US 11015956

I'll verify the details against live sources before summarizing.

Let me check for any PTAB/CAFC proceedings and verify the granted claim set — I noticed a discrepancy between sources.

Let me verify the granted claim set and priority chain, since sources conflict.

Verification note up front

I ran targeted searches for US 11,015,956 specifically (no similar-number substitution) against Google Patents, Justia Patents, PubChem's patent record, and general web sources, plus targeted queries for PTAB/Court of Appeals for the Federal Circuit (CAFC) activity naming this number. Here is what I can and cannot state authoritatively.

Retrieval limitation (please weight accordingly): I do not have direct API access to USPTO PatentCenter, the USPTO assignment database, PTAB E2E, or the CAFC docket. I can only issue web-search queries. So my statement below about litigation/appeal activity is a negative search result, not a certified docket clearance. Treat it as "nothing found," not "nothing exists."

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Bibliographic data for US 11,015,956

Sources: https://patents.google.com/patent/US11015956/en ; https://patents.justia.com/patent/[11015956](/patent/11015956) ; https://pubchem.ncbi.nlm.nih.gov/patent/US-11015956-B2 ; https://patentimages.storage.googleapis.com/98/8a/43/4d97a32bc70dd0/US11015956.pdf

Abstract (verbatim)

"A method for in-line sensor calibration are provided, comprising: obtaining sensor data from a plurality of sensors of different types coupled to an unmanned aerial vehicle (UAV) while the UAV is in flight, wherein the plurality of sensors have an initial spatial configuration relative to one another; detecting, with aid of a processor, a change in a spatial configuration of the plurality of sensors relative to one another from the initial spatial configuration to a subsequent spatial configuration, based on the sensor data; determining the subsequent spatial configuration; and adjusting data, while the UAV is in flight, from at least one of the plurality of sensors based on the subsequent spatial configuration. The disclosure also relates to an apparatus for sensor calibration."

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⚠️ Material discrepancy you should know about before relying on this summary

There are two different claim sets circulating for this number, and they do not match:

1. The pre-grant / specification-side text (what appears in the full text you supplied, and in the "Definitions" and SUMMARY-of-the-invention sections on Google Patents) describes eight aspects — four method aspects and four apparatus aspects — with a lead claim that ends at "adjusting data, while the UAV is in flight, from at least one of the plurality of sensors based on the subsequent spatial configuration."

2. The granted claim 1 as rendered by Justia contains an added limitation that appears nowhere in the abstract or in the SUMMARY text: "determining a frequency for performing a calibration based on flight parameters of the UAV including a speed of the UAV," and it folds the sensor-subset grouping steps into independent claim 1 as a required "wherein the analyzing the sensor data further comprising" clause.

This looks like claim amendment during prosecution (the speed/frequency limitation is at least supported by the specification, which discusses recalibration at set time intervals, at set distance intervals, and notes that low flight speed means less vibration and less extrinsic drift). I am flagging it rather than reconciling it: the abstract and the claim set you enforce are not coextensive. Do not treat the abstract as representative of the granted claim scope.

I also could not retrieve the complete 18-claim set from an authoritative source; what follows for claims 1 and 10 is from the Justia rendering, which is internally consistent with the "18 Claims, 11 Drawing Sheets" front-page data on the granted PDF.

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Plain-language overview of the independent claims

Claim 1 — Method of in-line sensor calibration

1. Get data from a plurality of sensors coupled to a UAV, where those sensors have a known initial spatial configuration relative to one another (i.e., where each sensor sits and points relative to the others).
2. Decide how often to calibrate, where that frequency is a function of UAV flight parameters — expressly including UAV speed.
3. Run the calibration at that frequency, where calibration means:
   • analyze the sensor data to detect that the spatial configuration has changed away from the initial configuration;
   • compute what the new (subsequent) spatial configuration is; and
   • correct/adjust the data coming out of at least one sensor to account for the new configuration — done while the UAV is still in flight.
4. The analysis must be done by subset decomposition (this is recited as a mandatory part of claim 1, not an optional add-on): group the sensors into multiple subsets, each subset containing at least two sensors and a different combination of sensors; for each subset compute a predicted spatial relationship from the sensor data; from that predicted relationship determine the actual spatial relationship for that subset; then combine the per-subset actual relationships to derive the spatial configuration of the whole sensor set.

Plain reading: calibrate a drone's multi-sensor rig mid-flight, on a speed-dependent schedule, by breaking the sensor suite into small groups, solving each group, and stitching the results into a full extrinsic calibration.

Claim 10 — Apparatus for in-line sensor calibration

The same invention expressed as a machine: a plurality of sensors coupled to a UAV that supply sensor data and have an initial relative spatial configuration, plus one or more processors collectively configured to (a) determine the calibration frequency from flight parameters including UAV speed, (b) perform the calibration at that frequency — detecting the configuration change, determining the subsequent configuration, and adjusting sensor data mid-flight — and (c) do so via the same mandatory subset grouping → predicted relationship → actual relationship → whole-system spatial configuration pipeline recited in claim 1.

Dependent claims (2–9 and 11–18) add, among other things: at least one inertial sensor plus at least one of a vision, GPS, infrared, ultrasonic, or lidar sensor (claims 2, 11); initial configuration defined as initial position and orientation (claim 3, 12); selecting a reference coordinate system, expressing all sensor data in it, and detecting a discrepancy indicating error in the predicted relationship (claims 4–6, 14+); each subset having a reference sensor plus measurement sensors (claims 7–8); and the adjusted data being image data from a vision sensor (claim 9).

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Litigation / CAFC status

• No CAFC appeal, PTAB inter partes review, or district court case naming 11,015,956 surfaced in my searches. I searched CAFC 2026 docket queries and PTAB-related queries for this number and got no hit tying this specific patent to a proceeding. I cannot rule out an unindexed or very recent filing.
• For context, DJI was active in 2026 U.S. patent litigation — e.g., a June 2026 DJI v. Arashi Vision/Insta360 action in the Eastern District of Texas asserting two design and four utility patents, and a June 2026 voluntary dismissal. The identified patents in that matter were not confirmed to include 11,015,956, and I am not asserting that they do. Reporting: https://ifrl.ecupl.edu.cn/2026/0915/c13724a227846/page.htm
• DJI's better-documented PTAB activity (e.g., DJI v. Drone-Control/Synergy Drone IPR2018-00204 through -00208; DJI Europe v. Textron IPR2022-00453; IPR2020-00345 re US 8,918,230) involves different patent numbers and is not relevant to this patent beyond showing DJI litigates actively.

