US 6850557

I'll search for authoritative information on this patent, including any litigation.

I have the specification but not the claims text. Let me retrieve the claims and check for any 2026 Federal Circuit activity.

US 6,850,557 B1 — Analyst Summary

Caveat up front: I was able to confirm bibliographic data and litigation from public sources, but I could not retrieve the verbatim, numbered claim set of US 6,850,557 from an authoritative source in this session. The plain-language claim overview below is reconstructed from the patent's own "Summary of the Invention" and abstract (which mirror the claim architecture), and I flag where I am inferring rather than quoting. Treat the claim descriptions as provisional pending a check against the official USPTO/Google Patents claims section.

Bibliographic data (confirmed)

Assignment chain shown on the record: Conexant Systems (2000) → SiRF Technology Holdings (2002) → SiRF Technology (2002) → CSR Technology Inc. (change of name, 2011) → Qualcomm Incorporated (2014).

Abstract (as published, verbatim gist)

A signal detector employs a coherent accumulation system that coherently combines the correlation results derived from segments of samples of a received signal. The segments may have non-uniform lengths and may have been obtained over different and non-overlapping time periods, during sampling windows of arbitrary length and at arbitrary times. The results of processing the segments are successively combined in a coherent manner (separate magnitude and phase accumulation) until a threshold signal-to-noise ratio (SNR) is achieved. Coherent integration is enabled by introducing a carrier phase offset as well as a code phase offset, so that different segments are aligned in carrier phase as well as code phase. In one implementation the signal detector is used in a GPS receiver.
Source: https://patents.google.com/patent/US6850557/en

Plain-language overview of the independent claims (reconstructed — verify against the official claim text)

The disclosure describes a two-part architecture: a correlator (which receives hypotheses — code, code phase, Doppler) and a combiner (e.g., an integrator). On that architecture, the independent claims appear to fall into these families:

1. Apparatus / "signal detector" claim (system). A receiver acquires a first segment of a signal and a second segment of the same signal during different, non-contiguous time periods (the signal is a signal of interest perturbed by noise/pseudo-noise, e.g., a PN-coded carrier). A correlator derives first correlation data for the first segment against a hypothesis, applies/imposes a carrier phase offset on the second segment so the second segment's carrier phase corresponds to that of the first, and derives second correlation data for the phase-shifted second segment. A combiner coherently combines the first and second correlation data (real parts with real parts, imaginary with imaginary) to yield cumulative correlation data used to detect the signal or a parameter of it (e.g., presence, code phase).

2. Method claim. The corresponding process: receive disjoint/non-uniform segments; generate hypotheses; impose a carrier phase offset to align a later segment to an earlier one; derive correlation data for each; apply a code (Doppler) phase offset so the code phases are alignable despite the actual code phases being unknown; coherently accumulate the segments until a threshold SNR permits detection.

3. Likely additional independent claims (consistent with the "Related methods of operation and computer readable media are also provided" statement): a computer-readable-medium claim embodying the method, and possibly a GPS-receiver claim reciting RF receiver, offset-measurement circuitry, PN code generator, signal detector, and GPS processor — but I have not verified these verbatim.

Notably, the hallmark limitation is both a carrier phase offset and a code phase offset applied so that non-uniform, disjoint captures can be coherently (not merely non-coherently) accumulated — the patent expressly says one may be practiced without the other, but the claimed combination is the point of novelty.

Litigation / CAFC status

• No 2026 Federal Circuit docket involving 6,850,557 was found. Given that the patent's term expired April 18, 2020, active 2026 appellate activity is unlikely, and I am stating explicitly that I could not confirm any.
• The known assertion: SiRF Technology, Inc. v. Global Locate, Inc. and Innovation Sales Southern California, filed December 2006 in the U.S. District Court for the Central District of California, asserting U.S. Patent Nos. 7,091,904; 7,043,363; 6,850,557; and 6,636,178.
  • Source: https://www.electronicdesign.com/markets/automotive/article/21797306/sirf-sues-global-locate-for-patent-infringement
• Do not conflate this with the Federal Circuit's SiRF Technology, Inc. v. International Trade Commission (No. 2009-1262, decided April 12, 2010). That appeal arose from ITC Inv. No. 337-TA-602 and concerned Global Locate/Broadcom's patents (the '801, '346, '000, '651, '187, and '080 patents) — not 6,850,557. See https://cafc.uscourts.gov/opinions-orders/09-1262.pdf
• The Google Patents family page notes an entry in a third-party litigation dataset (Darts-IP family 24199621), consistent with the SiRF/Global Locate disputes, but I could not independently open that dataset.

Related patents (distinct — do not attribute their claims to '557)

• US 6,636,178 — "Signal detector employing correlation analysis of non-uniform and disjoint sample segments" (same family/inventor lineage; its claim 1 recites combining based on a parameter difference rather than the carrier-phase-offset architecture of '557).
• US 6,577,271 — "Signal detector employing coherent integration."

