In the United States Court of Federal Claims

No. 14-513

(Filed: 30 October 2020*)

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THALES VISIONIX, INC., *

*

Plaintiff, *

*

v. *

* Patent infringement; claim construction;

THE UNITED STATES, * Markman hearing; plain and ordinary 

* meaning; prosecution disclaimer.

Defendant, *

*

and *

*

ELBIT SYSTEMS OF AMERICA, LLC, *

*

Third-Party Defendant. *

*

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Meredith M. Addy, AddyHart P.C., of Atlanta, GA, with whom were Daniel I. Konieczny

and Katherine M. O’Brien, Tabet DiVito & Rothstein LLC, both of Chicago, IL, for plaintiff. 

Charles A. Pannell III, AddyHart P.C., of Atlanta, GA, and Benjamin M. Cappel, AddyHart 

P.C., of Chicago, IL, of counsel. 

Carrie Rosato, Trial Attorney, Commercial Litigation Branch, Civil Division, 

Department of Justice, with whom were Joseph H. Hunt, Assistant Attorney General, Gary L. 

Hausken, Director, and Scott Bolden, of counsel, all of Washington, DC, for defendant. Andrew 

P. Zager, Department of Navy, of Washington, DC, of counsel. 

Kurt G. Calia, Covington & Burling LLP, of Palo Alto, CA, with whom were Ranganath 

Sudarshan, Matthew Kudzin, and Rajesh Paul, Covington & Burling LLP, all of Washington, 

DC, for third-party defendant Elbit Systems of America, LLC. 

CLAIM CONSTRUCTION OPINION AND ORDER

* This opinion was originally filed under seal on 27 October 2020 pursuant to the protective order in this case. The 

Court provided the parties 3 days to submit proposed redactions, if any, before the opinion was released for 

publication. On 30 October 2020, the parties filed a joint notice informing the Court no party seeks redaction of the 

claim construction opinion and order. See Notice with Respect to Sealed Order, ECF No. 183. The opinion is now 

reissued for publication in its original form.
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Plaintiff Thales Visionix, Inc. accuses the government of patent infringement. The 

government noticed a series of subcontractors involved in the development of the technology, 

including Elbit Systems of America, LLC (“Elbit”). Elbit joins the government in defending the 

claims of patent infringement. Following a series of discovery-related disputes, the Court set a 

briefing schedule for the parties to resolve all claim construction disputes. The parties were able 

to resolve the construction of several terms amongst themselves. Once briefing was complete on 

the remaining three claim terms, a Markman hearing on claim construction was held. This Claim 

Construction Opinion and Order construes the disputed terms. 

I. Background 

A. Factual and Procedural History 

Plaintiff is the owner of U.S. patent no. 6,474,159 (“the '159 patent”). Compl. ¶ 11. The 

'159 patent relates to technology regarding the “inertial tracking of objects for head mounted 

displays,” such as those used by aircraft pilots. Id. ¶¶ 4, 12. Conventional systems used in 

inertial tracking typically “measure head motion relative to a reference frame that is stationary 

relative to the ground.” Id. ¶ 12. The '159 patent, however, relates to a system “using inertial 

trackers to track motion relative to a moving platform instead of relative to the earth.” Id. 

Plaintiff accuses the government of infringing the '159 patent by utilizing systems covered by 

this alleged “new method” in the F-35 Joint Strike Fighter tactical fighter jet. See id. Plaintiff’s 

complaint was filed 16 June 2014. The government noticed Elbit as a subcontractor involved in 

the development of various components implicated in plaintiff’s infringement allegations. See 

Notice to Third Parties, ECF No. 132. Elbit jointed this case by filing an answer to the 

complaint on 9 December 2014. See Elbit Systems of America, LLC’s Answer and Affirmative 

Defenses to Pl. Thales Visionix, Inc.’s Compl., ECF No. 16. 

This case has a long and complex procedural history, which the Court discussed in great 

detail in its 6 April 2020 Order resolving the parties’ discovery dispute. See Thales Visionix, Inc. 

v. United States, 149 Fed. Cl. 38, 42–44 (2020) (“Thales Disc. Order” or “the 6 April Order”). 

In the 6 April Order, the Court ordered Elbit to produce source code and a series of technical 

documents for specific modules of the accused system identified in plaintiff’s supplemental 

document requests. Id. at 64. Following a meet and confer by the parties and a subsequent 

status conference, the Court ordered the following: (1) Elbit was given a timeline to produce the 

documents identified in the 6 April Order; (2) the previous scheduling order limiting discovery to 

the issue of infringement was mooted, permitting the parties to seek discovery amongst 

themselves on all remaining issues in this case; (3) third-party discovery was stayed; (4) 

consideration of Elbit’s motion for summary judgment and motion for Rule 11 sanctions were 

stayed; (5) consideration of plaintiff’s cross-motion pursuant to Rule 56(d) was stayed; and (6) a 

schedule for claim construction was set. See Order, ECF No. 149.

On 12 June 2020, the parties filed an initial joint claim construction chart. See Joint 

Claim Construction Chart, ECF No. 154. Following a meet and confer, the parties filed an 

updated joint claim construction chart on 1 July 2020. See Am. Joint Claim Construction Chart, 

ECF No. 158. On 3 July 2020, the parties filed their opening claim construction briefs. See 

Defs.’ Opening Claim Construction Br., ECF No. 159 (“Defs.’ Op. Cl. Constr. Br.”) (the 
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government and Elbit jointly submitted all briefing on claim construction); Opening Claim 

Construction Br. of Pl. Thales Visionix, Inc., ECF No. 160 (“Pl.’s Op. Cl. Constr. Br.”). On 27 

July 2020, the parties filed their responsive claim construction briefs. See Pl. Thales Visionix, 

Inc.’s Resp. Claim Construction Br., ECF No. 165 (“Pl.’s Resp. Cl. Constr. Br.”); Defs.’ Resp. 

Claim Construction Br., ECF No. 166 (“Defs.’ Resp. Cl. Constr. Br.”). On 7 August 2020, the 

parties filed their reply briefs. See Defs.’ Reply Claim Construction Br., ECF No. 168 (“Defs.’ 

Reply Cl. Constr. Br.”); Pl. Thales Visionix, Inc.’s Reply Claim Construction Br., ECF No. 169 

(“Pl.’s Reply Cl. Constr. Br.”). On 27 August 2020 the Court informed the parties of its 

preliminary construction of the disputed claim terms. The Court conducted a Markman hearing 

on claim construction 28 August 2020. See Order, ECF No. 149. 

B. Technology Overview 

According to the '159 patent, technology utilized prior to the invention of the disclosed 

motion-tracking systems did not utilize “inertial trackers . . . in applications which require 

tracking motion relative to a moving platform . . . .” '159 Patent at Abstract. To fill this 

perceived gap in the application of such technology, the '159 patent set out to “enable[] the use 

of inertial head-tracking systems on-board moving platforms by computing the motion of a 

‘tracking’ Inertial Measurement Unit (IMU) mounted on the HMD [head mounted display] 

relative to a ‘reference’ IMU rigidly attached to the moving platform.” Id. As the Court noted in 

its previous 6 April Order: 

Conventional motion tracking systems use an inertial sensor mounted on the 

tracked object and another mounted on the moving reference frame, such as the 

aircraft. Inertial sensors measure linear accelerations or rotation rates with respect 

to the reference frame of the earth. The linear accelerations or rotation rates are 

integrated to reveal the orientation of the object relative to the earth. The difference 

between these values reveals the relative orientation or position of the respective 

sensors. 

Thales Disc. Order at 41 (internal quotation marks omitted). 

The Federal Circuit, when reviewing this court’s previous decision invalidating the 

claims of the '159 patent pursuant to 35 U.S.C. § 101, further noted that “[w]hen mounted on a 

moving object, inertial sensors can calculate the position, orientation, and velocity of the object 

in 3-dimensional space, based on a specified starting point, without the need for any other 

external information.” Thales Visionix Inc. v. United States, 850 F.3d 1343, 1345 (Fed. Cir. 

2017). “Because small errors in the measurement of acceleration and angular velocity translate 

to large errors in position over time, inertial systems generally include at least one other type of 

sensor, such as an optical or magnetic sensor, to intermittently correct these errors that 

compound over time.” Id. 

The '159 patent proposed an alternative inertial tracking system to track an object relative 

to a moving reference frame, as opposed to relative to the ground. 
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The helmet-mounted display system (“HMDS”) of the '159 patent is synchronized 

with changes in the helmet’s orientation based upon the orientation of the tracked 

object relative to the moving reference frame, rather than relative to the earth. [T]he 

system determines a ‘relative’ angular rate or acceleration signal from the sensors, 

and then integrates that relative signal to determine the orientation or position of 

the helmet relative to the aircraft. For purposes of differentiating the two methods 

of motion tracking, the conventional systems are hereinafter referred to as the “old 

method,” while the systems of the '159 patent are referred to as the “new method.”

Thales Disc. Order at 41 (internal quotation marks and citations omitted). The Federal Circuit 

noted this “new method” of the '159 patent utilizes “the platform (e.g., vehicle) inertial sensors 

[to] directly measure the gravitational field in the platform frame.” Thales, 850 F.3d at 1345. As 

a result, “[t]he object (e.g., helmet) inertial sensors then calculate position information relative to 

the frame of the moving platform.” Id. This change in the “reference frame” allows for the 

tracking of “the position and orientation of the object within the moving platform without input 

from a vehicle altitude reference system or calculating orientation or position of the moving 

platform itself.” Id. In view of these differences between the “old method” and the “new 

method,” the Federal Circuit noted “multiple advantages of the disclosed system over the prior 

art.” Id. These advantages included: “increase[d] . . . accuracy with which inertial sensors 

measure the tracked object on the moving frame;” the ability to “operate independently, without 

requiring other hardware on the moving platform that determine the orientation or position of the 

moving platform itself;” and simpler installation as “the whole system is installed on the inside 

of the moving platform.” Id. 

During the inter partes review (“IPR”), the Patent Trial and Appeal Board (“PTAB”) 

analyzed the '159 patent in view of one prior art reference in particular, McFarlane. Thales Disc. 