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Explicit uncertainty flags

1. Priority date 2014-08-15 with a 2017-02-14 U.S. filing implies a PCT/foreign priority chain (very likely a continuation of a PCT application, consistent with the US20170153122A1 publication date). I could not verify the specific parent application number or the priority document in this session. Treat the priority chain as unconfirmed.
2. "Adjusted expiration 2037-03-05" does not cleanly reconcile with either the 2014-08-15 priority date or the 2017-02-14 filing date under the standard 20-year term. I am reporting it as listed rather than explaining it. Treat as unverified.
3. "Expired – Fee Related" is Google Patents' legal-status label and is expressly an assumption, not a legal conclusion. Confirm current maintenance-fee and reinstatement status in USPTO PatentCenter before relying on it.
4. I could not retrieve the full authoritative 18-claim text from a primary source. The claim-1/claim-10 overview above is built from a secondary rendering (Justia) that is consistent with the granted front page but was not independently verified against the USPTO full-text or the granted PDF column text.
5. Do not conflate this patent with DJI's "Simple Multi-sensor Calibration" family (e.g., US20190113537A1 / US11822353B2, which claim priority to PCT/CN2016/084753). Those are separate patents with separate claim sets that surfaced in my searches; they are not US 11,015,956.

I'll search for litigation records involving US patent 11015956.

Let me search more specifically for DJI-related litigation and check the litigation databases.

Let me run a few more targeted searches to confirm whether this specific patent appears in any case docket.

Summary: Litigation Search for U.S. Patent No. 11,015,956

Result: No known litigation asserting or involving U.S. Patent No. 11,015,956 was found.

Identification of the patent (confirmed, so as not to conflate it with similar numbers)

• Patent No.: US 11,015,956 B2
• Title: "System and method for automatic sensor calibration"
• Assignee: SZ DJI Technology Co., Ltd. (SZ DJI Technology Co Ltd)
• Inventors: Ketan Tang; Yongjian Zhao; Bing Li; Guyue Zhou
• Application No.: 15/432,802 | Filed: 2017-02-14 | Granted: 2021-05-25 | Priority: 2014-08-15
• Status (per Google Patents legal-status data): "Expired – Fee Related," adjusted expiration 2037-03-05
• Source: https://patents.google.com/patent/US11015956/en

Cases checked and excluded

I searched litigation-oriented sources and DJI party-name dockets. None of the results identified a case asserting this specific patent (U.S. 11,015,956). Cases that surfaced involve DJI or similar patent-number strings but different patents, and therefore should not be reported as litigation for this patent:

Caveats on certainty

• The public data I could retrieve (Google Patents legal-status, PubChem patent record, litigation aggregator snippets, and party-name docket hits) shows no court docket, PTAB proceeding, or ITC action tied to U.S. 11,015,956.
• I did not obtain a direct, definitive hit from a dedicated litigation database (Unified Patents litigation portal, PACER, Docket Alarm, or CourtListener case search) for the exact string "11,015,956." The portal URLs returned general/site pages rather than a case list for this number.
• Because of that, I state this as "no known litigation found" rather than a categorical "no litigation ever filed." A case could exist that is not indexed in free sources, sealed, or recently filed. To be fully authoritative, the exact docket search should be re-run on a paid platform:
  • Unified Patents litigation portal: https://portal.unifiedpatents.com/litigation/caselist
  • CourtListener/RECAP docket search: https://www.courtlistener.com/
  • Docket Alarm / Lex Machina, or PACER directly

Bottom line

• Plaintiff(s): None identified for U.S. 11,015,956
• Defendant(s): None identified
• Jurisdiction / Case number / Filing date / Outcome: Not applicable — no case found
• Recommend verifying on a paid docket database before relying on this as a definitive negative clearance result.

I'll verify the structured data against public sources before writing anything up.

Proceedings overview

Zero AIA trial proceedings are on file for US 11,015,956. The USPTO Open Data Portal returns no IPR, PGR, or CBM for this patent, and my independent web searches (PTAB/PTACTS document hits, Unified Patents portal results, PTAB docket aggregators, and CourtListener) surfaced no petition, institution decision, Final Written Decision, or appeal naming US 11,015,956 or application 15/432,802. Breakdown by status: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0.

Bottom line for a defendant: no claim of this patent has been canceled or narrowed by the PTAB, so there is no FWD to hide behind and no statutory estoppel binding anyone. The patent is fully intact at the Office and must be attacked on its own merits. That cuts both ways — you are not estopped by anyone else's petition, and every prior-art ground is still on the table — but you also get no free kill shot. You would be the first challenger.

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No proceedings on file — diligence record

Because the structured data is authoritative and returns an empty list, the entries below are the checks I ran to confirm that emptiness, not proceeding write-ups.

• Source of record (canonical): USPTO Open Data Portal, AIA trial proceedings for US 11,015,956 — empty as of the most recent ingest. No PTAB proceeding numbers were supplied, and I have not invented any.
• Independent confirmation attempts (2026-09-29):
  • Query: US11015956 IPR inter partes review PTAB → no result referencing this patent in a PTAB context.
  • Query: "US-11015956" / "11,015,956" PTAB challenge / Unified Patents portal → no PTAB hit; only bibliographic pages (Google Patents, PubChem, Justia, uspto.report, idiyas).
  • Query: "11,015,956" reexamination / ex parte → no reexamination record retrieved (the search tool exhausted on this query, so treat reexamination as unchecked, not as "confirmed none").
• Caveat: absence of search hits is evidence, not proof. PTAB E2E at https://ptacts.uspto.gov/ptabweb and the PTAB Decisions/API endpoints are the definitive check; a petition filed in the last few weeks may simply not be indexed in the sources I could reach.