If you need the verbatim independent claims quoted with exact claim numbers and dependencies, say so and I'll flag it as the one remaining gap — that text should be pulled directly from the USPTO PatentCenter/Google Patents claims section rather than inferred.

I'll research litigation involving US Patent 6850557 across patent litigation databases.

Let me search more targeted litigation sources.

I found a strong lead. Let me dig deeper into the SiRF v. Global Locate case and search for any other litigation.

I've reached my search budget. Here is what I was able to verify, with clear flags on what remains unconfirmed.

Summary

US Patent 6,850,557 ("Signal detector and method employing a coherent accumulation system to correlate non-uniform and disjoint sample segments")

• Inventor: Steven A. Gronemeyer
• Priority/filing date: April 18, 2000
• Granted: February 1, 2005
• Original assignee: SiRF Technology, Inc. (assigned from Conexant Systems, Inc. in 2000)
• Later chain of title: SiRF Technology Holdings → SiRF Technology, Inc. → CSR Technology Inc. → Qualcomm Incorporated (assignment recorded 2024)
• Status: Expired – Lifetime (anticipated expiration April 18, 2020)

Known litigation

1. SiRF Technology, Inc. v. Global Locate (and its distributors)

Source: A December 21, 2006 report (unitalen.com, http://unitalen.com/html/report/16113197-1.htm) states that SiRF Technology filed a patent infringement suit against Global Locate and its resellers in the U.S. District Court for the Central District of California, asserting the four GPS patents listed above, including US 6,850,557, and seeking damages plus a preliminary/injunctive remedy.

Corroborating indicator: the Google Patents record for US6850557 itself carries a "Family has litigation / First worldwide family litigation filed" notation, linking to a Darts-IP family page (family=24199621), which confirms that litigation on the family exists — consistent with the SiRF case above.

Important caveats — what I could NOT confirm

1. Case number and exact filing date for SiRF v. Global Locate were not returned in my searches; only the approximate date (December 2006) and court (C.D. Cal.) are supported.
2. Outcome. SiRF and Global Locate were litigants in multiple overlapping suits (including a parallel ITC action and a later Broadcom/Global Locate dispute). I did not retrieve a docket, settlement, dismissal, or judgment specifically resolving the '557 patent claims, so I cannot state the disposition.
3. No later/other cases were found. I found no evidence that the '557 patent was asserted after the SiRF campaign, nor any PTAB/IPR challenges tied to it. The patent expired in 2020, so post-2020 assertion is unlikely.
4. Vetting limits. My attempts to query PACER, the Unified Patents litigation portal, and CourtListener directly for this exact number were cut off by the search-step limit. A definitive docket-level confirmation should be run against PACER (C.D. Cal., 2006–2008) and the Darts-IP family page cited on the Google Patents record.

I did not find any litigation involving similar-but-distinct numbers (e.g., US 6,885,055; US 7,068,557; US 6,895,557), and I have deliberately excluded those from the list above, per your instruction.

Bottom line: The only litigation I can substantiate for US 6,850,557 is the ~December 2006 SiRF Technology v. Global Locate action in the Central District of California, in which the '557 patent was one of four asserted GPS patents. Case number and final disposition remain unverified.

I'll start by checking the structured proceedings block and then attempt to corroborate with web search.

Proceedings overview

Total AIA trial proceedings on US 6,850,557: 0. The USPTO Open Data Portal returns no IPR, PGR, or CBM proceeding for this patent, and independent web checks (patent-number searches, petitioner-oriented searches, and litigation-history searches) surfaced no petition, institution decision, Final Written Decision, or PTAB appeal for the '557 patent as of 2026-09-29. Because the count is zero, there is no active / invalidated / sustained / settled / denied breakdown to report — the breakdown is simply 0 active, 0 invalidated, 0 sustained, 0 settled, 0 institution-denied.

Defensive posture: "no PTAB activity on file" — the patent has never been tested at the Board. It has not been "hardened" by surviving IPRs (that would be a misread of the record), and it has not been narrowed or killed either. The more consequential facts for a defendant today are (a) the '557 patent's anticipated expiration on 2020-04-18 with legal status "Expired - Lifetime" (Google Patents, https://patents.google.com/patent/US6850557/en), and (b) the only real adversarial history on this patent is SiRF asserting it as plaintiff, not anyone challenging it.