Order at 42. As the Court noted in the 6 April Order, “[i]n differentiating the ‘new method’ of 

the '159 patent from the ‘old method’ disclosed in the prior art, plaintiff’s expert witness 

provided the following explanation of the two-step process which the ‘new method’ follows: 

‘the raw signal data from the inertial sensors . . . is used to determine the relative angular rate 

signal;’ and ‘[t]hat relative angular rate signal . . . is then used to calculate the relative 

orientation.’” Id. at 44 (quoting Elbit Systems of Am., LLC v. Thales Visionix, Inc., 881 F.3d 

1354, 1358 (Fed. Cir. 2018)). Plaintiff prepared the following figure in its responsive claim 

construction brief based on representations previously made by their expert, Dr. Welch. The 

Court finds this figure helpful in illustrating the “new method,” or “two-step method,” used by 

the '159 patent to calculate the relative orientation of a moving object: 

New Method 
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Old Method

Pl.’s Resp. Cl. Constr. Br. at 3. In the above figure, “MO” is used to indicate the moving object, 

while “MRF” is used to indicate the moving reference frame. Id. at 2. Both the old and new 

methods utilize these sensors to transmit angular rate data (“AR”). The “new method,” however, 

then uses the angular rate to calculate a relative angular rate, or “ARREL.” Id. The relative 

orientation of the object (“OREL”) is then calculated by integrating the relative angular rate. Id. 

The “old method” does not calculate a relative angular rate. Instead, the angular rate data is used 

to perform “separate orientation calculations made with respect to the ground (OMO, OMRF).” 

Id. at 3. As illustrated by the “old method” above, the OREL is then calculated using these 

ground-based orientation calculations. Id.

C. Overview of Claims 

Following the PTAB proceedings, only eight asserted claims remain in this case: claims 

3–5, 13, 24–26, and 34. Defs.’ Op. Cl. Constr. Br. at 5. All of the remaining asserted claims are 

dependent claims. See '159 Patent at 11:49–14:18. Claims 3–5 and 13 depend from independent 

claim 1; claims 24–26 and 34 depend from independent claim 22. See id. Each of the remaining 

asserted claims requires integration (or double integration) of either a relative angular rate signal

or a relative linear acceleration signal. The disputed claim terms appear in the claims as follows: 

Claim Term Applicable Claims 

an element 3, 13

a relative angular rate signal determined from 

the angular rate signals measured by the first 

and second inertial sensors 

3, 24

a relative linear acceleration signal computed 

from the linear accelerometer signals 

measured by the first and second inertial 

sensors 

13, 34
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Accordingly, the Court finds claims 3 and 13 most useful for illustrating the disputed 

claims. Claim 3 depends from claim 2, which in turn depends from independent claim 1. Claim 

13 depends from claim 12, which in turn depends from claim 11. Claim 11 similarly traces its 

dependence back to claims 1 and 2. A full understanding of the scope of claims 3 and 13 

therefore requires an understanding of each of claims 1, 2, 11, and 12. Claims 1–3 and 11–13

are reproduced below, with emphasis on each of the disputed claim terms: 

1. A system for tracking the motion of an object relative to a moving reference 

frame, comprising: 

a first inertial sensor mounted on the tracked object; 

a second inertial sensor mounted on the moving reference frame; and 

an element adapted to receive signals from said first and second inertial 

sensors and configured to determine an orientation of the object relative to 

the moving reference frame based on the signals received from the first and 

second inertial sensors. 

2. The system of claim 1 in which the first and second inertial sensors each 

comprises three angular inertial sensors selected from the set of angular 

accelerometers, angular rate sensors, and angular position gyroscopes. 

3. The system of claim 2, in which the angular inertial sensors comprise angular 

rate sensors, and the orientation of the object relative to the moving reference frame 

is determined by integrating a relative angular rate signal determined from the 

angular rate signals measured by the first and second inertial sensors. 

11. The system of claim 2, in which the first and second inertial sensors each further 

comprises three linear accelerometers. 

12. The system of claim 11, further comprising an element for calculating the 

position of the object relative to the moving reference frame. 

13. The system of claim 12, in which the calculating element double-integrates a 

relative linear acceleration signal computed from the linear accelerometer signals 

measured by the first and second inertial sensors. 

'159 Patent col. 11:49–12:2, 12:38–47 (emphasis added). 

II. Construction of Disputed Claim Terms 

A. Applicable Law

1. Construction of Claim Terms 
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“[T]he interpretation and construction of patents claims, which define the scope of the 

patentee’s rights under the patent, is a matter of law exclusively for the court.” Markman v. 

Westview Instruments, Inc., 52 F.3d 967, 970–71 (Fed. Cir. 1995). “To construe a claim term, 

the trial court must determine the meaning of any disputed words from the perspective of one of 

ordinary skill in the pertinent art at the time of filing.” Chamberlain Grp. v. Lear Corp., 516 

F.3d 1331, 1335 (Fed. Cir. 2008). “[T]he words of a claim ‘are generally given their ordinary 

and customary meaning,’” which “is the meaning that the term would have to a person of 

ordinary skill in the art in question at the time of the invention, i.e., as of the effective filing date 

of the patent application.’” Phillips v. AWH Corp., 415 F.3d 1303, 1312–13 (Fed. Cir. 2005) 

(citing Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)). “There are 

only two exceptions to this general rule: (1) when a patentee sets out a definition and acts as his 

own lexicographer, or (2) when the patentee disavows the full scope of a claim term either in the 

specification or during prosecution.” Thorner v. Sony Comput. Entm’t Am. LLC, 669 F.3d 1362, 

1365 (Fed. Cir. 2012). 

The analysis of any disputed claim terms begins with the intrinsic evidence of record, as 

“intrinsic evidence is the most significant source of the legally operative meaning of disputed 

claim language.” Vitronics, 90 F.3d at 1582. Additional claims, whether asserted or not, “can 

also be valuable sources of enlightenment as to the meaning of a claim term.” Phillips, 415 F.3d 

at 1314. This includes consistent use throughout the patent, differences amongst particular 

terms, and various limitations added throughout the dependent claims. Id. at 1314–15. The 

claims do not stand on their own; “they are part of ‘a fully integrated written instrument,’ 

consisting principally of a specification that concludes with the claims.” Id. at 1315 (quoting 

Markman, 52 F.3d at 978). The claims are therefore “read in view of the specification.” 

Markman, 52 F.3d at 979. It is important that limitations from preferred embodiments are not 

read “into the claims absent a clear indication in the intrinsic record that the patentee intended 

the claims to be so limited.” Liebel-Flarsheim v. Medrad, Inc., 358 F.3d 898, 913 (Fed. Cir. 

2004). 

The prosecution history may serve as an additional source of intrinsic evidence. 

Markman, 52 F.3d at 980. The prosecution history “consists of the complete record of the 

proceedings before the [United States Patent and Trademark Office (“USPTO”)] and includes the 

prior art cited during the examination of the patent.” Phillips, 415 F.3d at 1317. The 

prosecution history “represents an ongoing negotiation between the [US]PTO and the applicant, 

rather than the final product of that negotiation.” Id. This results in the prosecution history often 

“lack[ing] the clarity of the specification,” making it “less useful for claim construction 

purposes.” Id. After considering all intrinsic evidence of record, the court has discretion to 

consider sources of extrinsic evidence, such as dictionaries, treatises, and expert and inventor 

testimony, if the court “deems it helpful in determining ‘the true meaning of language used in the 

patent claims.’” Id. at 1317–18. While sometimes helpful, extrinsic evidence is “less significant 

than the intrinsic record in determining the legally operative meaning of claim language.” Id. at 

1317 (quoting C.R. Bard, Inc. v. U.S. Surgical Corp., 388 F.3d 858, 862 (Fed Cir. 2004) (internal 

quotation marks and citations omitted)).

2. Prosecution Disclaimer 
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“Prosecution disclaimer ‘preclud[es] patentees from recapturing through claim 

interpretation specific meanings disclaimed during prosecution.’” Aylus Networks, Inc. v. Apple 

Inc., 856 F.3d 1353, 1359 (Fed. Cir. 2017) (quoting Omega Eng’g, Inc. v. Raytek Corp., 334 

F.3d 1314, 1323 (Fed. Cir. 2003)). Federal Circuit caselaw “requires that the alleged disavowing 

actions or statements made during prosecution be both clear and unmistakable” in order to apply 

the principles of prosecution disclaimer. Id. (quoting Omega Eng’g, 334 F.3d at 1325–26). 

“[W]hen the patentee unequivocally and unambiguously disavows a certain meaning to obtain a 

patent, the doctrine of prosecution history disclaimer narrows the meaning of the claim 

consistent with the scope of the claim surrendered.” Biogen Idec, Inc. v. GlaxoSmithKline LLC, 

713 F.3d 1090, 1095 (Fed. Cir. 2013). “Where the alleged disavowal is ambiguous, or even 

‘amenable to multiple reasonable interpretations,’ [the Federal Circuit has] declined to find 

prosecution disclaimer.” Avid Tech., Inc. v. Harmonic, Inc., 812 F.3d 1040, 1045 (Fed. Cir. 

2016) (quoting Cordis Corp. v. Medtronic AVE, Inc., 339 F.3d 1352, 1359 (Fed. Cir. 2003)). 

The Federal Circuit recognizes disclaimer to “include[] all express representations made 

by or on behalf of the applicant to the examiner to induce a patent grant.” Standard Oil Co. v. 

Am. Cyanamid Co., 774 F.2d 448, 452 (Fed. Cir. 1985). Disclaimers may thus present 

themselves through either amendment to the claims, or arguments presented by the patentee. 

Aylus Networks, 856 F.3d at 1359. “Though this doctrine arose in the context of pre-issuance 

prosecution, [the Federal Circuit has] applied the doctrine in other post-issuance proceedings 

before the [USPTO].” Id. at 1360. In extending this doctrine to inter partes review (“IPR”) 

proceedings before the Patent Trial and Appeal Board (“PTAB”), the Federal Circuit noted it 

would “ensure that claims are not argued one way in order to maintain their patentability and in a 

different way against accused infringers.” Id. Applying prosecution disclaimer to IPR 

proceedings thus “‘promote[s] the public notice function of the intrinsic evidence and protect[s] 

the public’s reliance on definitive statements made during’ IPR proceedings.” Id. (quoting 

Omega Eng’g, 334 F.3d at 1324). 

B. Terms Resolved by the Parties 

In the parties’ first joint claim construction chart, eleven claim terms were identified as 

being disputed. See Joint Claim Construction Chart, ECF No. 154. After a meet and confer, the 

parties filed an amended joint claim construction chart. See Am. Joint Claim Construction Chart, 

ECF No. 158. Of the eleven claim terms originally disputed, the parties were able to reach an 

agreement amongst themselves as to a construction for five of the disputed terms, as shown by 

the chart below:

Claim Term Agreed-Upon Construction 

based on the signals received from the first 

and second inertial sensors

based on signals from two inertial sensors 

plain and ordinary meaning 

angular rate sensors plain and ordinary meaning

a non-inertial measuring subsystem plain and ordinary meaning
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for correcting drift to attempt to reduce cumulative measurement 

errors 

double-integrates 

double-integrating 

plain and ordinary meaning

The parties further combined a series of the initially disputed terms, leaving just three 

terms requiring construction by the Court. 