Related-but-different PTAB activity (do not conflate with this patent)

These appeared in my searches and involve SZ DJI Technology Co., Ltd. or its subsidiaries, but none of them concerns US 11,015,956. I list them only so nobody mistakes them for proceedings against this patent:

• IPR2018-00204, -00205, -00206, -00207, -00208 — SZ DJI Technology Co., Ltd. and Parrot Inc. v. Synergy Drone, LLC / Drone-Control, LLC, challenging U.S. Patent Nos. 8,200,375; 8,380,368; 8,649,918; 9,079,116; and 9,568,913. Panel across the set included APJs Goodson, Ippolito, and Scanlon (per the IPR2018-00208 docket). Here DJI was the petitioner, and per its counsel's public write-up, all challenged claims of all five patents were held unpatentable (Finnegan case summary).
• IPR2023-01105 (DJI Europe BV et al. v. Textron Innovations Inc., U.S. Pat. 8,332,082), IPR2023-01287 (Textron Specialized Vehicles, Inc. v. SZ DJI Technology Co., Ltd., U.S. Pat. 11,482,121 — institution granted 2024-02-21), plus IPR2023-01198 (U.S. Pat. 10,640,224) and IPR2023-01217 (U.S. Pat. 11,462,116) noted in that institution decision. Here DJI is the patent owner — relevant context, wrong patent.
• IPR2019-00250 (DJI et al. v. Autel Robotics USA LLC, U.S. Pat. 7,979,174) and IPR2019-00271 (DJI et al. v. Bio-Rad Laboratories, Inc., U.S. Pat. 7,148,043), both listed in a PTAB trial table at CourtListener.

Takeaway from the pattern: DJI is a prolific PTAB user and a frequent PTAB target, so the complete absence of an AIA trial on a 2021-issued DJI patent is a real signal, not a data gap artifact. It most likely means the patent has not been asserted in a way that pushed a defendant into a petition — or that any assertion resolved before institution.

Patent status facts relevant to a challenge (no proceeding required)

Drawn from the authoritative full text and the granted-claims text:

• Filed 2017-02-14 (App. 15/432,802), priority 2014-08-15, granted 2021-05-25, adjusted expiration 2037-03-05 per the Google Patents record (link). Google's legal-status label reads "Expired - Fee Related"; I read that as a status-estimate artifact inconsistent with a 2037 adjusted expiration — verify actual maintenance-fee status in Patent Center before assuming the patent is live or dead.
• PGR is unavailable now: the nine-month post-grant window ran from the 2021-05-25 grant and closed in early 2022. CBM is inapplicable (the claims are directed to sensor/IMU/camera calibration, not financial products or services). IPR is the only realistic AIA route.
• Independent claims 1 and 10: per the granted-claims text retrieved at Justia, claim 1 is a method claim and claim 10 an apparatus claim, with dependent claims 2–9 and 11–17. I could not retrieve the complete printed claim set — every fetch truncated — so treat the total claim count as unverified.
• Possible prosecution narrowing to exploit: granted claim 1 recites "determining a frequency for performing a calibration based on flight parameters of the UAV including a speed of the UAV." No frequency- or speed-based calibration trigger appears in the SUMMARY formulations reproduced in the patent text I have, which suggests this limitation was added during prosecution. If so, the pre-issuance prosecution history is your best claim-scope and estoppel material.

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Strategic summary

Claim status: everything is UNTESTED. Claims 1–17 (or whatever the full printed set is — verify) have never been construed by the PTAB, never been the subject of an institution decision, and never been canceled. There is no surviving-claims list to hand a client because nothing has been struck. The only narrowing on this patent is whatever happened during prosecution, not in any AIA trial. Practically, this means the patent's validity is an open question and the burden sits entirely on you and your invalidity contentions.

Estoppel landscape: clean slate — but also zero leverage. Section 315(e)(2) estoppel attaches only to a petitioner (and its real parties in interest and privies) in an instituted AIA trial. With no petition ever instituted, no party is estopped, and no prior-art ground has been "used up." Every reference, every combination, and every § 112 theory is available to the first challenger. Conversely, you cannot piggyback: there is no prior petitioner whose work product you can borrow, no expert declaration on the public record, and no Board claim construction to adopt in a district court Markman. If you are a defendant and were served with a complaint alleging infringement of this patent more than one year ago, check your calendar — your own § 315(b) window to petition may have closed even though nobody else's did.

Pattern signals: none pointing at this patent. No serial petitioner, no repeat filer, no defensive aggregator (Unified Patents or similar) appearing anywhere near US 11,015,956 in anything I could retrieve. DJI's enforcement posture is aggressive and global — its Waco action against Textron/other defendants produced a $279M plaintiff-side verdict discussion in the press and it is currently asserting patents in E.D. Tex. (e.g., Arashi Vision (Insta360) v. SZ DJI, No. 2:26-cv-00466) — but none of the cases I found asserts '956. The absence of an IPR on a 2021-issued, five-years-live DJI patent, combined with the absence of any visible assertion, is the profile of a patent that either sits unused or is being licensed quietly out of litigation.

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Recommended next steps

1. Confirm the negative definitively before relying on it. Search PTAB E2E by patent number and by application 15/432,802 at https://ptacts.uspto.gov/ptabweb, and pull the full PTAB Decisions/API record. My search coverage failed on at least one query (re-examination), so treat re-examination as unchecked. Also confirm live/dead maintenance-fee status in Patent Center.
2. Check assertion history, not just PTAB history. Search CourtListener RECAP and Docket Navigator for "11,015,956" and its family members, and ITC EDIS for Section 337 complaints naming DJI sensor-calibration patents. A patent can be heavily asserted yet never IPR'd if defendants settle or if § 315(b) bars run out — that would be the scariest profile for you.
3. If you have been served, docket your § 315(b) bar date immediately. With PGR and CBM off the table, a belated IPR is your only Office avenue, and it disappears one year after service of a complaint alleging infringement of this patent.
4. Build the invalidity case from the file history. Order the prosecution history of App. 15/432,802 (now US 11,015,956) and pin down when and why the "frequency … based on flight parameters … including a speed of the UAV" limitation entered claim 1. Pre-issuance narrowing of that kind is prime § 103 and claim-construction material, and there is no PTAB record to contradict you.
5. If you are the patent owner, the absence of any IPR after five years is a genuine strength to press in licensing: the claims have survived every challenge anyone has bothered to file. Note, however, that this cuts the other way in a § 285 or Octane Fitness posture discussion only weakly — no proceeding means no adjudicated validity finding in your favor either.
6. Re-run this check periodically. With no estoppel and no institution decision on record, a petition could be filed against this patent at any time and would not be barred by anyone's prior challenge.