Closest thing to a proceeding on the '557 patent

There is no ### {PROCEEDING_NUMBER} section to populate because no AIA proceeding exists. For completeness, the non-PTAB adversarial history that shows up under the patent's litigation family is:

SiRF Technology, Inc. v. Global Locate, Inc. (district court / ITC — not a PTAB proceeding)

• Type: Not an AIA trial. District court infringement action (C.D. Cal.) and companion ITC § 337 investigations.
• Filed: SiRF's complaint naming the '557 patent was filed in December 2006 (reported 2006-12-18/2006-12-21) in the U.S. District Court for the Central District of California against Global Locate and its distributor Innovation Sales Southern California. Reported asserted patents: 7,091,904; 7,043,363; 6,850,557; and 6,636,178. Source: https://www.electronicdesign.com/markets/automotive/article/21797306/sirf-sues-global-locate-for-patent-infringement
• Status: No PTAB status (not an agency trial).
• Judge panel: N/A (Article III court / ALJ).
• Grounds: Infringement, not validity challenge. SiRF sought injunctive relief and monetary damages.
• Related proceedings: ITC Inv. No. 337-TA-596 ("Certain GPS Chips, Associated Software and Systems, and Products Containing Same," SiRF as complainant) and the mirror-image 337-TA-602 (Global Locate as complainant); global litigation family flagged on the Google Patents page (Darts-IP family 24199621) is this dispute, not a PTAB family.
• Appeal: Fed. Cir. 2009-1262, SiRF Tech., Inc. v. ITC, aff'g the ITC's exclusion/cease-and-desist orders on the Global Locate/Broadcom patents-in-suit (opinion: http://cafc.uscourts.gov/opinions-orders/09-1262.pdf). Note: the '557 patent was asserted by SiRF in the district court case; the ITC appeals turned on the Global Locate patents, so do not attribute any '557 validity holding to 2009-1262.
• Defensive value: Establishes that the '557 patent was a sword wielded by SiRF/CSR, not a patent that has been adjudicated. There is no invalidity record to lean on.

Strategic summary

Claim landscape: untested, not canceled. No claim of 6,850,557 has ever been canceled, confirmed, or construed by the PTAB — the entire claim set (including the independent claims directed to a signal detector with a correlator imposing a carrier phase offset on a later segment plus a combiner that coherently combines first and second correlation data) is UNTESTED on the AIA-trial record. There is no narrowing certificate, no certificate of correction driven by an IPR, and no surviving-claims-after-IPR list, because no IPR exists. Anyone telling you the patent "survived two IPRs" or "lost claims 1–5 to a troll-filed IPR" is misinformed. On the litigation side, the only recorded assertion is the 2006 SiRF→Global Locate action plus the parallel ITC investigations.

Estoppel landscape: none, but also little to estop. Because no IPR/PGR/CBM was ever instituted, no party is subject to 35 U.S.C. § 315(e)(2) estoppel on this patent — there is no petitioner-side bar on prior-art grounds, and no IPR estoppel to argue about in a district court case. That cuts both ways: a defendant today faces no truncation of its own invalidity case, but it also cannot point to any Board findings. Practically, the more useful levers are: (i) the patent expired 2020-04-18, so injunctive relief is off the table and § 286's six-year damages lookback (measured from a complaint filed today, 2026-09-29) reaches back only to 2020-09-29 — entirely after expiration; (ii) § 282 invalidity defenses and the on-sale/public-use/prior-art record from the SiRF–Global Locate era remain fully available in district court, where the § 311(b) patent/printed-publication limit of IPR does not apply; and (iii) ex parte reexamination — which saw record filings in 2025 (726 requests) — is available for the patent/printed-publication art, subject again to the same § 286 reality check on recovery.

Pattern signals. No repeat-petitioner pattern (no petitioner at all). No PTAB appeal history, because there is no FWD to appeal. No defensive aggregator (Unified Patents or similar) appears anywhere in the '557 record — the Unified Patents material that surfaces in searches is generic policy commentary, not a petition against this patent. The Google Patents "Family has litigation" flag is the Darts-IP litigation family from the SiRF/Broadcom–Global Locate GPS wars, not an AIA family. Ownership has moved through Sirf Technology → CSR Technology → Qualcomm Incorporated (assignment recorded 2024-10-14), so any future assertion would come from Qualcomm, an operating company rather than an NPE — which historically correlates with a lower IPR institution rate and, under the USPTO's 2025–2026 "settled expectations"/discretionary-denial posture (see https://thenaplesroundtable.org/wp-content/uploads/formidable/29/2025-in-Review-Unified-Patents.pdf), would make institution on a 2000-priority patent even harder.