III. Disputed Claim Term #1: “an element” 

Plaintiff’s Proposed Construction Defendants’ Proposed Construction 

one or more associated processing units and 

electronic components

plain and ordinary meaning, wherein the plain 

and ordinary meaning is a one or more 

components involved in the inertial 

calculations

A. Parties Arguments 

Defendants argue the proper construction of “an element” is straightforward, as it is a 

generic term readily understood by a person having ordinary skill in the art (“PHOSITA” or 

“POSITA”). Defs.’ Op. Cl. Constr. Br. at 23. Defendants further argue, to the extent this term 

requires construction, the court should adopt the plain and ordinary meaning, which defendants 

identify as “a component used in inertial calculations.” Id. at 25. Plaintiff argues the proper 

construction for “an element” must include the term “associated,” as this more properly 

illustrates the relationship between the processing units and the inertial computation. Pl.’s Resp. 

C. Constr. Br. at 23. Plaintiff also argues for replacing the term “component” from defendants 

proposed construction with “processing units and electronic components,” noting these terms act 

to narrow the scope of the claims to particular types of “components.” Pl.’s Reply Cl. Constr. 

Br. at 14–15. 

Plaintiff further notes use of the indefinite article “a” or “an” carries the meaning of “one 

or more.” Pl.’s Op. Cl. Constr. Br. at 5. Plaintiff thus advocates for the inclusion of “one or 

more” to ensure this is reflected in the Court’s construction. Id. at 6. Although defendants’ 

proposed construction does not similarly contain the phrase “one or more,” defendants do not 

oppose the inclusion of this phrase in the construction of “an element.” See, e.g., Defs.’ Resp. 

Cl. Constr. Br. at 20 (“Defendants have not made any proposals or arguments regarding how 

many processors ‘an element’ may include, and in particular Defendants have not limited it to a 

single processor as Plaintiff argues.”); Tr. at 16:3–5 (defendants’ counsel responding to the 

Court’s question whether there was “any dispute related to ‘an element’ potentially covering 

plurality:” “No, Your Honor.”); id. at 18:15–17 (defendants’ counsel stating: “I think as we’ve 

already agreed today, Defendants are not disputing that it could be one or more components.”). 

The Court provided the parties with the following preliminary construction prior to the 

Markman hearing: “an element” is construed according to its “plain and ordinary meaning.” Tr. 

at 8:13–15. During the Markman hearing, defendants’ counsel clarified the slight disagreement 
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between the parties proposed constructions: “I think that the issue arises whether or not the 

element can do additional processing that is not related to the inertial calculations. And so our 

concern is that the Plaintiff’s construction does encompass more than what the claims describe.” 

Id. at 18:18–22. In response, plaintiff’s counsel further clarified just how close the parties’

respective positions are: “[W]e feel like plain and ordinary meaning is okay as long as these 

other things that are going on are not excluded. . . . I think there may be components involved in 

the inertial calculations that aren’t claimed because this is such a complex thing.” Id. at 35:3–5, 

35:17–19. 

While attempting to reconcile this slight difference in proposed constructions, both 

parties agreed the issue does not raise any concerns regarding the Federal Circuit’s direction in 

O2 Micro International Ltd. v. Beyond Innovation Tech. Co., Ltd., 521 F.3d 1351, 1361 (Fed. 

Cir. 2008): “A determination that a claim term . . . has the ‘plain and ordinary meaning’ may be 

inadequate when a term has more than one ‘ordinary’ meaning or when reliance on a term’s 

‘ordinary’ meaning does not resolve the parties’ dispute.” In their briefing, defendants argue the 

term “an element” “does not require construction; as such the O2 Micro holding does not apply 

here.” Defs.’ Op. Cl. Constr. Br. at 24. Defendants’ counsel further represented at the Markman

hearing they “don’t really see this as an O2 Micro issue,” further noting “[w]e don’t think that’s 

an O2 Micro issue on element. We think that if there’s ever a dispute, the Court as a fact-finder 

could use its own fact-finding skills to determine whether what they point to is an element or 

not.” Tr. at 30:10–11, 32:11–15. Plaintiff’s counsel further noted they “prefer there not be an 

O2 Micro issue.” Id. at 34:12–13. As the Federal Circuit has stated, “a sound claim construction 

need not always purge every shred of ambiguity. The resolution of some line-drawing problems 

. . . is properly left to the trier of fact.” Acumed LLC v. Stryker Corp., 483 F.3d 800, 806 (Fed. 

Cir. 2007); see also PPG Indus. v. Guardian Indus. Corp., 156 F.3d 1351, 1355 (Fed. Cir. 1998) 

(“[A]fter the court has defined the claim with whatever specificity and precision is warranted by 

the language of the claim and the evidence bearing on the proper construction, the task of 

determining whether the construed claim reads on the accused product is for the finder of fact.”). 

B. Plain and Ordinary Meaning 

The Court begins by giving claim terms “their ordinary and customary meaning” in view 

of the intrinsic record. Phillips, 415 F.3d at 1312–13. The specification of the '159 patent only 

uses the term “element” three times, each in the “Summary of the Invention” section.

1

 See 

generally '159 Patent. First, the specification refers to “an element coupled to the first and 

second inertial sensors.” Id. at 1:58–59. The second reference to “an element” states “[a]n 

element may be included for calculating the position of the object relative to the moving 

reference frame.” Id. at 2:31–33. The third and final reference to “an element” in the 

specification notes “[t]he calculating element may double-integrate the relative linear 

acceleration signal computed from the linear accelerometer signals measured by the first and 

second inertial sensors.” Id. at 2:33–36. 

1 The term “elements” also appears once in the specification. This term, however, is used in a different context 

relating to variables contained in a “skew-symmetric matrix formed from the elements” and thus does not aid the 

Court in construing the claim term at issue. '159 Patent at 3:51–52. 
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As the parties agreed during the Markman hearing, the plain and ordinary meaning, in 

view of the intrinsic record, should govern the construction of “an element.” See Tr. at 18:12–15 

(defendants’ counsel stating “[d]efendants agree that plain and ordinary meaning is sufficient and 

the term ‘an element’ does not need additional construction”); id. at 35:3–5 (plaintiff’s counsel 

noting “we feel like plain and ordinary meaning is okay as long as these other things that are 

going on are not excluded”). The only disagreement remaining between the parties is whether

“an element” is broad enough to encompass anything “associated” with an aircraft generally, or 

must instead be “related to the inertial calculations.” Id. at 18:20; see also Tr. at 31:9–12, 31:23–

24 (defendants’ counsel noting their “major concern is just associated, the term–the reason why 

we think plain and ordinary is better than using the word associated is if something in the F-35, 

in the jet, . . . [we] would say that’s not within the plain and ordinary meaning of an element”). 

In an effort to illustrate the breadth of “an element,” plaintiff consistently referred back to 

Figure 4 of the '159 patent. See, e.g., Tr. at 16:20–17:4 (“Figure 4 says that each part of the 

processing element . . . has different parts. . . . However, Figure 4 says nothing about these being 

the only elements. And that makes sense because this is a complicated inertial tracking device, 

and there are going to be other things in here like buffers and things like that that aren’t 

shown.”). Defendants dispute the applicability of Figure 4 to the remaining claims at issue, 

noting “it is not clear which of the claims Figure 4 is related to.” Id. at 18:24–25. Defendants 

further argue “Figure 4 does not depict any other processing units that are performing processing 

functions not related to the inertial sensor data.” Id. at 24:23–25:1. Thus, defendants position is 

best summarized as follows: “in looking to the claims, the claims say that what the element 

receives is data from the inertial sensors and it performs the necessary calculations within the 

elements. . . . [Plaintiff] only describe[s] the element performing calculations related to the 

inertial sensor data.” Id. at 25:4–10. 

Further questioning by the Court, however, revealed plaintiff’s position is no different 

from defendants. When specifically asked whether the use of the term “associated” in plaintiff’s 

proposed construction could encompass “component[s] not directly involved with the inertial 

calculations,” plaintiff’s counsel responded:

I’m not sure that would make a difference. I think there may be components 

involved in the inertial calculations that aren’t claimed because this is such a 

complex thing. And the claims are saying, look, we came up with this new thing, 

this relative angular rate that was not used before, and we’ve got a claim that shows 

you how to take the angular rate data from the sensors and send it to the element. 

But then it’s not specific about how—the claim is not specific about how the 

elements calculate the relative angular rate. . . . [T]here could be other things in the 

system. It’s not that you write this claim and then you’re stuck only with these 

things. 

Id. at 35:16–36:11 (emphasis added). Plaintiff is thus concerned whether defendants’ proposed 

construction will narrow the construction of “an element” to only that which is explicitly 

claimed, and nothing else. “An element,” as used in claim 1, is part of a system claim utilizing 

the open-ended transition “comprising.” '159 Patent at col. 11:49–55. “The transition 

‘comprising’ in a method claim indicates that the claim is open-ended and allows for additional 
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steps.” Invitrogen Corp. v. Biocrest Mfg., L.P., 327 F.3d 1364, 1368 (Fed. Cir. 2003). To the 

extent plaintiff is concerned with the plain and ordinary meaning of “an element” operating to 

exclude other components involved in the inertial calculations as a result of not being explicitly 

claimed, such a construction would be contrary to established precedent. Further, it is not yet 

before the Court whether defendants accused system satisfies this definition of an element. See 

PPG Indus., 156 F.3d at 1355 (“[A]fter the court has defined the claim with whatever specificity 

and precision is warranted by the language of the claim and the evidence bearing on the proper 

construction, the task of determining whether the construed claim reads on the accused product is 

for the finder of fact.”). 

C. Court’s Construction 

As the parties agreed during the Markman hearing, “an element” shall be given its plain 

and ordinary meaning in view of the intrinsic record. 

Plaintiff’s Proposed Construction Defendants’ Proposed Construction (with 

edits) 

one or more associated processing units and 

electronic components

plain and ordinary meaning, wherein the 

plain and ordinary meaning is a one or more 

components involved in the inertial 

calculations

Court’s Construction

Plain and ordinary meaning

IV. Disputed Claim Term #2: “a relative angular rate signal determined from the 

angular rate signals measured by the first and second inertial sensors”

Plaintiff’s Proposed Construction Defendants’ Proposed Construction 

signal data representing the rate that the 

tracked object is rotating in the moving 

reference frame determined using signal data 

representing the angular rate of objects 

measured by the first and second inertial 

sensors

a signal representing the rate at which the 

tracked object is rotating relative to the 

moving reference frame that is computed 

directly from the raw signals measured by the 

first and second angular rate sensors

A. Parties Arguments 

Plaintiff argues using the term “in” to describe the relationship between the tracked 

object and the moving reference frame is “simpler” than defendants’ proposal: “rotating relative 

to the moving reference frame.” Pl.’s Op. Cl. Constr. Br. at 7. Plaintiff next takes issue with 

defendants proposed use of “angular rate sensors,” arguing this limitation is too restrictive and 

should be replaced with the broader phrase “inertial sensors.” Id. at 8. According to plaintiff, 

however, neither of these disagreements are considered “substantive.” Id. 
- 13 -

The first “substantive” disagreement plaintiff identifies is that “signal” should be 

construed as “signal data” based on both the specification and dictionary definitions. Id. at 9. 