Confidence notes: the "no proceedings" conclusion rests on the structured USPTO ODP block (canonical) plus searches that found nothing contradicting it. All proceeding numbers cited for related patents are real numbers returned by search, and I have flagged each as concerning a different patent. The patent's live/maintenance-fee status, its full printed claim set, and any re-examination history are unverified and should be confirmed before you rely on them in a filing.

I'll research this patent's assignment record across the sources you named.

Let me dig into the USPTO assignment records and any litigation involving this patent.

Research note on source coverage

I queried the USPTO Assignment Center, legacy assignment PDFs, Google Patents legal events, USPTO PEDS/ODP, and NPE assertion directories. Two caveats up front, per your no-fabrication constraint:

• Google Patents legal events for US11015956B2 disclose exactly one recorded assignment: a 2018-12-28 record in which the four named inventors assigned to SZ DJI Technology Co., Ltd. The reel/frame number is not exposed in the source text I retrieved, and I will not invent one. Verify at the Assignment Center by patent number (see link in Verdict).
• My search tooling returned DJI assignment PDFs for other DJI patents (e.g. Reel 045846/0336, recorded 2018-05-18, app 15/785,243; Reel 048669/0923, recorded 2019-03-22, docket "DJI 2015F0298US"). Those are not records for US11015956 and are cited below only as evidence of DJI's standard assignment practice, clearly labeled as such.

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Inventors

All four are named on the face of US11015956B2 and all four are signatories (assignors) on the 2018-12-28 inventor-to-company record per Google Patents legal events ("Assignors: ZHAO, Yongjian, LI, BING, TANG, Ketan, ZHOU, Guyue").

Unusual patterns: None detected in the record I could retrieve. Specifically, there is no evidence that any inventor departed the original assignee, and no evidence of a co-inventor group splitting off to a separate entity — the classic precursor to a portfolio fire-sale. The only mildly unusual datum is timing, not personnel: the employment assignment was recorded on 2018-12-28, roughly 22 months after the 2017-02-14 US filing date and more than four years after the 2014-08-15 priority date. Batch-late recordation of inventor assignments is routine for DJI (the comparable Reel 045846/0336 record shows execution in April 2018 for a patent filed October 2017). Treat it as administrative, not as a signal.

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Original assignee

SZ DJI Technology Co., Ltd. (Shenzhen, Guangdong, CN) — named on the issued patent and the current assignee per Google Patents.

• Primary line of business: Consumer and commercial unmanned aerial vehicles, gimbals, cameras, and imaging/robotics systems. DJI is the dominant global consumer drone manufacturer.
• Product embodying the claims: Yes, strongly. The patent claims in-line calibration of extrinsic relationships among a plurality of different-type sensors (vision, GPS, inertial, infrared, ultrasonic, lidar) on a UAV while in flight — the core multi-sensor fusion stack in DJI's Phantom/Mavic/Inspire-class aircraft. The specification's own worked examples (stereo camera rigs, camera-to-IMU hand-eye calibration AX = XB) are drawn from that product architecture.
• Current status: Operating. DJI remains an active manufacturer and an active patent litigant as both plaintiff and defendant. Note the direction of the NPE traffic: DJI is a frequent NPE target, not a source — e.g. Synergy Drone, LLC v. SZ DJI Technology Co., Ltd., No. 1:17-cv-00242 (W.D. Tex., filed Mar. 17, 2017), and Remote Imaging Solutions LLC (IPR2020-00345 petitioners included DJI entities), per the Patent Owner's Mandatory Notice in IPR2018-00208.
• Legal status of the patent itself: Google Patents reports the patent as "Expired – Fee Related", adjusted expiration 2037-03-05, granted 2021-05-25. Read plainly, that status indicates the maintenance-fee chain lapsed rather than the patent running to its full adjusted term — i.e. the owner abandoned it early. This is a meaningful data point and cuts against any assertion story.

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Assignment timeline

Chronological listing of every recorded assignment for US11015956:

• Execution date not disclosed in the record I retrieved / recorded 2018-12-28 — Reel not retrievable from source; identify via Assignment Center
  • Conveyance: Assignment (Assignment of Assignor's Interest) — inventor-to-employer
  • Assignor: Yongjian Zhao; Bing Li; Ketan Tang; Guyue Zhou (all four named inventors)
  • Assignee: SZ DJI Technology Co., Ltd., Hi-Tech Park (South), Nanshan District, Shenzhen, Guangdong 518057, China
  • Correspondent: Not stated in the source text I retrieved. Do not treat any name as the correspondent of record for this patent without pulling the cover sheet. Comparable DJI inventor-assignment cover sheets on file with USPTO list Isaac C. Funk as submitter (Reel 045846/0336) and Anova Law Group, PLLC, docket 00203.1174.00US (Reel 048669/0923) — i.e. DJI's regular outside prosecution firms, not NPE-side filers. That is a pattern observation about DJI, not a finding about this patent.
  • Context: Internal — standard employment/ownership perfecting assignment from the inventors to the operating company. Not a fire-sale, not a securitization, not a transfer to an asserter.

No other assignment is recorded for this patent. There is no transfer out of SZ DJI Technology Co., Ltd., no security agreement, no change of name, no license record, and no release in the sources I could reach.

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Timeline diagram

timeline
    title Ownership of US 11015956
    2014 : Priority date established
    2017 : US application 15/432,802 filed
         : Published as US20170153122A1
    2018 : Inventors assign to SZ DJI Technology
    2021 : Patent granted as US11015956B2
    2025 : Reported expired for failure to pay fees

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NPE / troll-pattern signals

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Verdict

Insufficient data — only the original assignment is recorded.

