Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 04/22/2026 has been entered.
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
Applicant's arguments and remarks filed on 04/22/2026 have been fully considered.
Claims 1, 7-10, and 13-19 have been amended.
Claims 1-20 are pending.
Response to Arguments
Applicant’s arguments, see remarks pages 8-11, filed 04/22/2026, with respect to claims 1-20 have been fully considered and are persuasive. The of claims 1-20 has been withdrawn.
Specification
The disclosure is objected to because of the following informalities:
The specification is objected to under MPEP 608.01/37 C.F.R. 1.71 for a material internal inconsistency. Paragraphs [0014] and [0023] are each directed to describing the transition-to-off interval, yet each paragraph erroneously uses the phrase “transition-to-on interval” when describing the publishing steps within that interval. For example, paragraph [0014] states: “publishing, at a first point in time in the transition-to-on interval, a first weighted average…” and “publishing, at a second point in time, later than the first point in time, in the transition-to-on interval, a second weighted average….” Both references in paragraphs [0014] and [0023] should read “transition-to-off interval.” This internal inconsistency appears to be transferred to claims 9 and 18.
Appropriate correction is required.
Claim Objections
Claim 1 objected to because of the following informalities:
Claim 16 is objected to under 37 C.F.R. 1.75(b) for a typographical error. The body of claim 16 consistently uses the plural term “smoothed estimates,” yet the concluding wherein clause contains a singular form: “wherein a proportion in weight of the second one of the smoothed estimate to the second weighted average is greater than….” The reference to “the second one of the smoothed estimate” is internally inconsistent with the plural form “smoothed estimates” used immediately preceding in the body of the claim. The correct term is “smoothed estimates” to match the plural as established in the body. Applicant is required to amend this wherein clause in claim 16 accordingly.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claim 1, 6–10, and 15–19 rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, because the specification, while being enabling for specific types of estimates (position and velocity), does not reasonably provide enablement for "a first estimate". Independent claims 1, 10, and 19 each recite “receiving a first estimate from a navigation engine of a Global Navigation Satellite System (GNSS) receiver” and “processing the first estimate with a first Kalman smoother to generate a first smoothed estimate.” The term “a first estimate” is not limited in the independent claims to any particular type of estimate. Under the broadest reasonable interpretation (BRI), “a first estimate” from a navigation engine of a GNSS receiver encompasses any estimate that a navigation engine is capable of generating, which may include, but is not limited to, position estimates (latitude, longitude, altitude in LLA), velocity estimates (in ENU, NED, or LLA coordinate frames), time estimates (receiver clock bias), heading or bearing estimates, dilution-of-precision (DOP) estimates, satellite availability estimates, and others. However, the specification describes the navigation engine 130 as generating estimates of position, velocity, and time (paragraph [0043]), and provides enabling disclosure for the Kalman smoother processing in only two contexts:
Position estimates: The Kalman smoother 135 is described as operating on the horizontal position and velocity of the GNSS receiver (paragraphs [0045]–[0060]), implemented as parallel latitude and longitude Kalman smoothers (paragraphs [0060]–[0061]) with specifically defined state vectors (equation (1)), state transition matrices (equations (2)–(3)), and measurement models (equation (4)).
Velocity estimates: The specification describes converting velocity estimates from ENU coordinates to LLA coordinates for use in the Kalman smoother (paragraph [0061]) and claims 20 covers this embodiment.
The specification provides no enabling disclosure for Kalman smoother processing of time estimates (receiver clock bias), heading estimates, DOP estimates, or any other GNSS navigation output beyond position and velocity.
Wand Factor Analysis (In re Wands, 858 F.2d 731, Fed. Cir. 1988; MPEP 2164.01(a))
Factor 1: Breadth of the claims: The claims are broad. “A first estimate” without qualification encompasses any output of the GNSS navigation engine. This breadth substantially exceeds the specific types of estimates enabled by the specification (position and velocity).
Factor 2: Nature of the invention: The invention involves the design and application of a Kalman smoother to GNSS navigation data. The design of a Kalman smoother, specifically its state space definition, state transition matrix, process noise covariance Q, and measurement noise covariance R, depends fundamentally on the physical quantity being estimated. A Kalman smoother designed for position estimation has a fundamentally different mathematical structure (state vector, transition equations, noise models) than one designed for receiver clock bias or time estimation.