Lastly, plaintiff accuses defendants of “insert[ing] a further limitation into the claim language.” 

Id. at 10. According to plaintiff, defendants’ “additional limitations restrict how a relative rate 

signal is ‘determined,’ which according to [defendants] ‘is computed directly’ and from ‘raw 

signals.’” Id. Plaintiff asserts “the claim language explicitly does not include limitations on how 

the relative angular rate signal is determined.” Id.

Defendants argue their proposed construction “flows from [plaintiff’s] many statements 

to the Patent Office regarding the scope of its claims during the IPR proceeding, which are part 

of the intrinsic record and limit the claims under the prosecution disclaimer doctrine.” Defs.’ 

Op. Cl. Constr. Br. at 7. Even if the Court declines to apply the doctrine of prosecution 

disclaimer, defendants argue their proposed construction “accords with the patent specification” 

as it “defines the relative angular rate signal with an equation” specifying “the relative angular 

rate signal is calculated directly from the raw signals form the inertial sensors.” Id. at 17–18. As 

the equation provided in the specification is the only disclosed embodiment of plaintiff’s “novel 

concept introduced by the patent,” defendants argue the only possible construction for this term 

is one that accords with the disclosed embodiment, as “this is . . . how a skilled artisan would 

understand the term.” Id. at 18–19. Defendants further argue plaintiff is “judicially estopped 

from arguing that a ‘relative angular rate signal’ does not have to be computed from the inertial 

sensors’ ‘raw signals’” based on “representations to the Federal Circuit in its Section 101 

appeal.” Id. at 19–20. 

The Court provided the parties with the following preliminary construction prior to the 

Markman hearing: “signal data representing the rate at which the tracked object is rotating 

relative to the moving reference frame, determined from signal data received directly from the 

first and second angular rate sensors.” Tr. at 8:16–23. As the parties disagree as to various 

smaller terms within the context of the claim term at large, the Court addresses each of the 

individual claim terms individually (though within the overall larger context of the entire claim 

term itself). 

B. Individual Claim Terms Within Broader Claim Term 

1. “signal” vs. “signal data” 

Plaintiff proposes using the phrase “signal data” in place of the claim term “signal,” as it 

clarifies the information being transmitted is not “the electromagnetic carrier wave or impulse 

itself rather than the data carried on that wave or impulse.” Pl.’s Op. Cl. Constr. Br. at 8–9. The 

Court begins by giving claim terms “their ordinary and customary meaning” in view of the 

intrinsic record. Phillips, 415 F.3d at 1312–13. A reading of the claims themselves shows the 

claims consistently refer to only a “signal.” See generally '159 patent. The specification of the

'159 does not utilize the phrase “signal data.” See id. The specification does, however, refer to 

both “signals” and “data” seemingly interchangeably. For example, the specification refers to 

signals in the following instances: “signals from the first and second inertial sensors;” “signals 

from the first inertial sensor;” and “signals from the second inertial sensor.” Id. at col. 1–2. The 

specification further refers to “data” as: “data available from the two IMUs [inertial 
- 14 -

measurements units];” and “[t]he processor unit gathers the data from the various sensors.” Id. at 

col. 8:17, 8:66–67. Each of these uses throughout the specification references either the output 

of the sensors or the input of the processor unit. 

The phrase “signal data” is further consistent with the Federal Circuit’s previous

characterization in this case. In Elbit Systems, the Federal Circuit adopted plaintiff’s expert’s

definition of the “new method,” wherein the term “signal data” was used to characterize the 

information being transmitted from the inertial sensors. Elbit Systems, 881 F.3d at 1358. As the 

Federal Circuit noted, the “signal data” is then “used to determine the relative angular rate 

signal.” Id. Such a determination involves various “calculations required to determine relative 

orientation.” Id. As set forth in detail in the specification of the '159 patent, these calculations 

involve a series of equations. The '159 patent contemplates the use of numerical values coming 

from the inertial sensors and being sent to the processor unit for further computation. See ‘159 

patent at Fig. 4. As the term “signal” when used in isolation could be potentially ambiguous as 

to whether it references the numerical value itself, or rather the carrier wave responsible for 

transmitting the numerical value, the Court finds clarifying this term with the phrase “signal 

data” removes any ambiguity. 

“Signal data” is further supported by the extrinsic evidence presented by plaintiff. The 

Court has discretion to evaluate any extrinsic evidence presented by the parties. Phillips, 415 

F.3d at 1317. Plaintiff presents two sets of dictionary definitions for “signal.” Pl.’s Op. Cl. 

Constr. Br. at 9–10. These definitions are provided by plaintiff to support its position the term 

“signal” is used in the ‘159 specification to describe “the data itself that provides the angular rate 

of the object being tracked, and that the specification teaches is operated on.” Id. at 9. Each of 

the definitions presented by plaintiff provides alternative definitions for signal: either a means 

for transmitting a sound, image, or message, or the sound, image or message itself. See 

American Heritage College Dictionary, 4th ed. 1290 (2004) (“[a]n impulse or a fluctuating 

electric quantity, such as voltage, whose variations represent coded information;” “[t]he sound, 

image, or message transmitted or received in telegraphy, telephony, radio, television, or radar”); 

Merriam-Webster Online Dictionary (“the sound or image conveyed in telegraphy, telephony, 

radio, radar, or television;” “a detectable physical quantity or impulse (such as a voltage, current, 

or magnetic field strength) by which messages or information can be transmitted.”). In analyzing 

the ‘159 patent, the Federal Circuit explained “the raw signal data from the inertial sensors . . . is 

used to determine the relative angular rate signal . . . [and] [t]hat relative angular rate signal . . . 

is then used to calculate the relative orientation.” Elbit Systems, 881 F.3d at 1358 (quoting J.A. 

2112). The “signal” of the asserted claims undergoes subsequent computations, in accordance 

with both the specification and the Federal Circuit’s previous characterization of the claim 

language. 

Consistent with the Court’s preliminary construction provided to the parties prior to the 

Markman hearing, defendants’ counsel clarified that with respect to this individual term within 

the larger disputed claim term, while “not waiving” the arguments presented in its briefing, it 

was “not [at the Markman hearing] fighting anymore on ‘signal data.’” Tr. at 44:9–13. Plaintiff 

went a step further than defendants, representing they “are okay with the Court’s proposed 

construction. We can accept it.” Id. at 68:6–7. Thus, consistent with the parties’ representations 
- 15 -

during the Markman hearing and the discussion set forth here, the Court construes “signal” to 

mean “signal data.” 

2. “rotating in the moving reference frame” vs. “rotating relative to the 

moving reference frame” 

Plaintiff characterizes the parties proposed constructions of this second smaller claim 

term as exhibiting “no significant difference,” but claims its proposed construction of the phrase 

better “reflects that fact that the tracked object is moving ‘in’ the moving reference frame.” Pl.’s 

Op. Cl. Constr. Br. at 7. Plaintiff, however, does not present any evidence in the specification or 

otherwise indicating what it means to rotate “in the moving reference frame.” The claim 

language describes the “orientation of the object relative to the moving reference frame.” '159 

Patent at col. 11:65–66. Each of the respective sensors are placed on the tracked object and on

the moving reference frame. Id. at col. 11:52, 53–54. Neither the claims, or the specification,

detail the tracked object to be in the moving reference frame. Plaintiff’s proposed construction is 

therefore at odds with the claim language itself. As each of the inertial sensors measures a value, 

and the respective values are used to determine the relative orientation of the object, it follows 

that describing the rotation of the tracked object is done so “relative to the moving reference 

frame.” Defs.’ Resp. Cl. Constr. Br. at 15. 

While defendants’ counsel did not explicitly address this argument during the Markman 

hearing, they did note “we really think the dispute can be narrowed to the issue of the word 

‘directly.’” Tr. at 44:13–15. Defendant’s expressed at the Markman hearing they are “not here 

today fighting anymore on ‘signal data’” or contest “most of the Court’s construction” of the 

relevant claim term except the desired addition of the word “directly” in the claim term. Id. at 

44:12–20. Accordingly, the claim language itself dictates the rate at which the tracked object is 

rotating “relative to the moving reference frame;” the tracked object does not “rotate in the 

moving reference frame.” 

3. “determined using signal data representing the angular rate of 

objects” vs. “computed directly from the raw signals” 

Perhaps the parties’ most significant disagreement involves the construction of 

“determined from the angular rate signals.” Plaintiff maintains defendants’ proposed 

construction imparts an additional limitation into the claims, restricting how a relative angular 

rate signal is determined. Pl.’s Op. Cl. Constr. Br. at 10. Defendants do not dispute they seek to 

impart such an additional limitation, but rather argue the additional imitation is required based on 

various legal doctrines requiring the importation of such a limitation into the claim language. 

Defs.’ Op. Cl. Constr. Br. at 8. As defendants’ counsel noted during the Markman hearing, “we 

really think the dispute can be narrowed to the issue of the word ‘directly.’” Tr. at 44:13–15. 

a. Prosecution History Disclaimer 

Defendants first, and primary, theory for justifying the inclusion of the additional claim 

term is prosecution history disclaimer. As the Federal Circuit has clarified, prosecution history 

disclaimer is applicable to IPR proceedings at the PTAB and can be used to restrict the scope of 
- 16 -

claims based on a patentee’s statements made during such proceedings. Aylus Networks, 856 

F.3d at 1358–59. Defendants identify a series of statements made by both plaintiff and 

plaintiff’s expert during the IPR proceeding which purportedly limited the scope of claim 3. For 

example, defendants identify the following language from the previous proceedings: “Claims 3 

and 24 of the '159 Patent are limited to systems or methods wherein raw signals measured by the 

first and second angular rate sensors are used to determine a relative angular rate signal.” Defs.’ 

Op. Cl. Constr. Br. at 9 (quoting ECF No. 107-12 at 6) (emphasis in original). Defendants next 

highlight a quote from plaintiff’s expert related to what the “claims require.” “[T]he inventors of 

the '159 Patent teach (and the claims require) processing raw signals, i.e., directly from sensors.” 

Id. at 9 (quoting ECF No. 121-1 ¶ 52) (emphasis in original). 