Recommended next steps

• Do not represent that PTAB proceedings exist. For any opinion letter, IPR estoppel analysis, or § 315(b) timing memo, the correct statement is: no AIA trial proceeding has ever been filed or instituted on US 6,850,557 (verified against the USPTO ODP "PTAB proceedings on file" block and web searches conducted 2026-09-29).
• Re-run the check against PTAB E2E / the PTAB "Patent Trial and Appeal Board" search before filing anything, since the ODP ingest lags and a recently-filed petition would not yet appear: USPTO Patent Trial and Appeal Board End-to-End (PTAB E2E) at https://ptacts.uspto.gov/ptab-web/ and the Patent Center record at https://patentcenter.uspto.gov. If a petition exists, the § 315(b) one-year clock, the six-month institution deadline, and the statutory one-year trial deadline from institution would be the milestones to calendar; none of those is running today.
• Lead with the expiration, not with an IPR threat. The strongest defensive posture for a defendant asserted against the '557 patent is: expired 2020-04-18; no injunctive exposure; § 286 lookback from a 2026 complaint reaches only post-expiration conduct. Then layer § 282 district court invalidity using the substantial prior-art record developed in the SiRF–Global Locate/Broadcom GPS litigation, plus the 2000 priority date and the '557 prosecution history.
• If the client wants an agency bite at the apple, the practical option is ex parte reexamination (no § 315(b) bar, no estoppel, no discretionary-denial "settled expectations" gate in the same way), not IPR — but weigh the cost against the near-zero damages exposure of an expired patent.
• Flag any demand letter that cites claim numbers as if they were adjudicated. No claim of this patent has been canceled by the Board; a demand letter implying otherwise is an overstatement you can call out.

Verification note / limitation: within this task's search budget I could not open the PTAB E2E docket or CourtListener docket directly; the conclusion rests on the structured ODP block (authoritative for AIA trials) plus patent-number and litigation-history web searches that returned no petition. Search hits for "6850557" on third-party petition-download pages (e.g., unrelated Ambato Media filings) were false positives on the number string and do not evidence a proceeding on this patent.

I'll research the assignment record for US 6850557, starting with the USPTO Assignment Center data and cross-references.

Assignment Reconstruction — US 6,850,557 B1

Data-gap notice (read first). The USPTO Assignment Center could not be queried live in this session (my Assignment Search / PEDS queries returned no usable records, and no third-party mirror surfaced reel/frame or correspondent data). The timeline below is therefore reconstructed from the Google Patents "Legal Events / reassignment" record for US 6,850,557, which mirrors the underlying USPTO assignment entries but strips reel/frame numbers and the correspondent of record. I have left those fields explicitly marked [not retrieved] rather than guessing. Google's event dates are recording dates; execution dates are not separately exposed by that source and are also marked [not retrieved] unless otherwise evident.

Source of record for this reconstruction: https://patents.google.com/patent/US6850557/en (Legal Events). Verification entry point: https://assignment.uspto.gov/patent/index.html and https://assignmentcenter.uspto.gov/ (search by patent number 6850557).

Inventors

Unusual-pattern notes:

• Single-inventor patent. No co-inventor inventory to test for a "mass inventor departure."
• No inventor-departure signal. The classic red flag ("all inventors gone within 12 months of filing") is not present. The rights left the original employer (Conexant) roughly two years after filing — and did so as a corporate transfer of the GPS business unit, not as an inventor event. You cannot read a personnel exodus from this record.
• Filing-stage assignment, not a post-issuance one. The inventor assigned to Conexant at filing (2000-04-18), consistent with an employed-inventor obligation. He is not listed as an assignor on any subsequent link.

⚠️ Cross-reference flag: the previously generated summary characterized Gronemeyer's affiliation loosely. The record here is unambiguous — at filing he was a Conexant assignor, and “SiRF” is the entity that acquired the rights later (2002), not his 2000 employer.

Original assignee

• Entity named on the issued patent (2005-02-01): SiRF Technology, Inc. (Google Patents records the "Original Assignee" as Sirf Technology Inc; the application itself was originally assigned to Conexant Systems, Inc. in 2000).
• Primary line of business: GPS/GNSS receiver chipset and software design (fabless semiconductor / IP licensing), then part of the SiRF Technology Holdings, Inc. public group (Nasdaq: SIRF).
• Product embodying the claims: Yes. SiRF shipped commercial GPS chipsets (the "SiRFstar" family) and the assertion history confirms its patents were asserted against a direct GPS-chip competitor (Global Locate). The Conexant lineage chips cited inside the patent ("Magna," "Scorpio," "Gemini/Pisces") are hardware implementation examples.
• Current status: The original assignee no longer exists as an independent entity. SiRF Technology Holdings, Inc. was acquired by CSR plc (2009); the U.S. operating/patent entity was renamed CSR Technology Inc. (recorded 2011-12-22); CSR plc was then acquired by Qualcomm Incorporated (2015), with the U.S. patent entity's interest recorded to Qualcomm on 2024-10-14. Conexant Systems (the 2000 assignor) survives as a semiconductor company (now part of the Skyworks portfolio lineage) but divested this GPS subject matter in 2002.

Assignment timeline

All entries below are recorded events per Google Patents Legal Events; execution dates and reel/frame and correspondent are [not retrieved] for every entry (Assignment Center not reachable this session). Conveyance type is taken from the description Google Patents reproduces from the record.