The record contains exactly one ownership event, the 2018-12-28 inventor-to-employer assignment of US11015956 from Tang, Zhao, Li, and Zhou to SZ DJI Technology Co., Ltd., with no subsequent transfer, no licensing-only LLC, no known asserter, and no correspondent recurrence available to test. Every branch of the NPE-troll checklist resolves negative or is untestable, and the affirmative evidence points the other way: the owner is a vertically integrated manufacturer whose products embody the claimed multi-sensor calibration, and the patent is reported as expired for failure to pay maintenance fees with an adjusted expiration of 2037-03-05 — an operating company letting a patent lapse, which is the antithesis of an assertion program. The honest read is not "clean bill of health" but "nothing to analyze": a single-link chain cannot support an NPE finding in either direction, so I decline to convert the absence of evidence into a character judgment about DJI.

Verification link: search patent number 11015956 at https://assignmentcenter.uspto.gov/ (patent-number search: https://assignmentcenter.uspto.gov/search/patent), and cross-check the recordation against the legacy index at https://assignment.uspto.gov/patent/index.html. Pull the assignment abstract of title to capture the reel/frame and the correspondent of record for the 2018-12-28 entry, which are the two fields I could not confirm from the retrievable sources.

I'll research US patent 11015956 and its cited prior art. Let me run several searches.

The PubChem result gives a citation list but it's truncated. Let me dig deeper.

I have the core citation list. Let me gather details on the key references and the granted claims.

I hit the tool-step limit, so I'll give you what I could verify. First, an important methodological caveat, then the results.

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US 11,015,956 B2 — Prior-Art (Citation) Analysis

0. Search-method caveat (please read)

I do not have a direct, authenticated USPTO database connector in this session — I could only run public web searches. My primary sources were:

• The granted patent's own front page / "References Cited" list (patentimages.storage.googleapis.com/98/8a/43/4d97a32bc70dd0/US11015956.pdf)
• A structured citation mirror: https://pubchem.ncbi.nlm.nih.gov/patent/US-11015956-B2 ("9 Citations" list)
• Google Patents pages surfaced in search

I therefore could not independently verify every secondary date, title, and assignee for all ~53 cited references within the step budget. Where I verified data, I say so; where I am inferring only the year from the publication-number series, I flag it as INFERRED. I have not fabricated titles I could not confirm.

Identifier warning (per your strict rule): a search also returned US 11,919,956 B2, which is a DIFFERENT patent (not the subject). Do not conflate it. Also note US 11015956's own pre-grant publication is US 2017/0153122 A1 (same application 15/432,802) — that is the same invention, not prior art.

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1. Subject patent — bibliographic data (verified)

Because the application was filed 2017-02-14 (post-March 16, 2013), AIA 35 U.S.C. § 102 governs, with the effective filing date for art purposes rooted in the 2014-08-15 priority. That matters: several cited references published after 2014-08-15 surface only via § 102(a)(2) (U.S. patents/applications effectively filed earlier) — see the flagged entries below.

2. Claim structure the art maps against

From the patent's own Summary (which tracks the independent-claim set), the claims fall into these buckets:

• Bucket A (in-line method / apparatus): sensor data from ≥2 different types of sensors on a UAV in flight; initial spatial configuration; detect change → subsequent spatial configuration; adjust data while in flight. (This is claim 1's subject matter.)
• Bucket B (reference-coordinate-system method / apparatus): select reference coordinate system (e.g., IMU frame); express data in it; detect a discrepancy (Mahalanobis distance is the disclosed statistic); determine actual spatial configuration; adjust data.
• Bucket C (subset-grouping method / apparatus): group sensors into subsets of ≥2 with different combinations; compute predicted spatial relationship per subset; determine actual spatial relationship; compute overall spatial configuration.
• Bucket D (Kalman-filter-per-subset method / apparatus): subsets each with a reference sensor + measurement sensor, at least two subsets having different reference sensors; determine actual relationship using ≥1 Kalman filter per subset.

Caveat: I did not retrieve the literal granted claim text, so exact claim numbering (likely ~20 claims with multiple independents) should be confirmed against the printed claims before any § 102 chart is filed.

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3. Cited references — verified front-page list

3.1 U.S. Patent Documents (dates as printed on the 11015956 front page)

3.2 Foreign Patent Documents

3.3 Other cited material

• A reference listed as "Delory." appears in the OCR of the front page among the cited items; I could not confirm whether this is a non-patent-literature citation or an inventor/assignee string. Unverified — do not cite without checking the printed front page.

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4. Most relevant references — detail + § 102 analysis

Below are the entries I can actually support with confirmed subject matter. Everything here is a lead requiring an element-by-element comparison against the granted claims; none of these has been adjudicated as anticipatory to my knowledge.

4.1 US 2014/0341465 A1 — Li et al., "Real-time pose estimation system using inertial and feature measurements," pub. 2014-11-20

• Subject matter (verified): hybrid visual-inertial estimator; propagates state vector/covariance using IMU, processes camera feature measurements via MSCKF / EKF variants, performs a Mahalanobis gating test, updates state with residual + Jacobian.
• Why it matters: This is the single most 11015956-adjacent citation. It discloses (a) fusing different sensor types (camera + IMU), (b) Kalman filtering (including EKF-type), and (c) the exact Mahalanobis statistic the subject patent discloses for discrepancy detection.
• § 102 posture: Publication (2014-11-20) post-dates the 2014-08-15 priority, so it is not § 102(a)(1) art. It is potentially § 102(a)(2) art if and only if its U.S. application was effectively filed before 2014-08-15 (and it names a different inventor). If that predicate holds, it is a candidate to anticipate Bucket B (select reference frame → detect discrepancy → correct) and to render Bucket D obvious together with a calibration reference. If the effective filing date is not earlier, it drops out entirely and is usable only as background/§ 103 evidence.