Defendants continuously rely on plaintiff’s expert’s statements in support of their 

proposed claim construction. “[I]nventions claimed in the '159 Patent directly use signals from 

the sensors (i.e., raw signals) on both the moving object and moving reference frame to 

determine relative signals which are used to determine relative orientation.” Id. at 10 (quoting 

ECF No. 107-12 at 3) (emphasis in original). Regarding the alleged “new method” of the system 

of the '159 patent, defendants point to the following quote from plaintiff’s expert: “In contrast 

[to the old way], . . . the ‘new way’ recited in claims 3 and 24 uses raw signal data to determine 

a relative angular rate signal, which is used to determine relative orientation.” Id. at 10 (quoting 

ECF No. 107-12 at 33) (emphasis in original). Defendants then move on to statements from 

plaintiff’s expert specifically directed to alleged improvements over the prior art during the 

previous proceedings: “McFarlane does not teach using raw signals directly from the gyros 

(inertial sensors) to compute relative orientation.” Id. at 11 (quoting ECF No. 107-12 at 29)

(emphasis in original); see also Id. at 11 (quoting ECF No. 121-1 ¶ 70) (“[A] POSITA would 

understand that McFarlane explicitly teaches the use of already processed azimuth and elevation 

signals (FAZ and FEL). Further, a POSITA would understand that AZ/EL and FAZ/FEL are not 

raw signals obtained directly from gyros (inertial sensors) mounted on the helmet or vehicle, 

respectively.”) (emphasis in original); Id. at 11 (quoting ECF No. 107-12 at 30) (“Velger does 

not disclose using raw signals from the disclosed accelerometers or gyros to determine relative 

orientation and position.”) (emphasis in original). 

Although the IPR proceeding did not directly involve a dispute as to the current claim 

term, it did involve significant review of the '159 patent and associated prior art. In particular, 

the PTAB looked at whether “the method of integrating the ‘relative angular rate signal’ taught 

in claim 3 of the '159 patent would have been obvious to a [person having ordinary skill in the 

art].” Elbit Systems, 881 F.3d at 1357. In attempting to distinguish the '159 patent over the prior 

art, plaintiff’s expert distilled the system of the '159 patent down to a two-step method (the “new 

method”): “‘the raw signal data from the inertial sensors . . . is used to determine the relative 

angular rate signal;’ and ‘[t]hat relative angular rate signal . . . is then used to calculate the 

relative orientation.’” Id. at 1358. The Federal Circuit found plaintiff’s expert credible, relying 

on this characterization of the “new method” as “constitut[ing] substantial evidence showing that 

the prior art does not teach the Asserted Claims’ ‘relative angular rate signal.’” Id. It was thus 

plaintiff themselves who first introduced the idea of “raw” signals into the calculus for 

determining a relative angular rate signal. Disclaimers may present themselves through either 

amendment to the claims, or arguments presented by the patentee. Aylus Networks, 856 F.3d at 
- 17 -

1359. “Prosecution disclaimer ‘preclud[es] patentees from recapturing through claim 

interpretation specific meanings disclaimed during prosecution.’” Id. 

While plaintiff initially interjected the term “raw” into the proceedings, as it does not 

appear in the specification of the '159 patent, use of this term alone does not result in a 

disclaimer of claim scope. Plaintiff must make a “clear and unmistakable” waiver of claim scope 

in order for these principles to apply. Id. (quoting Omega Eng’g, 334 F.3d at 1325–26). Further 

review of plaintiff’s statements before the PTAB show repeated use of the term “raw” in 

describing the determination of the relative angular rate signal. For example, plaintiff’s counsel 

noted “[c]laims 3 and 24 of the '159 patent are limited to systems or methods wherein raw 

signals measured by the first and second angular rate sensors are used to determine a relative 

angular rate signal.” Defs.’ Op. Cl. Constr. Br. at 9 (citing Thales PTAB brief at 6) (emphasis in 

original). Plaintiff’s expert further stated, “the inventors of the '159 patent teach (and the claims 

require) processing raw signals, i.e., directly from sensors.” Id. at 9 (citing Dr. Welch expert 

declaration at ¶ 52) (emphasis in original). Plaintiff continued to reference the use of raw 

signals: “[i]nventions claimed in the '159 Patent directly use signals from the sensors (i.e. raw 

signals) on both the moving object and moving reference frame to determine relative signals 

which are used to determine relative orientation.” Id. at 10 (citing Thales PTAB brief at 3)

(emphasis in original); see also Defs.’ Resp. Cl. Constr. Br. at 7 (citing Thales PTAB briefing at 

29) (“Because azimuth . . . and elevation . . . are measures of angles, not angular rates, a POSITA 

would readily understand that these measurements are computed by additional subsystems, and 

are not raw signals obtained directly from sensors (e.g., gyros).”); id. (“Thus, Velger discloses a 

system wherein relative orientation is determined not from raw signals from the inertial sensors, 

but rather, from further processing of that information based on a locally-level navigation 

frame.”). 

Not only did plaintiff repeatedly emphasize the need for determining the relative angular 

rate signal using raw signals, but plaintiff specifically argued this contributed to the '159 patents 

advance over the prior art: “McFarlane does not teach using raw signals directly from the gyros 

(inertial sensors) to compute relative orientation.” Defs.’ Op. Cl. Constr. Br. at 11 (citing Thales 

PTAB brief at 29) (emphasis in original). Although plaintiff argues this particular claim was not 

at issue during the IPR proceeding and thus any reference to “raw signals” at the PTAB was 

unnecessary, such arguments do not accord with established Federal Circuit caselaw. Pl.’s Op. 

Cl. Constr. Br. at 11–12. “The fact that the applicant may have given up more than was 

necessary does not render the disclaimer ambiguous. The analysis focuses on what the applicant 

said, not on whether the representation was necessary or persuasive.” Uship Int. Props., LLC v. 

United States, 714 F.3d 1311, 1315 (Fed. Cir. 2013)). 

Defendants further introduce extrinsic evidence in the form of expert testimony regarding 

what a PHOSITA would understand “raw signals” to mean in the context of the '159 patent. See 

Defs.’ Resp. Cl. Constr. Br. at 11. Defendants rely on this evidence in an attempt to show “raw 

signals” are commonly understood as “signals taken directly from the inertial sensors.” Id. 

Although plaintiff initially attempted to explain both it and its expert’s use of “raw signals” in 

the initial briefing, it found common ground with defendants’ expert’s definition of “raw” in 

their reply brief: “the claims differed [over the prior art] by requiring raw angular rate data to be 

received by the processing element directly from the sensors.” Pl.’s Op. Cl. Constr. Br. at 12–
- 18 -

13; Pl.’s Reply Cl. Constr. Br. at 2 (emphasis added); see also Pl.’s Resp. Cl. Constr. Br. at 13 

(“Thus, the specification confirms that ‘raw’ and ‘directly’ simply mean that the data is input 

from the sensor into the processing element and is ultimately used to determine a relative angular 

rate signal regardless of other processing.”). The Court agrees with this and disagrees with 

plaintiff’s earlier statements attempting to explain previous references to “raw signals” as 

nothing more than “simple examples” or “a casual term that has no precise meaning and is 

simply a cooking analogy offered to help understand the complexities of the system.” Pl.’s Op. 

Cl. Constr. Br. at 12; Pl.’s Resp. Cl. Constr. Br. at 20. During the Markman hearing, plaintiff’s 

counsel took a similar position regarding the alleged use of nothing more than a “casual” 

analogy. 

THE COURT: [I]n your initial briefing, I think you described it as explaining as a 

way of a casual cooking analogy, referring only to an embodiment, but then in your 

final reply briefing you seemed to shift gears a little bit and instead argued that raw 

only describes what is already in the claims, is that the processor uses raw signal 

data sent directly from the sensor. 

PLAINTIFF’S COUNSEL: I think that’s correct. 

Tr. at 68:24–69:7. 

As Elbit’s counsel acknowledged during the Markman hearing, the Court’s construction, 

while not using the word “raw,” adopts a meaning consistent with Elbit’s proposed use of the 

term “raw.” See Id. at 55:9–17 (responding to the Court’s questions regarding “the meaning of 

raw,” Elbit’s counsel represented “we think the Court took care of that in the preliminary 

construction.”) see also Id. at 43:9–13 (commenting on the Court’s preliminary construction, 

Elbit’s counsel stated: “We appreciate that ‘directly’ is not in the claim. So it’s our 

understanding that the Court has looked at the PTAB statements and finds there’s something 

that’s got to be done with all these statements that had to mean something.”). 

The references in the specification, coupled with both plaintiff’s and plaintiff’s expert’s 

characterizations during the IPR proceeding, support a claim limitation wherein the relative 

angular rate signal is determined from signal data received directly from the first and second 

inertial sensors. The Court thus finds plaintiff disclaimed a broader claim scope based on “clear 

and unmistakable” statements such that the scope of the claims was narrowed to only receiving 

signal data directly from the first and second angular rate sensors. Aylus Networks, 856 F.3d at 

1359. 

Yet Elbit argues the Court’s proposed construction does not go far enough. According to 

Elbit, the word “directly” must be introduced a second time into the Court’s construction, or 

alternatively reordered such that it modifies both where the signal data is received from, as well 

as how the relative angular rate signal is determined. See Tr. at 44:14–16 (“Our position is the 

[Court’s preliminary] construction needs to be clarified just slightly to show that the signals are 

not just received directly but also processed directly.”). Counsel for Elbit thus confirmed their 

“only tweak” to the Court’s preliminary construction was “to add ‘directly’ to the moving 

reference frame ‘directly determined from signal data received.’” Id. at 44: 3–7. 
- 19 -

Although the Court agrees with defendants that plaintiff disclaimed a broader scope of 

this claim term based on statements at the PTAB, the Court next turns to review defendants’ 

proposed construction to ensure it accurately represents the scope of such disclaimer. 

Defendants proposed construction states the relative angular rate signal is “computed directly

from the raw signals.” Defs.’ Op. Cl. Constr. Br. at 7 (emphasis added). Plaintiff argues, 

however, this language does not align with the actual statements made by plaintiff and plaintiff’s 

expert at the PTAB. Plaintiff’s statements were all directed to the use of “raw signals” in the 

sense that the signals are transmitted directly from the sensors to the processing unit. See, e.g.,

Defs.’ Op. Cl. Constr. Br. at 9 (citing Dr. Welch expert declaration at ¶ 52) (emphasis in 

original) (“processing raw signals, i.e., directly from sensors.”); Defs.’ Op. Cl. Constr. Br. at 10 

(citing Thales PTAB brief at 3) (emphasis added) (“directly use signals form the sensors (i.e. raw 

signals)”). 