Factor 3: State of the prior art: Kalman filtering of GNSS position and velocity estimates was well-established at the time of filing, as acknowledged by the specification (paragraph [0054]). However, the adaptation of the specific Kalman smoother architecture described herein (including the fixed-delay super-state formulation and the latitude-longitude coordinate conversion) to other types of GNSS navigation estimates involves design choices not disclosed in the specification and would require substantive engineering effort by persons of ordinary skill.
Factor 4: Relative skill of those in the art: Persons skilled in the art of GNSS signal processing and Kalman filtering are highly skilled. Nevertheless, even such a skilled person would require meaningful guidance from the specification to implement the claimed Kalman smoother processing for types of estimates not disclosed, such as receiver clock bias or heading, because the complete mathematical framework (state space model, noise covariance selection, coordinate transformation) must be tailored to each specific estimated quantity.
Factor 5: Predictability of the art: While GNSS navigation is a mature field, the design of Kalman smoothers for different types of navigation outputs involves non-trivial decisions in state modeling, noise covariance specification, and coordinate transformation. These choices are not predictable from the position-estimation and velocity-estimation disclosures alone.
Factor 6: Amount of direction provided by the inventor: The specification provides detailed mathematical guidance only for horizontal position and velocity estimates (equations (1)–(13), paragraphs [0045]–[0059]) and the latitude-longitude coordinate conversion for position and velocity (paragraph [0061]). No mathematical guidance, state-space formulation, or noise model is provided for other types of estimates that the navigation engine might generate.
Factor 7: Existence of working examples: The specification’s working descriptions are directed exclusively to position estimates (latitude-longitude Kalman smoothers) and velocity estimates (ENU-to-LLA conversion, claim 20). There are no working examples for Kalman smoother processing of clock bias, DOP, heading, or other navigation outputs.
Factor 8: Quantity of experimentation needed: A person of ordinary skill would require undue experimentation to adapt the disclosed Kalman smoother to the full range of possible estimates encompassed by the broad claim language “a first estimate.” The entire mathematical framework must be redesigned for each new type of estimate — including definition of a new state vector, new state transition matrix, new Q and R covariance matrices, and potentially new coordinate transformations — representing undue experimentation across the full scope of the independent claims.
Applying the Wand factors, the specification does not enable the full scope of “a first estimate” as recited in claims 1, 10, and 19. The dependent claims that specify the type of estimate, claims 2, 7, 11, and 16 (position estimates) and claim 20 (velocity estimate), are within the enabling disclosure of the specification. However, the independent claims 1, 10, and 19 encompass a scope broader than what is enabled, rendering those claims and their dependents that do not further limit the type of estimate (claims 6, 8, 9, 15, 17, 18) subject to the enablement rejection.
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 1, 7, 9, 10, 16, 18, and 19 rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 1 recites “receiving a first estimate from a navigation engine of a Global Navigation Satellite System (GNSS) receiver,” “processing the first estimate with a first Kalman smoother to generate a first smoothed estimate,” and “publishing a weighted sum of the first estimate and the first smoothed estimate.” The same language appears in claims 10 and 19. The phrase “a first estimate” does not specify what physical quantity is being estimated. Under the broadest reasonable interpretation, “a first estimate” from a GNSS navigation engine could be a position estimate, a velocity estimate, a time estimate, or any other output of the navigation engine. The specification at paragraph [0043] acknowledges that the navigation engine 130 generates “estimates of position, velocity, and time,” and the specification’s Kalman smoother implementation differs materially depending on which type of estimate is being processed, for example, the latitude-longitude Kalman smoother architecture is specific to position estimates, while the ENU-to-LLA coordinate conversion is specific to velocity estimates (paragraph [0061]).
Because the type of estimate being processed by the Kalman smoother determines the nature of the “first smoothed estimate” and the meaning of the “weighted sum,” the independent claims fail to apprise a person of ordinary skill in the art with reasonable certainty of the scope of the claimed invention. Nautilus, Inc. v. Biosig Instruments, Inc., 572 U.S. 898, 910 (2014). A person of skill in the art cannot determine from the claims themselves whether the Kalman smoother is smoothing position, velocity, time, or another quantity, or what the resulting weighted sum represents, without reference to the specification to resolve this ambiguity. Claims 1, 10, and 19 are therefore indefinite.
Claim Rejections - 35 USC § 101
35 U.S.C. 101 reads as follows:
Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor, subject to the conditions and requirements of this title.