• 2000-04-18 (executed — filing date) / recorded [2000-04-18 per record; exact recording date not retrieved] — Reel [not retrieved]

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST ("see document for details")
  • Assignor: Gronemeyer, Steven A.
  • Assignee: Conexant Systems, Inc.
  • Correspondent: [not retrieved]
  • Context: Initial employed-inventor assignment at filing — the rights were never held by the inventor personally.

• 2002-06-17 (executed [not retrieved]) / recorded 2002-06-17 — Reel [not retrieved]

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: Conexant Systems, Inc.
  • Assignee: SiRF Technology Holdings, Inc.
  • Correspondent: [not retrieved]
  • Context: Acquisition / divestiture — Conexant's GPS subject matter (the "Magna/Scorpio/Gemini-Pisces" line the patent describes) moves to the SiRF group before the patent issues.

• 2002-11-06 (executed [not retrieved]) / recorded 2002-11-06 — Reel [not retrieved]

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: SiRF Technology Holdings, Inc.
  • Assignee: SiRF Technology, Inc.
  • Correspondent: [not retrieved]
  • Context: Internal corporate reorganization — the holding company pushes title down to the U.S. operating company (~4.7 months after the 2002-06-17 link).

• 2011-12-22 (executed [not retrieved]) / recorded 2011-12-22 — Reel [not retrieved]

  • Conveyance: CHANGE OF NAME (not an assignment of interest)
  • Assignor: SiRF Technology, Inc.
  • Assignee: CSR Technology Inc.
  • Correspondent: [not retrieved]
  • Context: Name change only — no new consideration moved; consistent with CSR plc's 2009 acquisition of SiRF and the subsequent U.S. entity rename.

• 2024-10-14 (executed [not retrieved]) / recorded 2024-10-14 — Reel [not retrieved]

  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: CSR Technology Inc.
  • Assignee: Qualcomm Incorporated
  • Correspondent: [not retrieved]
  • Context: Intra-group transfer / confirmatory or corrective assignment. ⚠️ Timing anomaly worth flagging: the CSR→Qualcomm acquisition closed in 2015, yet this interest is recorded in 2024 — nine-plus years later. That pattern (late recording of a "clean-up" assignment) is typical of a confirmatory assignment, a corrective recording, or an internal entity reallocation, but I could not verify the document's nature, execution date, or purpose in this session. Do not treat the 2024 date as the economic transfer date.

⚠️ Contradiction with the previously generated section: the earlier summary's assignment chain stated Qualcomm was recorded in "(2014)". The authoritative source page shows 2024-10-14. The earlier date is wrong; the 2024 recording should be used.

Timeline diagram

timeline
    title Ownership of US 6850557
    2000 : Inventor assigns to Conexant Systems
    2002 : Conexant GPS rights to SiRF Holdings
         : SiRF Holdings to SiRF Technology
    2005 : Patent issues to SiRF Technology
    2006 : SiRF sues Global Locate
    2011 : SiRF renamed CSR Technology
    2020 : Patent term expires
    2024 : CSR assigns to Qualcomm

NPE / troll-pattern signals

Secondary corroboration of the assertion history: the Google Patents family page carries a Darts-IP litigation flag (family 24199621) under "Family has litigation" — consistent with the SiRF/Global Locate actions, but I could not open the Darts-IP dataset to enumerate case numbers.

Verdict

Operating-company assertion.

Justification: the entire recorded chain — Conexant Systems (2000-04-18) → SiRF Technology Holdings (2002-06-17) → SiRF Technology (2002-11-06) → CSR Technology via change of name (2011-12-22) → Qualcomm (2024-10-14) — consists of operating semiconductor companies, with no shell LLC, no NPE-list assignee, no bankruptcy sale, and no defensive aggregator; the only known assertion (SiRF v. Global Locate, filed December 2006, asserting this patent among others) was brought by an operating company in its own name against a direct GPS-chip competitor, and occurred ~4.5 years after title settled, so the pre-litigation-transfer screen is negative. Two caveats keep this from being a "clean" call: (a) the correspondent of record is unretrieved for all five links, so signal #3 remains genuinely unresolved rather than absent; and (b) the 2024-10-14 Qualcomm recording is an unexplained late entry relative to the 2015 CSR acquisition and should be checked for a confirmatory/corrective character. Note finally that the patent's term expired 2020-04-18, so there is no live assertion capacity regardless of the chain.

Verify the underlying recordings here: https://assignment.uspto.gov/patent/index.html (search by patent number 6850557) and https://assignmentcenter.uspto.gov/.

I'll search for the authoritative patent record and its cited prior art.

Let me retrieve the references-cited section specifically, which appears in the patent's front page.

The searches are returning the specification but not the front-page "References Cited" list. Let me target that specifically.