The specification does reference sending signal data “directly” from the sensors to the 

processing unit. See, e.g., '159 Patent at col. 4:62–63 (“omegabib is available directly from the 

gyros”); id. at col. 4:66–67 (“[where] omeganin cannot be calculated, but it can be directly 

measured by gyros mounted on the moving platform”); id. at 8:14–17 (“If the reference IMU is 

mounted at the origin of the n-frame, then it directly measures fnin and omega nin, so (10) is the 

complete navigation equation, which can be integrated using just data available from the two 

IMUs.”). Defendants proposed ordering of terms, however, improperly attempts to “modify the 

computation aspect of the element rather than the signal reception aspect of the element.” Pl.’s 

Reply Cl. Constr. Br. at 4. Defendants point to nothing in the specification supporting such a 

limitation regarding determination of the relative angular rate signal, nor was defendants’ 

counsel able to identify any such support in the specification during the Markman hearing.

THE COURT: So how about in the specification, is there any detail to support this 

limitation being imparted upon the claim language? 

DEFENDANTS’ COUNSEL: [] I will say this, Your Honor. Our argument is not 

primarily based on the specification. It’s based on the disclaimer . . . . This is not 

a—this is not a you look at the spec and there’s a lexicography. We’re not pushing 

for that. It’s really what they said afterwards to save the claims. 

THE COURT: [] So your position, then, is that these arguments were clear and 

unmistakable? 

DEFENDANTS’ COUNSEL: Absolutely. 

THE COURT: Is there precedent language from the Federal Circuit that in order 

to have a construction that is limiting in this way, there must also be some support 

in the specification?

DEFENDANTS’ COUNSEL: No. I believe that is not the case law. 
- 20 -

Tr. at 59:1–21. Plaintiff’s counsel confirmed the Court’s suspicion as to whether any such 

limitation was even disclosed in the specification to begin with. As plaintiff’s counsel explained, 

“you are going to end up disclaiming in a disclaimer situation things that are in the spec. That’s 

the nature of what it is . . . . [I]t doesn’t make sense to disclaim something that was never there to 

begin with.” Tr. at 88:11–15. Although Elbit’s counsel did identify a series of cases later in the 

Markman hearing purporting to demonstrate the Federal Circuit finding a patentee disclaimed a 

limitation during prosecution which was not first disclosed in the specification, the Court could 

find no such support in any of the identified cases. Elbit’s counsel characterized this position as 

“[d]isclaimer with no need for it to be backed up by the spec, all based on what the applicant said 

in prosecution.” Tr. at 82:13–15. First, Elbit’s counsel pointed to North American Container,

Inc. v. Plastipak Packaging, Inc., 415 F.3d 1335 (Fed. Cir. 2005). Id. at 81:25–82:10. Elbit’s 

counsel directed the Court to a passage around page 1346 discussing an issue of disclaimer based 

on representations made by the patentee during prosecution of the patent in question. Id. at 

82:18–84:13. The discussion from North American Container, however, does not support Elbit’s 

position that a patentee can disclaim a limitation during prosecution or subsequent PTAB 

proceedings that was not first disclosed in the specification. Rather, North American Container 

applies prosecution disclaimer in order to exclude specific embodiments originally disclosed in 

the specification. North American Container, 415 F.3d at 1346 (“As the district court 

recognized, the fact that claims do not cover certain embodiments disclosed in the patent is 

compelled when narrowing amendments are made in order to gain allowance over prior art.”) 

(emphasis added). Second, Elbit’s counsel directed the Court to Uship Intellectual Properties, 

LLC v. United States, 714 F.3d 1311 (Fed. Cir. 2013). Tr. at 84:17–18. Elbit’s counsel 

highlighted a passage from page 1316 discussing both disclosure in the specification and the 

application of prosecution disclaimer. Id. at 84:18–21. Again, this passage does not support 

Elbit’s contention that a patentee can disclaim a limitation during prosecution or subsequent 

PTAB proceedings that was not first disclosed in the specification. In fact, Uship appears to 

suggest the very opposite. After the Federal Circuit noted it “d[id] not see the conflict about 

which [the patentee] complains,” the court went on to state: “Even if the specification had 

disclosed an embodiment [directed to the disputed limitation], prosecution disclaimer could 

result in that embodiment not being covered by the claims.” Uship Intellectual Properties, 714 

F.3d at 1316. As the Federal Circuit found the disputed limitation not disclosed in the 

specification, prosecution disclaimer was inapplicable. Id. To the extent the limitation was 

disclosed, the Federal Circuit then noted application of the doctrine of prosecution disclaimer 

“could result in that embodiment not being covered by the claims.” Id. This suggests disclosure 

of the limitation itself is a prerequisite to applying the doctrine of prosecution disclaimer in order 

to find disclaimer of such a limitation.

Alternatively, defendants attempt to invoke a series of equations recited in the 

specification to support the specification’s alleged disclosure supporting “direct processing.” 

[T]he equation at Column 5, . . . which shows the actual signal, the relative 

angular rate signal, from the omegas—one of the omegas is the moving reference, 

one of the omegas is from the person who’s being tracked, and that signal has 

no—no other inputs whatsoever. And so that is the direct processing. So the 

Court could say—could look at the one clear disclosure . . . in Column 5 of the 
- 21 -

relative angular rate signal being integrated and said that is consistent with the 

disclaimer. 

Tr. at 60:22–61:5. Defendants further elaborated on the disclosed equation in Column 5 

of the specification: 

The omega-sub-I-N is the raw signal from the moving reference frame. And 

you can see that they’ve—that’s what they’re pointing to as the so-called 

new way. You relate them, that’s the minus, and then the whole thing gets 

integrated . . . . But there’s absolutely not other processing. It’s directly—

the raw signals are directly processed to get you a relative angular rate 

signal. There’s no error correction. There’s no further processing that they 

want to point to in Figure 4, no bias compensation, no common filters. 

Tr. at 86:5–16. To the extent defendants attempt to rely on the equation in Column 5 as showing 

“direct processing,” plaintiff directly addressed this argument in its response brief. “However, 

both variables [the omegas] are shown in the processor after other processing has been 

performed . . . . Thus, the specification confirms that ‘raw’ and ‘directly’ simply mean that the 

data is input from the sensor into the processing element and is ultimately used to determine a 

relative angular rate signal regardless of other processing.” Pl.’s Resp. Cl. Constr. Br. at 13

(emphasis in original). Plaintiff thus argues “[t]he claims are not limited to, as Defendants 

suggest, a computation directly upon the incoming sensor signal itself.” Id. To the extent 

defendants argue for the inclusion of “direct processing” in the Court’s construction based on the 

specification’s disclosure of the equations in Column 5, plaintiff’s reference to the relevant 

omega variables being fed to the processing element after passing through at least a bias 

compensation module defeats such an argument. 

As defendants point out, however, their “argument is not primarily based on the 

specification. It’s based on the disclaimer.” Tr. at 59:4–5. Assuming, arguendo, that a 

limitation later disclaimed during prosecution need not first be disclosed in the specification, the 

Court addresses defendants substantive argument: “throughout . . . the PTAB process, [plaintiff] 

was very clear that the only thing that would get them over [the prior art] was the two-step versus 

three-step [process].” Tr. at 65:14–17. In its briefs, defendants argue “[plaintiff] was incredibly 

direct in explaining that the claims require and are limited to the ‘relative angular rate signal’ 

being directly determined from ‘raw signal data’ from the inertial sensors.” Defs.’ Op. Cl. 

Constr. Br. at 9 (emphasis in original). Reading these arguments together, defendants thus assert 

the so-called “two-step” method requires calculating the relative angular rate signal directly from 

the raw signals measured by the inertial sensors. The Court must therefore review the specific 

statements made by plaintiff at both the PTAB and the Federal Circuit, as well as the final 

written decision of the PTAB and the Federal Circuit’s subsequent opinion on appeal, to 

determine the specific requirements of the “two-step” method. 

The PTAB did not use the “two-step” or “three-step” labels in differentiating the prior art 

from the system of the '159 patent. Rather, the PTAB used only the designations “old way” and 

“new way.” See generally Elbit Systems of America, LLC. v. Thales Visionix, Inc., IPR2015-

01095 (PTAB Oct. 14, 2016), ECF No. 160-2. These designations are, however, synonymous 
- 22 -

with the Court’s reference to both the “old method” (i.e., the “three-step method”) and the “new 

method” (i.e., the “two-step method”). The PTAB observed plaintiff characterized the “old 

method” of computing relative orientation as “first integrating the signal output of each angular 

rate sensor . . . to compute orientation of each relative to ground, and then computing the 

orientation of the object relative to the moving reference frame.” Id. at 14. The PTAB further 

noted plaintiff argued the “new method” calculated relative orientation “by integrating a ‘relative 

angular rate signal’ . . . determined from ‘raw signal data.’” Id. Adopting plaintiff’s arguments, 

the PTAB found the prior art “rel[ies] on the old way and provide[s] no hint or perceived need to 

determine a ‘relative angular rate signal’ prior to determining orientation.” Id. at 15. As such, 

the PTAB concluded “no cited reference teaches or suggests the recited ‘relative angular rate 

signal,’ which can be then integrated to obtain relative orientation.” Id. 

The Federal Circuit, in reviewing the PTAB’s final written decision, initially coined the 

phrases “two-step method” and “three-step method.” See Elbit Systems, 881 F.3d at 1357. The 

Federal Circuit, relying on plaintiff’s expert’s characterization of the technology, described the 

system of the '159 patent as “employ[ing] a two-step method: ‘the raw signal data from the 

inertial sensors . . . is used to determine the relative angular rate signal’; and ‘[t]hat relative 

angular rate signal . . . is then used to calculate relative orientation.’” Id. at 1358 (quoting J.A. 

2112 [Declaration of Dr. Welch, ¶43]). Viewing this “two-step method” with the specification, 

the Federal Circuit further noted the system of the '159 patent calculates relative orientation 

“‘without the need to ever know or measure or calculate the orientation or position of the moving 

platform.’” Id. (quoting '159 Patent at col. 8 37–41). As the Federal Circuit recognized, “[t]his 

eliminates the need to calculate an object’s position relative to the ground.” Id. at 1355. 

The Federal Circuit identified the systems used in the prior art as “calculat[ing] an 

object’s relative orientation using a three-step method.” Id. at 1357. Again relying on plaintiff’s 

expert’s testimony, the Federal Circuit described the “three-step method” as follows: 

First, the orientation of a moving object . . . is calculated with respect to an inertial 

reference frame . . . using inertial sensors mounted to a moving object (e.g., angular 

rate sensors . . .). Next, the orientation of a moving reference frame . . . is calculated 

with respect to the inertial reference frame using inertial sensors mounted to the 

moving reference frame. . . . Finally, the relative orientation of the moving object 

with respect to the moving platform . . . is calculated by resolving the orientation 

calculations. 

Id. at 1357–58 (quoting J.A. 2109–10 [Declaration of Dr. Welch, ¶39]).

The Court thus reproduces the graphic originally provided by plaintiff with the following 

annotations to remove any ambiguity as to what the various “steps” are in both the “two-step 

method” and the “three-step method.” 