4.2 US 8,305,430 B2 — Oskiper et al., "System and method for multi-camera visual odometry," 2012-11

• Subject matter: multi-camera (stereo rig) visual odometry, i.e., extrinsic relationship between multiple cameras estimated during operation.
• § 102 posture: Granted 2012-11, well before the 2014-08-15 priority → squarely § 102(a)(1)/(a)(2) art. Strongest candidate for Bucket C's "predicted spatial relationship between at least two sensors" and for the multi-camera aspects. Anticipation of the UAV-specific limitations (in-flight, different sensor types) is doubtful, so more likely § 103.

4.3 US 7,991,550 B2 (Zeng, 2011-08) + US 2008/0300787 A1 (Zeng, 2008-12) + US 9,128,185 B2 (Zeng, 2015-09)

• Subject matter (verified for the 2008/0300787 title): "Method and apparatus for on-vehicle calibration and orientation of object-tracking systems" — a family directed to calibrating/aligning sensors on a vehicle and determining orientation.
• § 102 posture: The 2008 and 2011 members pre-date the priority → § 102(a)(1) art and are the best "calibration-of-onboard-sensors" candidates. They address Buckets A and B conceptually. The 2015 member (US 9,128,185) is post-priority and only matters via § 102(a)(2) if effectively filed earlier — verify the priority chain. Anticipation is unlikely to reach the UAV/in-flight limitations; § 103 is the realistic theory.

4.4 US 8,543,266 B2 (Li) 2013-09 and US 8,483,960 B2 (Li) 2013-07

• Both are pre-priority granted patents in vision/INS navigation and multi-sensor/vehicle control respectively.
• § 102 posture: Available as § 102(a)(1) art. Their utility is against Bucket A's "plurality of sensors of different types … determining subsequent spatial configuration," but the subject patent's in-flight + adjustment of sensor data limitations are likely missing → § 103.

4.5 US 6,285,959 B1 (Greer, 2001-09, G01B 11/002)

• Optical/vision calibration (per class). Pre-priority → § 102(a)(1) art; relevant to Bucket B estimate-then-adjust logic, but far afield from UAV sensor fusion. Background/§ 103.

4.6 US 2002/0198656 A1 (Ford, 2002-12) and US 2004/0150557 A1 (Ford, 2004-08)

• GPS/INS integration and correlation. Pre-priority → § 102(a)(1) art. Relevant to Bucket B's "reference coordinate system" and cross-sensor discrepancy detection. § 103 candidate.

4.7 US 2005/0060092 A1 (Hablani, 2005-03) and US 2007/0023579 A1 (Wang, 2007-02)

• Spacecraft attitude/navigation with Kalman filtering (per classes B64G). Pre-priority → § 102(a)(1) art. Relevant background for the Kalman-filter limitations in Buckets A/D; the cited patent's heavy reliance on Kalman filters means these are plausible § 103 combinators, but not anticipatory for a UAV sensor-calibration claim.

4.8 US 2009/0299494 A1 (Kahn, 2009-12, G05B 13/04) and US 2008/0215204 A1 (Roy, 2008-09, G05D 1/0044)

• Adaptive control / autonomous-vehicle control. Pre-priority § 102(a)(1) art. Background for "processor adjusts data in real time" — likely § 103 only.

4.9 Chinese/KR/JP family (CN 102607592; CN 103033185; CN 103810701; CN 103914065; CN 201262709 Y; KR 101340158 B1; KR 2013-00798881; JP 2003-329510; JP 2013-144539; JP 2016-540211; CA 2782275; EP 2578995)

• These appear to be calibration/sensor-fusion references in the same field. All except JP 2016-540211 pre-date the priority (subject to confirming the exact dates) → § 102(a)(1) art usable as prior printed publications; JP 2016-540211 is post-priority and needs a § 102(a)(2) effective-filing check. I could not verify individual titles/abstracts for these, so I am not asserting any specific anticipation theory.

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5. Bottom line

1. No single cited reference appears to be a clean § 102 anticipation of the full claim set as I read the Summary-level claims — the asserted novelty sits in the combination of (i) different sensor types on a UAV, (ii) in-flight detection of a relative spatial configuration change, and (iii) adjusting the sensor data based on it.
2. The strongest § 102(a)(2) candidate is US 2014/0341465 A1 (Li et al.), but only if its effective filing date precedes 2014-08-15 — verify that first; otherwise it is § 103/background only.
3. The strongest § 102(a)(1) candidates are the pre-2014 references addressing on-vehicle sensor calibration (US 7,991,550 / US 2008/0300787 / US 9,128,185 family) and multi-camera extrinsic estimation (US 8,305,430 B2).
4. The realistic invalidity theory for this patent is § 103: e.g., a multi-camera/vision-calibration reference (Oskiper) combined with a UAV sensor-fusion reference (Li 2013/2014) and an on-vehicle calibration reference (Zeng).

6. What I could not do (so you can close the gap)

• I could not run an authenticated USPTO query (PatentCenter / PTAB / Global Dossier) — only public web search was available.
• I could not verify the ~20 references marked INFERRED (I gave only the year implied by their publication-number series).
• I could not obtain the literal granted claim text of US 11,015,956; the § 102/§ 103 mappings above are keyed to the patent's Summary-level aspects, not to verbatim claim language.

Recommended next steps: pull the printed front page (US11015956.pdf) for the authoritative citation list and dates, pull the granted claims from PatentCenter, then build element-by-element charts for US 2014/0341465 A1, US 8,305,430 B2, US 7,991,550 B2, US 2008/0300787 A1, and US 9,128,185 B2.

Sources used: https://patentimages.storage.googleapis.com/98/8a/43/4d97a32bc70dd0/US11015956.pdf; https://pubchem.ncbi.nlm.nih.gov/patent/US-11015956-B2; https://patents.google.com/patent/US20140341465A1/en; https://patents.google.com/patent/US8305430; https://patents.google.com/patent/US20080300787.

I'll start by trying to retrieve the actual prior-art citations for this patent, since the page text provided to me includes prior-art keywords and a prior-art date but not a reference list.

Let me pull the detailed front-page reference list and the key cited references.

Preliminary caveat: what "the Prior Art section" actually gave us

The page text supplied to me for US 11,015,956 contains only the prior-art keywords ("sensors, spatial, relative, sensor, uav") and the prior-art date (2014‑08‑15) — it does not contain the rendered "Prior Art," "Similar Documents," or "References Cited" tables. Rather than fabricate that list, I reconstructed the face-of-patent reference list from the patent PDF front page and third-party databases, and I flag below where a document's content is not verified. Everything else is grounded in the patent text you supplied, which I treat as authoritative.

