intended environment. This testing includes the study of human factors and cockpit integration issues associated with introducing new information into a cockpit, as well as, testing the algorithms against numerous accident, incident and airport approach data to insure the issuance of appropriate alerts and the minimization of nuisance alerts. There is no indication that this type of testing, in particular for a new safety alert system, is uncommon in the aviation industry. The claimed inventions were developed to improve upon GPWS and to provide warnings in scenarios that were not possible with existing systems. This involved a number of challenges, including designing “threat” detection algorithms, which directly relate to the operation of the alerting envelopes and the functions of flight path angle, look ahead distance and terrain floor boundary, disputed terms in claim 1 of the ’080 patent, determining how the information would be displayed, determining how the information and system would be integrated into existing cockpits and how to obtain the necessary input data, which is directly related to receiving “signals representative of,” another disputed limitation of claim 1 of the ’080 patent. Moreover, language in the specification of the ’080 patent emphasizes that purposes of the invention include a terrain awareness system which issues appropriate warnings while minimizing nuisance warnings and provides both a look ahead/look down and a look up terrain advisory and warning indications to the flight crew of hazardous conditions based upon the predicted trajectory of the aircraft. Without such improvements, the claimed inventions would not work properly. Universal and Sandel’s heavy reliance on contemporaneous documents before and shortly after the critical date does not sufficiently prove a reduction to practice of the claimed inventions. By July 1994, the system was capable in many circumstances of recognizing certain inputs, including information from an on-board terrain database, and generating caution and warning alerts. However, this does not establish, clearly and convincingly, that the inventions were working for their intended purpose in the intended environment. As noted before, the proposals for sale of the system would allow Honeywell to test the inventions in the operating environment and address such “intended environment” issues as proper integration into existing systems in the cockpit, minimization of clutter to provide clear, unambiguous information to the flight crew, avoid impairment of the displays for navigation, weather, predictive windshear and traffic data and their associated alerts and ascertain whether the terrain alert warnings of the inventions were distinguishable from these other alerts. The testimony at trial shows that continued experimentation was necessary to test certain algorithms of the alerting elements and to collect and analyze the resulting data. Such testimony is supported by documents including the pre-critical date Design Notes, which detail Honeywell’s work and progress on EGPWS. Design Notes III was completed two days before the critical date, and enumerates serious concerns about the system that required changes. Although some of those changes had been implemented, while others had not as of the time of Design Notes III, all required additional testing as evidence by Conner’s testimony, Johnson’s memorandum in June 1994 and Design Notes I through III. Finally, Bateman’s meeting agenda notes of August 1994 document that a remaining unresolved task, recommended in Design Notes III, was the review of the warning algorithms and the latest terrain display, both of which directly relate to the asserted claims. They confirm regular evaluation and testing of the various changes proposed in Design Notes III, such as review and debugging of the wedding cake terrain algorithms, and review of the status of the airport terrain data and of accident terrain data models. They acknowledge further modifications to the wedding cake software and validations of new algorithms as a result of flight demonstrations. Such evidence confirms that additional testing was necessary to determine whether the system functioned properly,. and whether the inventions had been reduced to practice. The inventors testified regarding the specific changes made to the system after the critical date. Johnson testified, consistent with his June 1994 memorandum, that the proposed changes in Design Notes III had to be tested through s