New Method: Two-Step Method
- 23 -

Step One Determine relative angular rate signal from 

signal data received directly from inertial 

sensors 

Step Two Use relative angular rate signal to calculate 

relative orientation 

Old Method: Three-Step Method

Step One Calculate orientation of moving object with 

respect to inertial reference frame 

Step Two Calculate orientation of moving reference 

frame with respect to inertial reference frame 

Step Three Calculate relative orientation of moving 

object by resolving orientation calculations 

from steps one and two 

Pl.’s Resp. Cl. Constr. Br. at 2–3. During the Markman hearing, plaintiff’s counsel 

attempted to distance the system of the '159 patent from the “two-step method” label. 

THE COURT: [Plaintiff’s] expert explained [during the Federal Circuit appeal] 

that the two-step method employed by the asserted claims reduces both the 

number of calculations required to determine relative orientation and the 

propagation of errors that inevitably occur when using inertial sensors to track 

motion. . . . [I]sn’t that prohibiting this additional integration? 

PLAINTIFF’S COUNSEL: No, Your Honor. First of all, those are the benefits 

of the invention. . . . And so there’s nothing that says you can’t do other things to 

get from the angular rate to the relative angular rate. And that’s what the claim 
- 24 -

says. It says determined from. And if you want to do it with a bunch of steps, 

you can do it with a bunch of steps. . . . [T]he way that [the Federal Circuit] 

described it was that it has two steps, but they didn’t say that it only ever has two 

steps. 

Tr. at 114:9–115:10. 

Plaintiff’s characterization of the relevance of the “two-step method” highlights an 

important distinction between the Federal Circuit’s previous discussion related to distinguishing 

the system of the '159 patent over the prior art, and the Court’s current exercise of construing the 

claim terms. Plaintiff’s counsel further provided the following, succinct statement on this 

distinction: “[T]he two-step and the three-step have to do with the relative angular rate signal. 

And the fact that in the prior art there was no relative angular rate signal, the angular rates in the 

prior art were not used to form a relative angular rate signal at all . . . . [T]hat is the difference 

between the two-step and the three-step.” Tr. at 97:3–9. As the Federal Circuit held, the overall 

system of the '159 patent operates according to a “two-step method,” whereas the prior art 

operated according to an overall “three-step method.” Elbit Systems, 881 F.3d at 1358. The 

“elimination” of a step by the '159 patent is the result of determining a “relative angular rate 

signal” in place of two previous, independent calculations of the orientation of both the moving 

object and the moving reference frame. Id. Now, at the claim construction phase, the Court 

must determine what it means to determine a relative angular rate signal from the angular rate 

signals measured by the sensors. As plaintiff rightly points out, “if you want to do it with a 

bunch of steps, you can do it with a bunch of steps . . . . [I]nefficient infringement is still 

infringement.” Tr. at 115:9–15. 

Nothing in the previous decisions of the PTAB or Federal Circuit suggest any limitation 

on the number of steps required in determining the relative angular rate signal. The previous 

decisions of both the PTAB and Federal Circuit only require the system of the '159 patent to 

utilize the step of determining the relative angular rate signal in place of the independent 

orientation calculations for both the moving object and the moving reference frame. The only 

requirement recognized by either the PTAB or the Federal Circuit regarding the determination of 

the relative angular rate signal itself is the use of “raw signal data” in making the determination. 

As the Court previously addressed, the use of “raw signal data” is better understood as the 

element responsible for determining the relative angular rate signal receives signal data directly 

from the angular rate sensors. See supra at 18. There is no evidence supporting that either the 

PTAB or Federal Circuit relied on plaintiff’s alleged representations the relative angular rate 

signal is further directly determined from these direct signals as a prerequisite for distinguishing 

the system of the '159 patent over the prior art. 

Beyond the express findings of either the PTAB or Federal Circuit, defendants point to 

specific statements made by plaintiff’s expert during the PTAB and Federal Circuit proceedings

in an attempt to import the term “directly” into the determination of the relative angular rate 

signal. Defendants’ primary evidence is the following quote from plaintiff’s expert: “Inventions 

claimed in the '159 Patent directly use signals from the sensors (i.e., raw signals) on both the 

moving object and moving reference frame to determine relative signals which are used to 

determine relative orientation.” Defs.’ Op. Cl. Constr. Br. at 10 (quoting ECF No. 107-12 at 3)
- 25 -

(emphasis in original). Although defendants urge the Court to read this statement as requiring 

direct determination of the signals from the sensors, the Court finds plaintiff’s interpretation of 

this particular statement equally—if not more—plausible: “‘[A] POSITA reading the statements 

provided would understand that ‘raw’ and ‘directly’ refer to the fact that the processing elements 

required by the claims must simply receive angular rate signal data from the receptive sensors 

and use that data to ultimately determine a relative angular rate.’” Tr. at 116:2–8 (quoting ECF 

No. 170 ¶¶ 15–16 [Declaration of Dr. Welch]). 

In addition to relying on their own expert, plaintiff further relied on statements of 

defendants’ expert in supporting their interpretation of these earlier statements. 

And then if you look at what Dr. Paradiso says, and that’s Defendants’ expert that 

they use here, he says, “In my opinion, these statements in the intrinsic record make 

clear that the claim language, the language of the claim, specifically refers to and 

is limited to relative angular rate signal being determined from raw signals directly 

from the inertial sensor.” So he’s adopting that “determined from,” too. And 

nobody is saying directly computed, not either expert. 

Id. at 116:9–17. As plaintiff points out, when “dealing with disclaimer, it has to be clear and 

unequivocal. And if there are two reasonable interpretations, there’s no disclaimer.” Id. at 

115:23–25. See Aylus Networks, 856 F.3d at 1359 (quoting Omega Eng’g, 334 F.3d at 1325–

26). Accordingly, the Court need not reach which of the parties’ interpretations is the correct 

interpretation. As the Court finds each of the proposed interpretations a plausible reading of the 

statements made in the intrinsic record, the statements are by definition not a “clear and 

unmistakable” waiver of claim scope. “Where the alleged disavowal is ambiguous, or even 

‘amenable to multiple reasonable interpretations,’ [the Federal Circuit has] declined to find 

prosecution disclaimer.” Avid Tech, 812 F.3d at 1045 (quoting Cordis Corp., 339 F.3d at 1359)

(internal citations omitted); see Baxalta Inc. v. Genentech, Inc., No. 19-1527, 2020 WL 5048435, 

at *6 (Fed. Cir. Aug. 27, 2020) (finding the patentee’s claim amendment did “not clearly 

establish disclaimer” where another “plausible” explanation for the introduction of the 

amendment was presented). 

Accordingly, while plaintiff did disclaim the broader use of determining a relative 

angular rate signal using anything other than signals measured by the inertial sensors and sent 

directly to the processing unit, characterizing this disclaimer as to require the relative angular 

rate signal be “computed directly from the raw signals” results in a forfeiture of claim scope 

beyond that which plaintiff disclaimed.2 See Omega Eng’g, 334 F.3d at 1327 (finding “[t]he 

2 Defendants raised an additional argument during the Markman hearing regarding the order of operations in the 

asserted claims: 

[O]nce you integrate, you don’t have a relative angular rate signal. And then what they’re—what 

[it] seems like they might be trying to do is[, and] we just call this the new old way or the new, new 

way, it’s hard to tell. But once you take this relative orientation, they’re suggesting that, you know, 

you can differentiate it into an integrated—into a relative angular rate signal again and then integrate 

it again, and that’s still okay. . . . And so this illustrates to the Court what we think is inappropriate 

about what follows Markman if they get their construction, is they try to say, okay, well this signal 

now, which is a rate, you can—you can differentiate, you can integrate it, it’s already been 

processed, but we’ll still call it at the end of the day a relative angular rate signal. 
- 26 -

district court was therefore correct in finding prosecution disclaimer, but erred in ascertaining the 

scope of the disavowal”). 

 

b. Judicial Estoppel

Defendants further assert an alternative argument in an attempt to preclude plaintiff from 

recovering what defendants view as disclaimed claim scope during prior judicial proceedings. 

According to defendants, plaintiff “is also judicially estopped from arguing that a ‘relative 

angular rate signal’ does not have to be computed from the inertial sensors’ ‘raw signals,’ as 

[plaintiff] now argues with its proposed construction.” Defs.’ Op. Cl. Constr. Br. at 19. 

Defendants cite Supreme Court precedent, defining the doctrine of judicial estoppel as: 

“‘[w]here a party assumes a certain position in a legal proceeding, and succeeds in maintaining 

that position, he may not thereafter, simply because his interests have changed, assume a 

contrary position, especially if it be to the prejudice of the party who has acquiesced in the 

position formerly taken.’” Id. (quoting New Hampshire v. Maine, 532 U.S. 742, 749 (2001)). 

This principle of judicial estoppel “generally prevents a party from prevailing in one 

phase of a case on an argument and then relying on a contradictory argument to prevail in 

another phase.” New Hampshire, 532 U.S. at 749 (quoting Pegram v. Herdrich, 530 U.S. 211, 

227 (2000)). The Supreme Court has identified a series of factors to consider when applying the 

doctrine of judicial estoppel: (1) “a party’s later position must be ‘clearly inconsistent’ with its 

earlier position;” (2) “whether the party has succeeded in persuading a court to accept the party’s 

earlier position, so that judicial acceptance of an inconsistent position in a later proceeding 

would create ‘the perception that either the first or the second court was misled;’” and (3) 

“whether the party seeking to assert an inconsistent position would derive an unfair advantage or 

impose an unfair detriment on the opposing party if not estopped.” Id. at 750–51 (first quoting 

United States v. Hook, 195 F.3d 299, 306 (C.A.7 1999), then quoting Edwards v. Aetna Life Ins. 

Co., 690 F.2d 595, 599 (C.A.6 1982)). 

Defendants’ counsel further noted during the Markman hearing the judicial estoppel 

argument sought to accomplish the same goal as the prosecution history disclaimer argument: to 

prohibit plaintiff from recovering claim scope previously disclaimed based on statements 

inconsistent with their current position. See Tr. at 137:4–12 (“I would just briefly like to remind 

the Court that it’s not just prosecution disclaimer that applies here, it is also judicial estoppel. 