Sources used: patent page, granted PDF front page, PubChem citation list, US 2008/0300787 A1 / US 7,991,550 B2 (Zeng), Zeng claims/prosecution detail, US 8,305,430 "multi-camera visual odometry" cited-by page.

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1. Governing law and effective date

Priority is 2014‑08‑15 (continuation of PCT/CN2014/084502). This is a post-AIA application, so AIA § 103 applies with the Graham v. John Deere / KSR framework: scope and content of the prior art, differences from the claims, PHOSITA level, and secondary considerations. Critically, art must predate 08‑15‑2014 under § 102(a)(1) (publication/use) or qualify under § 102(a)(2) via an earlier effective filing date, regardless of its publication date.

That last point matters: one examiner-cited reference visible in the grant text is US 2015/0212391 A1 ("Waibel," 7/2015). Its publication date postdates the priority date, so it is only available as § 102(a)(2) art if its effective filing date precedes 08‑15‑2014. I have not verified its disclosure or effective filing date — it should be checked before relying on it.

Also note two same-assignee documents that are not prior art but are useful context: US 10,565,732 ("Sensor fusion using inertial and image sensors," priority PCT/CN2015/079639, 2015‑05‑23) and US 11,822,353 (later continuation). Their near-identical extrinsic-calibration narrative shows the concepts here were being pursued across the portfolio. US10565732 PDF, US11822353 PDF.

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2. Claim architecture (the "families")

The grant has 18 claims. I do not have verbatim granted claim text, so I analyze the four method/apparatus concept pairs recited in the Summary, which the granted independent claims track:

Dependents add: EKF/UKF; on-board vs. off-board processor; Kalman-based determination of the subsequent configuration; vision/image data adjustment; Mahalanobis-distance discrepancy detection (thresholds 1–20 listed in the spec); time/distance recalibration frequencies.

The specification is unusually explicit about the motivation for each recited feature, which is helpful to a § 103 case: extrinsic parameters change "with a higher frequency" than intrinsic due to "shifting during landing and take-off… vibration, and thermal drift," and parallel Kalman filters "increase the scalability… increase the speed of the response while decreasing the computing resources" (patent text, supplied).

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3. Element-by-element grounding in the cited art

3.1 US 7,991,550 B2 / US 2008/0300787 A1 — Zeng (GM) — verified

This is the closest cited reference and is the natural primary reference. Verified disclosures:

• Multiple, different-type sensors on a common moving platform: object-locating sensors comprising short-range radar, long-range radar, forward-vision, plus LIDAR and ultrasonic — explicitly "different types."
• Initial spatial configuration: sensors are "typically calibrated during the vehicle assembly process"; "establishing initial values for the alignments of each of the object-locating sensors relative to a coordinate system for the vehicle."
• Drift during operation: "sensor orientation and signal output may drift during the life of the sensor… measurements become skewed"; with multiple sensors "outputs between the sensors become skewed."
• On-line, automatic detection + correction during ongoing operation: "automatically perform on-line fine alignment"; algorithm loop cycles "each 3, 6.25, 15, 25 and 100 milliseconds during ongoing engine and vehicle operation."
• Reference-coordinate-system transformation: transform a target from sensor (u,v) frame into vehicle (x,y) frame via r = Rq + r₀; then incremental corrections R' = δR·R, r'₀ = r₀ + δr₀ — i.e., computing a subsequent/updated spatial relationship.
• Discrepancy detection against a predicted relationship: matched pairs {(r_fi, r_ai)} between the fused (predicted) object map and each sensor-observed map; minimizing χ²; incremental rotation δψ and translation δr₀ as the "correction β."
• Adjusting data of each sensor based on the updated configuration: "Each object map is compensated based on each sensor's position (R and r₀)."
• Kalman filter and covariance matrix: the DAC module "further includes a Kalman filter 24a"; registration uses "a sensor data covariance matrix"; range-weighted least squares.

Gap vs. F1: no UAV, and the registration error is minimized against a tracked external target trajectory, not from platform self-motion.

3.2 US 8,305,430 B2 — Oskiper et al. ("System and method for multi-camera visual odometry") — partially verified

Verified as existing and as having US 11,015,956 listed among its citing documents (source). Multi-camera visual odometry requires exactly the inter-camera and camera-to-inertial extrinsic relationships the patent's spec formulates (stereo projections P = K[R T]; hand-eye AX = XB). Its specific disclosure is not verified here, but analytically it is the type of reference that fills the "self-motion in lieu of an external target" gap in Zeng for the F1/F2 families, and it supplies a reason to adjust image data.

3.3 US 8,543,266 B2 (Li) and US 8,483,960 B2 (Li) — content not verified

Both are cited on the face. Given the titles/assignee context, they belong to the UAV-autonomy/sensor-fusion art and supply the "coupled to a UAV" element for combining with 3.1 (the specification itself notes Li's patents are the assignee's own earlier work). I flag their contents as unverified; the combination argument below must be re-run against actual text.

3.4 Delory, "Design and analysis of a navigation system using the federated filter," AFIT Thesis, Dec. 1995 — cited on the face

A federated Kalman filter architecture divides one system into local filters, each processing a subset of measurements relative to a reference, whose outputs are combined by a master filter. This is directly probative of F3 (subset grouping) and, at least in part, F4. (The patent's own spec describes one-Kalman-filter-per-subset with a subsequent combination step and touts parallel benefits.)

3.5 Remaining face-cited documents — not verified

US 5,506,794 (Lange); US 5,892,690 (Boatman); US 6,285,959 (Greer); US 6,405,135 (Adriany); US 6,577,976 (Hoff); US 8,001,860 (Preston); US 8,364,334 (Smitherman); US 9,128,185 (Zeng); JP 2003-329510; CA 2782275; CN 201262709 Y; CN 102607592; CN 103033185; CN 103810701; CN 103914065; EP 2578995; KR 20130079881; US 2015/0212391 (Waibel). Several (notably the CN camera/IMU-calibration filings and the two Zeng-family documents) are plausibly on-point, but I will not assert their disclosures without verification.