Claims 1-20 rejected under 35 U.S.C. 101 because the claimed invention is directed to non-statutory subject matter. The claim(s) does/do not fall within at least one of the four categories of patent eligible subject matter because the claims are directed to patent-ineligible subject matter. Claims 1–9 recite a method. Claims 10–18 recite a machine (a Global Navigation Satellite System receiver with one or more processors and memory). Claims 19–20 recite a machine (a GNSS receiver with a processor and memory). All claims are directed to statutory categories of invention under 35 U.S.C. § 101. The analysis therefore proceeds to Step 2A. See MPEP § 2106.03.
Step 2A, Prong 1 — Does the claim recite a judicial exception?
Under the framework of Alice Corp. Pty. Ltd. v. CLS Bank Int’l, 573 U.S. 208 (2014), Mayo Collaborative Services v. Prometheus Laboratories, Inc., 566 U.S. 66 (2012), and as set forth in MPEP §§ 2106.04 and 2106.04(a)(2), the independent claims 1, 10, and 19 each recite subject matter that is directed to mathematical concepts - specifically mathematical relationships and mathematical operations constituting a judicial exception (abstract idea).
Regarding claim 1, the claim recites the following limitations:
“receiving a first estimate from a navigation engine of a Global Navigation Satellite System (GNSS) receiver”, this is a data-gathering step;
“processing the first estimate with a first Kalman smoother to generate a first smoothed estimate”, the Kalman smoother is a mathematical algorithm. As the specification discloses in detail at paragraphs [0045]– [0059], the Kalman smoother involves state transition equations, covariance matrix propagation, Kalman gain computation, and matrix operations expressed in equations (1) through (13). These are mathematical relationships within the abstract idea grouping under MPEP § 2106.04(a)(2);
“combining the first estimate from the navigation engine and the first smoothed estimate based on a comparison between a count of valid navigational epochs during a period of time and a reference value”, comparing a numerical count to a numerical reference value, and combining two mathematical quantities conditioned on that comparison, constitute mathematical relationships and operations. As claimed, the “combining” step does not reference any particular structural hardware element of the GNSS receiver performing the combination. The specification discloses a combiner 140 (paragraph [0064] and FIG. 2) as the structural component that performs this function, stating: “some embodiments include a combiner 140 that receives both the estimates generated by the navigation engine 130 and the smoothed estimates generated by the Kalman smoother 135 and combines them.” However, the combiner 140 is not recited in the independent claims. The “combining” step as claimed is therefore a mathematical operation not tied to a specific physical component;
“publishing a weighted sum of the first estimate and the first smoothed estimate”, a weighted sum is a mathematical formula (mathematical relationship). As claimed, “publishing a weighted sum” does not recite the structural component through which the weighted sum is produced and published. The specification expressly identifies the combiner 140 and its output 150 as the structural elements implementing this function (paragraphs [0064]– [0065]), but again, the combiner 140 is not recited in the claims.
The core of the claimed method is therefore: apply a Kalman smoothing algorithm to GNSS navigation data; compare a navigational epoch count to a numerical threshold; compute and publish a weighted mathematical combination. These are mathematical concepts, mathematical relationships (Kalman filter equations), mathematical comparison (count vs. reference value), and a mathematical formula (weighted sum), each constituting an abstract idea. The claims therefore recite a judicial exception at Step 2A Prong 1. The same analysis applies to claims 10 and 19, which recite processor-executed instructions that carry out the same mathematical steps.
Step 2A, Prong 2 — Does the claim integrate the judicial exception into a practical application?
See MPEP § 2106.04(d). The analysis considers all claim limitations, not just those identified as the judicial exception. See August 4, 2025 USPTO Memorandum (Reminders on evaluating subject matter eligibility of claims under 35 U.S.C. 101) and Ex Parte Desjardins, Appeal No. 2024-000567 (PTAB Sept. 26, 2025, designated precedential Nov. 4, 2025).
The additional elements in claim 1 beyond the mathematical concepts identified above are: “a GNSS receiver” and “a navigation engine.” While a GNSS receiver is a specific technological system and not a generic computer in the abstract, the operative question under Alice is whether the additional elements impose a meaningful limit on the mathematical concepts, such that the claim covers a practical application and not the abstract idea itself. Alice Corp., 573 U.S. at 223.