Scope and verification note (read first)

Two honest limitations govern this answer, and I will not paper over them:

1. The verbatim numbered claims of US 6,850,557 B1 were not available in this session (carried over from the prior section). All "claim" references below are to the reconstructed claim families (apparatus / method / CRM), not to quoted claim language.
2. I could not retrieve the official front‑page "References Cited" list (the USPT O/Google Patents (56) block listing examiner‑ and applicant‑cited patents). My several searches returned the specification, family data, and unrelated (56) blocks, but not this patent's own citation table. Do not treat the lists below as the certified (56) record. What I can give you authoritatively is (a) the references the patent expressly cites and incorporates by reference in its own text (these are quoted directly from the authoritative full text supplied), and (b) the patent family / related U.S. patents confirmed by search.

Action item: the true (56) citation table should be pulled from USPTO PatentCenter or the Google Patents "References Cited" panel for US 6,850,557 before any §102 conclusion is relied upon.

A. References cited in the body of US 6,850,557 (authoritative — from the patent text)

The patent incorporates the following by reference. Each is pre‑filing art (all granted before the April 18, 2000 filing date, so §102(b) and/or §102(a)/(e) art as applicable). Titles are quoted from the patent text; grant dates below are reconstructed from my knowledge and should be verified — flag any discrepancy.

Also expressly referenced in the text (not a patent citation, but part of the record): U.S. application Ser. No. 09/145,055, filed Sep. 1, 1998 (parent/reference application for the matched‑filter and signal‑detector details).

Caveat on what these are for '557: most of these are SnapTrack/Krasner‑lineage snapshot‑GPS patents. They disclose non‑coherent snapshot correlation, FFT/fast‑convolution correlation, and communication‑link aiding. They do not disclose the '557 point of novelty — combining disjoint, non‑uniform segments by imposing a carrier phase offset AND a code (Doppler) phase offset and then coherently (complex, phase‑preserving) accumulating across captures. As such they are §103 background/combination art, not §102 anticipation art.

B. Related U.S. patents confirmed by search (distinct from '557 — do not attribute their claims)

These same‑inventor, earlier‑filed patents are the most legally relevant prior art on the record for '557 (potential §102(e)/§103 art, subject to common‑ownership/§103(c) considerations). See https://pubchem.ncbi.nlm.nih.gov/patent/US-[6577271](/patent/6577271)-B1 and https://typeset.io/papers/signal-detector-employing-correlation-analysis-of-non-2oia5hoiq8.

C. §102 anticipation analysis (provisional — see caveats)

Because I lack the verbatim claims, I apply the reconstructed independent‑claim architecture from the prior section. A single reference anticipates under §102 only if it discloses every limitation. The critical limitations are:

• (L1) receive first and second disjoint/non‑uniform segments of a PN‑coded signal acquired during different time periods;
• (L2) correlator derives first correlation data (complex) against a hypothesis;
• (L3) impose a carrier phase offset on the second segment so its carrier phase corresponds to the first;
• (L4) derive second correlation data for the phase‑shifted second segment;
• (L5) coherently combine (real parts with real parts, imaginary with imaginary) to produce cumulative correlation data for detecting the signal or a parameter.

Applying that:

Bottom line: On the reconstructed claim set, no cited reference cleanly anticipates under §102 the claimed combination of (disjoint capture) + (carrier‑phase offset) + (code/Doppler phase offset) + (coherent accumulation). They are properly characterized as §103 obviousness‑type background, with the closest being the applicant's own earlier US 6,577,271 and US 6,304,216 (raising a priority/§102(e)/§103(c) analysis rather than classic anticipation).

D. Explicit caveats and next steps

• Do not represent the §102 conclusions above as final. They rest on a reconstructed claim set. Anticipation requires element‑by‑element correspondence to actual claim language.
• I could not verify the official (56) examiner/applicant‑cited list. The references in §A are cited in the specification; the (56) table may contain additional references I did not retrieve.
• Dates in §A are reconstructed from memory and must be confirmed against the respective front pages.
• Recommended verification path: (1) Google Patents "References Cited"/"Cited By" panels for US6850557; (2) USPTO PatentCenter for the (56) block and the file history (any §103 rejections and the art the examiner actually applied); (3) confirm the parent/continuation relationship to 09/281,741 (US 6,304,216) and 09/145,055, since that controls the effective priority date and the §102(e) analysis for the same‑inventor patents.

If you want, I can attempt one more targeted retrieval of the (56) table and the verbatim claims — flagging that these are the two remaining gaps.

I'll research the prior art landscape for this patent, since the page's "Prior Art" section is limited to keywords. Let me pull the actual references.

Excellent — the PCT search report for this exact application surfaced the actual prior-art citations. Let me characterize those references and try to retrieve the claims.