And they’re both equitable doctrines with the same purpose, which is to hold a party to their 

word.”) (emphasis added). Each of defendants proposed “inconsistent statements” identified 

under the judicial estoppel argument were previously analyzed under the Court’s discussion of 

prosecution history disclaimer, as each of these statements appeared during either the IPR 

Tr. at 95:24–96:21. In sum, defendants take issue with whether the asserted claims cover calculating a relative 

angular rate signal by differentiating the relative orientation. Defendants’ argument is thus grounded out of concern 

plaintiff will attempt to read defendants’ system on claim 3 based upon subsequent calculations occurring after the 

relative orientation is calculated. To the extent defendants are attempting to raise infringement-related concerns at 

the claim construction phase, such arguments are premature. Eon Corp. IP Holdings v. Silver Springs Networks, 

815 F.3d 1314, 1319 (Fed. Cir. 2016) (“[T]here are limits to the court’s duties at the claim construction stage. For 

example, courts should not resolve questions that do not go to claim scope, but instead go to infringement . . . .”) 

(internal citations omitted). Accordingly, the Court does not reach such arguments at this stage of the proceedings. 
- 27 -

proceeding or subsequent appeal.3 Accordingly, the Court does not further address defendants 

judicial estoppel arguments. 

4. “inertial sensors” vs. “angular rate sensors” 

Claim 1 introduces a first and second inertial sensor, with the first inertial sensor 

mounted on the tracked object and the second inertial sensor mounted on the moving reference 

frame. '159 Patent at col. 11:52, 53–54. Claim 2, which is dependent on Claim 1, further defines 

each of the first and second inertial sensors as “compris[ing] three angular inertial sensors 

selected from the set of angular accelerometers, angular rate sensors, and angular position 

gyroscopes.” Id. at col. 11:60–64. Claim 3, which in turn depends from claim 2, further narrows 

the angular inertial sensors to “compris[ing] angular rate sensors.” Id. at col 11:61–12:2.

Plaintiff argues claim 3’s language covering “[t]he system of claim 2, in which the 

angular inertial sensors comprise angular rate sensors” defines the claim language of “‘inertial 

sensors’ [to] include ‘angular rate sensors,’ but the inertial sensors are not limited to only angular 

rate sensors.’” Pl.s’ Op. Cl. Constr. Br. at 8 (emphasis in original). Therefore, plaintiff argues 

defendants’ “attempt to narrow the claimed ‘first and second inertial sensors’ to ‘first and second 

angular rate sensors,’ is improper.” Id. Defendants support their proposed claim construction by 

noting the term “comprising” “is a term of art used in claim language which means that the 

named elements are essential,” and argues the Court should interpret the essential elements of 

the claim as requiring the term “angular rate sensors.” Defs.’ Resp. Cl. Constr. Br. at 16–17 

(quoting In re Crish, 393 F.3d 1253, 1257 (Fed. Cir. 2004)). In support of this interpretation, 

defendants point to communications plaintiff made with the Patent Office, which defendants 

argue “form part of the intrinsic record” from which the Court may understand the claim 

language. Id. at 16. 

Plaintiff had previously explained to the Patent Office “[c]laims 3 and 24 of the ‘159 

Patent are limited to systems or methods wherein the raw signals measured by the first and 

second angular rate sensors are used to determine a relative angular rate signal, which is 

integrated to determine the relative orientation of the moving object with respect to the moving 

reference frame.” Patent Owner Response, ECF No. 107-12 at 6 (emphasis added) (“Patent 

Response”). Plaintiff’s proposed claim construction now fails to incorporate this understanding 

of the claim’s structure and scope. The Federal Circuit, on “numerous occasions,” has 

reaffirmed “that ‘[t]he best source for understanding a technical term is the specification from 

3 At the Markman hearing, defendants argued there was at least one position taken during the previous § 101 appeal 

to the Federal Circuit which did not appear in the IPR and patent prosecution history for which judicial estoppel 

would apply to limit the claim scope, but prosecution disclaimer would not: “in addition they’ve said in the [§ 101] 

appeal that the method allows for using of raw data directly from the inertial sensors to determine without external 

input for error corrections the orientation of one moving object relative to another moving object.” Tr. at 137:19–

23. The Court notes, however, plaintiff did present an identical argument during the IPR proceeding: “The '159 

Patent covers a discrete measurement apparatus and method that allows for using raw data directly from IMUs to 

accurately determine, without external inputs or error corrections, the orientation of one moving object relative to 

another moving object, in a self-contained system.” Pl.’s Op. Cl. Constr. Br., Ex. 5 at 19 (plaintiff’s Patent Owner 

Response from the PTAB proceeding). Therefore, the Court’s discussion of prosecution history disclaimer fully 

applies to the “inconsistent statements” defendants identified under the judicial estoppel argument.
- 28 -

which it arose, informed, as needed, by the prosecution history.’” Phillips, 415 F.3d at 1315

(quoting Multiform Desiccants, Inc. v. Medzam, Ltd., 133 F.3d 1473, 1478 (Fed. Cir. 1998)); see 

also Kinik Co. v. Int’l Trade Comm’n, 362 F.3d 1359, 1365 (Fed. Cir. 2004) (“The words of 

patent claims have meaning and scope with which they are used in the specification and the 

prosecution history.”). 

Claim 2, which is dependent on claim 1, includes inertial sensors “in which . . . [each 

inertial sensor] comprises three angular inertial sensors selected from the set of angular 

accelerometers, angular rate sensors, and angular position gyroscopes.” '159 Patent at col. 

11:60–63. Claim 3, which is dependent on claim 2, narrows the angular inertial sensors to 

comprising “angular rate sensors” before stating the orientation of an object is determined by 

integrating “a relative angular rate signal determined from the angular rate signals measured by 

the first and second inertial sensors.” Id. at col 11:64–12:2 (emphasis added). Claim 3 narrows 

the “inertial sensors” comprising of “three angular inertial sensors” in claim 2 to comprise 

specifically of “angular rate sensors.” Id. at col 11:60–12:2. This understanding of the scope of 

claim language is further supported by plaintiff’s explanation of claim 3 as only encompassing 

systems or methods wherein a raw signal is measured “by angular rate sensors . . . used to 

determine a relative angular rate signal.” Patent Response at 6. In construing the meaning of the 

term “first and second inertial sensors” used in claim 3 to measure “the angular rate signals,” the 

Court looks to the prosecution history to understand the meaning of the technical term as used in 

the claim. Phillips, 415 F.3d at 1315. The prosecution history informs the Court the claim 

language of “inertial sensor” should be interpreted as “angular rate sensor” so as to be consistent 

with plaintiff’s description of the claim language in the intrinsic record. At the Markman

hearing, the Court asked for “[p]laintiff’s position” on the Court’s proposed construction of 

claim 2. Tr. at 68:3–5. Plaintiff’s counsel represented they “are okay with the Court’s proposed 

construction.” Id. at 68:6–7. The limitations imposed on claim 3 as dependent on claim 2, the 

intrinsic evidence related to the prosecution history, and plaintiff’s agreement during the 

Markman hearing all support the court’s construction of “inertial sensors” in claim 3 as “angular 

rate sensors.” Phillips, 415 F.3d at 1315.

C. Court’s Construction 

Defendants’ arguments as to disclaimer are accurate to the extent they require the 

processing element to receive raw signals directly from the inertial sensors. Beyond direct 

receipt, however, to the extent defendants attempt to extend the disclaimer argument to the 

exclusion of any further computation by the processing element, such arguments go too far. 

Plaintiff is correct that the extent of the disclaimer ends at the processing elements receipt of the 

“raw” signals “directly” from the sensors.

Plaintiff’s Proposed Construction Defendants’ Proposed Construction (with 

edits) 

signal data representing the rate that the 

tracked object is rotating in the moving 

reference frame determined using signal data 

representing the angular rate of objects 

a signal [signal data] representing the rate at 

which the tracked object is rotating relative to 

the moving reference frame that is computed

directly [determined] from the raw signals
- 29 -

measured by the first and second inertial 

sensors

[data] measured [received directly from] by 

the first and second angular rate sensors

Court’s Construction

Signal data representing the rate at which the tracked object is rotating relative to the moving 

reference frame determined from signal data received directly from the first and second 

angular rate sensors

V. Disputed Claim Term #3: “a relative linear acceleration signal computed from the 

linear accelerometer signals measured by the first and second inertial sensors”

Plaintiff’s Proposed Construction Defendants’ Proposed Construction 

signal data representing the linear acceleration 

of the tracked object in the moving reference 

frame computed using signal data 

representing the linear acceleration of objects 

measured by the first and second inertial 

sensors

a signal representing the linear acceleration of 

the tracked object relative to the moving 

reference frame that is computed directly 

from the raw signals measured by the first and 

second linear accelerometers

A. Parties Arguments

Plaintiff notes “this claim language should be construed in a similar manner as the 

[second disputed claim term].” Pl.’s Op. Cl. Constr. Br. at 16. “Other than replacing ‘angular 

rate’ with ‘linear acceleration,’ the claim phrases only differ by using ‘computed’ rather than 

‘determined.’” Id. Plaintiff thus notes “[b]ecause the remaining portions of the two claim 

phrases do not differ significantly for purposes of resolving the parties’ claim construction 

issues, the construction format . . . should follow the construction format for” the second claim 

term. Id. Defendants note “[t]he analysis for this term is effectively the same as for the [second 

term], as the only real difference is the use . . . of linear accelerometers, as opposed to the use of 

inertial sensors.” Defs.’ Op. Cl. Constr. Br. at 22. Defendants conclude that “[t]he parties 

therefore seem to agree that the ‘relative linear acceleration signal’ term should be construed 

consistently with the ‘relative angular rate signal term.’” Defs.’ Resp. Cl. Constr. Br. at 19. 

The Court provided the parties with the following preliminary construction prior to the 

Markman hearing: “the signal data representing the linear acceleration of the tracked object 

relative to the moving reference frame determined from signal data received directly from the 

first and second linear accelerometers.” Tr. at 9:2–6.

B. Court’s Construction

The parties agree this claim term is to be construed in accordance with that of the second 

disputed claim term. The Court accordingly adopts a similar construction to the second claim 

term discussed above, replacing the applicable terms as follows: “signal data representing the 

linear acceleration of the tracked object relative to the moving reference frame determined from 

signal data received directly from the first and second linear accelerometers.” 
- 30 -

Plaintiff’s Proposed Construction Defendants’ Proposed Construction (with 

edits) 

signal data representing the linear 

acceleration of the tracked object in the 

moving reference frame computed using 

signal data representing the linear 

acceleration of objects measured by the first 

and second inertial sensors

a signal [data] representing the linear 

acceleration of the tracked object relative to 

the moving reference frame that is computed

[determined from] directly from the raw

signals [data received directly from]

measured by the first and second linear 

accelerometers 

Court’s Construction

Signal data representing the linear acceleration of the tracked object relative to the moving 

reference frame determined from signal data received directly from the first and second linear 

accelerometers

VI. Conclusion 

The disputed terms of the '159 patent are interpreted by the Court in this Claim 

Construction Opinion and Order. The Court adopts the construction of the terms as set forth 

herein.

IT IS SO ORDERED.

s/ Ryan T. Holte

RYAN T. HOLTE 

Judge