Improvements consideration: The specification discloses a specific technical improvement to the GNSS receiver, the combiner 140 that, operating in coordination with the Kalman smoother 135, manages warmup, transition-to-on, on, and transition-to-off intervals to avoid erroneous estimates at startup and avoid discontinuities in the published position solution, thereby improving smoothness and reducing spec-outs (paragraphs [0063]–[0067]). Per Ex Parte Desjardins (reaffirming Enfish, LLC v. Microsoft Corp., 822 F.3d 1327, Fed. Cir. 2016), a claim directed to an improvement to the functioning of a specific technology or technical field may be patent-eligible where the improvement is reflected in the claims. However, the improvement in the present case is achieved through the specific architectural cooperation of the combiner 140 and the Kalman smoother 135, including the combiner’s control logic for managing the warmup, transition, and on/off states. The independent claims do not recite the combiner 140, and as a result, they do not reflect the specific technical improvement disclosed in the specification. Without the combiner 140 (or structurally equivalent language), the claim’s “combining” and “publishing” steps remain generic mathematical operations applied to GNSS data.
Apply it consideration: The claim steps, taken as a whole, use the GNSS receiver and its navigation engine as a tool on which to apply the abstract mathematical concepts. The claims do not recite the specific structural components (combiner 140 and Kalman smoother 135) that distinguish the disclosed GNSS receiver from one that merely executes mathematical calculations. Per the August 4, 2025 USPTO Memorandum, examiners should consider whether the claim recites only the idea of a solution or outcome, or whether it covers a particular solution to a technological problem. Here, the claims recite only the outcome (publishing a weighted sum of GNSS estimates) and the mathematical basis for producing it (Kalman smoothing + epoch count comparison), without specifying the structural components through which this outcome is achieved in the GNSS receiver.
For claims 10 and 19 (apparatus claims), while the recitation of “one or more processors” and “a memory storing instructions” provides machine implementation, these are generic computing components. The instructions stored in memory carry out the same mathematical steps identified above without tying them to the specific architectural components of the GNSS receiver (combiner 140, Kalman smoother 135) that achieve the disclosed technical improvement.
Accordingly, the claims do not integrate the judicial exception into a practical application at Step 2A Prong 2. The analysis proceeds to Step 2B.
Step 2B — Do the additional elements amount to significantly more?
At Step 2B, the additional elements - “GNSS receiver” and “navigation engine” (for method claims 1–9) and “one or more processors,” “memory,” and associated instructions (for apparatus claims 10–20) - are evaluated to determine whether they amount to significantly more than the judicial exception. See MPEP § 2106.05.
A GNSS receiver that receives satellite signals and a navigation engine that generates position/velocity/time estimates are well-understood, routine, and conventional components in the GNSS field, as confirmed by the specification itself at paragraphs [0042]– [0043]. The application of Kalman filtering to GNSS navigation data is acknowledged by the specification as a known technique. Weighted averaging of navigation estimates is similarly well-established. The additional elements, individually and in combination, do not add significantly more than the judicial exception itself.
Therefore, claims 1–20 are rejected under 35 U.S.C. 101 as directed to patent-ineligible subject matter.
Allowable Subject Matter
Claims 1–20 would be allowable if amended to overcome the rejections under 35 U.S.C. 101, 112(a), and 112(b) set forth in this Office Action, without the addition of new matter. Applicant is specifically advised to consider the following amendments:
35 U.S.C. 101 rejection: amend the independent claims to recite the combiner as the structural component performing the combining of the first estimate and the first smoothed estimate and publishing the weighted sum, thereby tying the mathematical operations to the specific hardware component that achieves the technical improvement to the GNSS receiver’s architecture as disclosed in the specification. Claims directed to the warmup, transition-to-on, on, and transition-to-off intervals (claims 7–9 and 15–18) should further be amended to recite the role of the combiner in managing those intervals in coordination with the Kalman smoother.
35 U.S.C. 112(a) rejection: limit “a first estimate” in the independent claims to a specific type of estimate within the scope of what is enabled by the specification (e.g., “a first position estimate” or “a first velocity estimate”), consistent with the enabling disclosure of the specification.
35 U.S.C. 112(b) rejection: specify in the independent claims the type of quantity being estimated, so that the scope of “a first estimate” and “a first smoothed estimate” is clearly defined; and correct the preposition “to” to “in” or an equivalent unambiguous term in the wherein clauses of claims 7, 9, 16, and 18 to clarify the fractional weight relationship within the weighted average.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to REMASH R GUYAH whose telephone number is (571)270-0115. The examiner can normally be reached M-F 7:30-4:30.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Resha H Desai can be reached at (571) 270-7792. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/REMASH R GUYAH/Examiner, Art Unit 3648
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