Obviousness Analysis — US 6,850,557 B1 under 35 U.S.C. § 103

Caveat carried forward. As flagged in the summary section above, I could not retrieve the verbatim, numbered claim set of US 6,850,557 in this session. Everything below is keyed to the claim architecture that is recoverable from the abstract, the "Summary of the Invention," and — decisively — the PCT International Search Report for this application's own PCT counterpart, WO 01/79877 A3, which lists the art the examiner actually applied. If the issued claims differ materially from the PCT claims, the mappings below must be re-run. I flag this as the one open gap.

1. What the "Prior Art" section of this page actually contains

The Google Patents page offers only a keyword-level prior-art summary, not a reference list:

• Prior art keywords: signal, segment, interest, correlation, correlation data
• Prior art date: 2000-04-18
• Classifications: G01S19/23, 19/235, 19/29, 19/30, 19/254, 19/256; H04B1/707; H04L27/0014 etc.

Those keywords are, in effect, a paraphrase of the claim elements ("a segment of a signal … correlation data representative of a correlation … signal of interest"). That is analytically significant: the keyword set itself shows the claims are drawn to generic correlation primitives (a segment, a signal of interest, correlation data), which broadens the reading of the claims and correspondingly enlarges the pool of art that reads on them.

Because the page's prior-art section is thin, I went to the authoritative source: the ISR for WO 01/79877 A3 — the search report for this very application's PCT filing (PCT/IB2001/000636, priority claim to US 09/551,047). It lists:

Sources: WO 01/79877 A3 search report — http://patentimages.storage.googleapis.com/10/75/ac/63c5bc1aad83cc/WO2001079877A3.pdf ; WO 00/14568 — https://patentimages.storage.googleapis.com/1b/e8/f1/18515c604039c2/WO2000014568A1.pdf ; WO 00/14560 — https://worldwide.espacenet.com/patent/search/family/022530232/publication/WO0014560A1 (EP 1112508 B1, AU 6027299 A) ; US 6,044,105 — https://worldwide.espacenet.com/publicationDetails/biblio?CC=US&NR=[6044105A](/patent/6044105A)

Significance of the "X" designation: an X citation is the ISA's statement that the claims "cannot be considered novel or cannot be considered to involve an inventive step when the document is taken alone." The ISA thus already took the position that WO 00/14568 alone reaches the pending claims; the Y references were cited to close any residual gap. That is unusually strong evidence that a § 103 combination exists, because the examiner of record is the one who assembled it.

2. Level of ordinary skill in the art (PHOSITA)

A person of ordinary skill in the art as of April 18, 2000 would have had a B.S. in electrical engineering (or equivalent) and 2–5 years of experience in spread-spectrum/GPS receiver design, including working familiarity with: coherent vs. non-coherent integration and "squaring loss"; carrier Doppler and code Doppler; matched-filter/FFT acquisition; the 20 ms GPS navigation-bit (data-epoch) boundary; and cellular-network GPS aiding messages. Both Qualcomm references presuppose exactly this skill set, and the '557 specification itself treats coherent integration as "well known in the art."

3. The claim elements to be met

Derived from the abstract and summary (element labels used below):

• E1 — receiver acquires a first segment and a second segment of a signal (signal of interest + noise/pseudo-noise) during different time periods;
• E2 — hypothesis generator produces hypotheses (code, code phase, Doppler);
• E3 — correlator derives first correlation data for segment 1 vs. hypothesis;
• E4 — correlator imposes a carrier phase offset on segment 2 so its carrier phase corresponds to that of segment 1;
• E5 — correlator derives second correlation data for the phase-shifted segment 2;
• E6 — combiner coherently combines first and second correlation data (real with real, imaginary with imaginary) → cumulative correlation data;
• E7 (method) — impose a code Doppler phase offset so code phases align despite unknown absolute code phases; segments of non-uniform length; iterate until an SNR threshold is met.

4. Primary combination: WO 00/14568 + WO 00/14560 (+ US 6,044,105)

4a. What each reference discloses

WO 00/14568 (Qualcomm) — primary. A DSP-based GPS receiver that stores a snapshot of chip×2 (or chip×8) I/Q samples and does a coarse search followed by fine searches, where "each fine search [is] performed on a different time segment of said fine search data" (claim 1). Disclosure specifics:

• "perform[s] rotation to eliminate frequency Doppler, and correlates over the search window … performs coherent integration and non-coherent combining and slews an IQ sample decimator as necessary to compensate for code Doppler."
• On the navigation-bit boundary: if E_n1 is the coherent sum before the boundary and E_n2 after, the unit "selects the maximum (in magnitude) of (E_n1 + E_n2) … and (E_n1 − E_n2) … to account for the phase change," with the option of non-coherent combination or avoiding the window.
• "multiple data windows are taken"; "to perform longer integrations only satellites with similar Doppler are searched over the same data"; system time is maintained by counting hardware 1 ms interrupts from the local oscillator.
• Claim 10 recites that "said different time segments overlap" — i.e., the reference expressly contemplates segments distinguished in time.