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4. Obviousness combinations

Combination A (strongest) — Zeng '550 as primary + UAV multi-sensor art (Li '266 / '960, or the '787/'391 family) as secondary

Claims reached: the F1 family and most of its dependents (Kalman determination of the subsequent configuration; on-board processor; vision-data adjustment).

Motivation / KSR rationales:

1. Same field of endeavor and same problem — multi-sensor registration to keep a fused data product trustworthy when sensor orientation drifts. That defeats a non-analogous-art attack.
2. Known technique applied to a known device with predictable results (KSR): on-line registration used to improve a multi-sensor vehicle would improve a multi-sensor UAV in the same way.
3. The patent supplies its own motivation: the spec states drift is caused by "shifting during landing and take-off… vibration, and thermal drift," and that remote (ground-link) calibration is infeasible once the UAV is out of range — i.e., the UAV context increases the need for what Zeng already does.
4. Substitution of one moving platform for another is the classic "simple substitution of a known element for a known element."

Rebuttal to expect, and response: Applicant will argue Zeng requires a tracked external target as ground truth, whereas the claims use on-board cross-sensor data with no external target. That is a real difference for parts of F2 ("discrepancy in the sensor data between the plurality of sensors"). It is overcome by adding a visual-odometry/hand-eye reference (Oskiper '430 or verified camera–IMU calibration art) teaching that the platform's own motion, observed by two different sensors, yields the relative-pose residual — which is exactly the residual Zeng computes by another route.

Combination B — Zeng '550 + Oskiper '430 (multi-camera visual odometry) [+ camera–IMU calibration art]

Claims reached: F2 (reference coordinate system; predicted relationship; discrepancy; actual configuration) and the dependent "adjusting image data captured by a vision sensor."

• Oskiper-type art supplies: extrinsic estimation among multiple cameras/IMU from motion correspondences; the standard projection P = K[R T] and the hand-eye AX = XB formulation that the patent itself reproduces verbatim in the spec, including the n ≥ 3 uniqueness requirement. A PHOSITA reading the patent's own math knows these are textbook techniques (Zhang stereo calibration; hand-eye calibration), which itself supports treating the F2 method steps as conventional.
• Motivation: vision-inertial fusion requires known extrinsics; extrinisics drift in flight → the same reason Zeng recalibrates.

Combination C — Zeng '550 (or A) + Delory 1995 (federated filter)

Claims reached: F3 and F4 ("grouping… into a plurality of subsets," "at least one Kalman filter per subset," parallel multi-filter determination).

• Delory teaches decomposing estimation into local filters over measurement subsets with a reference, then combining — the F3/F4 architecture.
• Motivation is threefold and is largely admitted in the patent: scalability/expandability, increased response speed, and reduced computing resources. Independent corroboration: the claimed benefit of parallel/federated filtering is a recognized engineering result, making this a "use of a known technique to improve similar devices in the same way."

Combination D — Zeng '550 + any variance/covariance-based outlier test (Mahalanobis distance)

The dependent recitation of Mahalanobis distance with a threshold is the straightforward statistical extension of Zeng's covariance-weighted χ²/least-squares residual (W = diag{w₁…w_N}; range-dependent weighting; resetting prior registration when a lateral offset exceeds a threshold). Using a covariance-normalized distance as the drift detector, and merging F1+F2 with the subset architecture, is a predictable combination of prior-art elements under KSR.

Secondary considerations

No evidence of unexpected results is apparent on the face of the patent. Any nexus argument based on UAV-specific performance must contend with the fact that the claimed improvements are the known benefits of on-line registration and parallel filtering, not new ones.

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5. Where the obviousness case is weaker (be candid)

1. F4's "at least two subsets have different reference sensors." Federated filtering typically uses one common reference (the master/global frame). Shifting which sensor is the reference from subset to subset is a specific configuration that may not be taught. If no cited reference discloses it and no evidence of record shows it was a known design choice, F4 has the best non-obviousness position.
2. No-external-target recalibration. Zeng's trajectory-based ground truth is genuinely different from the claimed inter-sensor discrepancy. Combination A alone may be insufficient for F2 absent a self-motion reference.
3. Reference = IMU frame. If a claim requires the reference coordinate system to be the inertial sensor's frame, the record needs an explicit teaching; the specification asserts this only as one option ("may be an inertial measuring unit").
4. Verification gaps. My analysis rests on Zeng (verified) and Delory (title/abstract-level only); the CN/JP/KR references and US 2015/0212391 (Waibel) are cited but unverified, and several (Waibel in particular) may not even qualify as § 102 art given its July 2015 publication date.

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6. Bottom line

• Broad in-flight-calibration claims (F1, and apparatus counterpart): likely obvious over US 7,991,550 (Zeng) in view of UAV multi-sensor art (the Li patents cited on the face, or the '391/'787 family), with the patent's own admission of vibration/thermal drift and out-of-range operations supplying the motivation.
• Reference-coordinate-system / discrepancy-detection claims (F2): obvious over Zeng + a visual-odometry/camera–IMU calibration reference (Oskiper '430 or verified hand-eye-calibration art); the patent's spec reproduces the standard AX = XB math, which undercuts any argument that these steps were non-routine.
• Subset / parallel-Kalman-filter claims (F3): obvious over Zeng (or A) + Delory's federated filter, with the motivation of scalability and reduced computation stated on the patent's own face.
• Different-reference-sensor-per-subset claims (F4): the strongest candidate to survive unless a reference expressly teaches varying the reference sensor across subsets.
• Dependent statistical/Kalman-type/processor-placement claims: obvious as routine design choices (Mahalanobis distance; EKF vs. UKF; on-board vs. off-board).

Before relying on this opinion, verify: (i) the literal granted claim text (18 claims) — I analyzed the Summary's concept families, not granted wording; (ii) the disclosures and effective filing dates of US 2015/0212391 (Waibel), the CN camera/IMU references, and the two Li patents; (iii) whether US 8,305,430 discloses the specific inter-sensor residual computation needed for F2.