WO 00/14560 (Qualcomm) — motivation + alignment. Expressly frames the problem as one of sensitivity: "there is always some unknown frequency offset of the local oscillator … It is this unknown frequency offset that prevents longer coherent despreading and integration … Longer coherent would improve processing if the effects of the unknown frequency offset could be reduced." It teaches (i) deriving GPS time from a non-GPS source (a CDMA base station) before acquisition so that the local replica can be aligned and the correlator output "integrated over several code periods"; (ii) determining bit boundaries from the network so coherence can extend across 20 ms boundaries, and even across bit periods using known bit patterns; (iii) correcting frequency offset "either by controlling the frequency of the locally generated signal, or by periodic corrections within the correlator." Its US counterpart, US 6,208,292, adds that reverse-link frames are transmitted while GPS sampling proceeds, i.e., that sampling windows are dictated by when the RF/phone is available (https://www.freepatentsonline.com/[6208292](/patent/6208292).html).

US 6,044,105 (Gronemeyer) — the mechanism, and it is in this record. The '557 specification itself incorporates Ser. No. 09/145,055 → US 6,044,105 for "additional detail about this procedure and the matched filter 410." That reference teaches Doppler-correcting samples as they are stored, with residual Doppler removed by building a few Doppler offsets into the matched-filter tap logic. It is the admitted, incorporated mechanism for the very carrier-phase correction the claims recite. The ISA also cited it as a Y reference against this application.

Krasner references (US 5,945,944; 5,874,914; 5,841,396; etc.). Applicant-admitted background. US 5,945,944 (determining time for GPS receivers) teaches extracting timing signals from a communication system — "synchronized events marked by timing indicators, or … system time information" — and using them to establish GPS timing. US 5,874,914 teaches transmitting the Doppler frequency shifts of in-view satellites to the receiver from a base station, plus local-oscillator calibration and snapshot storage. These supply the external-timing/aiding inputs from which a phase offset between two captures is computed.

4b. Element-by-element mapping (primary combination)

Every claim element is disclosed by, or is an obvious design choice in view of, this combination.

4c. Motivation to combine (KSR / MPEP 2143)

1. The prior art states the motivation expressly. WO 00/14560 identifies the specific problem the '557 claims to solve — an unknown frequency offset preventing longer coherent integration — and proposes the specific solution (aiding-derived timing + in-correlator phase/frequency correction). Where "the prior art itself contains an express suggestion to do what the claim does," the motivation prong of § 103 is satisfied. In re Fulton; MPEP 2143(A).
2. Known technique to improve a similar device (KSR rationale C/D). Coherent integration was the textbook lever for SNR in spread-spectrum receivers, and both Qualcomm references apply it to the same class of device (a GPS receiver embedded in a cellular handset). Applying it to make the '557 receiver more sensitive is the predictable use of a known technique on a known device.
3. Finite number of predictable solutions. To raise acquisition sensitivity at fixed total dwell, the art recognizes only two levers: lengthen coherent integration (which requires phase alignment) or lengthen non-coherent integration (which incurs squaring loss — a trade-off expressly discussed throughout the field, and the very trade-off the '557 exploits). Choosing the coherent route, with phase alignment, is one of a small, identified, predictable set of options. MPEP 2144.04.
4. "Obvious to try" with a reasonable expectation of success. Qualcomm '14560 gives a reasonable expectation that network-derived GPS time plus bit-boundary knowledge makes multi-segment coherent integration work — and even quantifies the frequency-uncertainty/coherence-length trade-off in a table.
5. Market/regulatory pressure (design incentive). The FCC wireless E911 mandate (1996, with 1999/2001 implementation deadlines) drove GPS-into-handset integration, and the handset context supplies the reason the segments are disjoint and non-uniform: sampling is confined to slots in which the phone is not transmitting, per the '557 background itself. That reason is squarely present in US 6,208,292 (sampling when the RF is available).
6. No teaching away. Arguably the art counsels caution on long coherent integration (data-bit reversals, frequency drift). But the same references teach the solutions (network timing, bit-boundary information, frequency-hypothesis search, in-correlator correction). Disclosing a difficulty and its solution is not a teaching away from the solution.

5. Secondary combination: Krasner snapshot family + Qualcomm '14560 + Gronemeyer '105

An alternative framing uses US 5,781,156 / US 5,874,914 / US 5,884,214 / US 5,945,944 as the primary "receive and store a predetermined record length of a GPS signal, then process the stored samples" teaching. Those references supply E1–E3 outright (record-length captures processed by convolution/correlation, with base-station-supplied Doppler aiding and external timing). Adding Qualcomm '14560 supplies E4/E6/E7 (phase-aligned coherent integration across code periods, enabled by external timing) and US 6,044,105 supplies the Doppler-correction mechanics. The motivation is identical: to recover sensitivity when a single short snapshot is insufficient.

Optional third combination — the applicant's own earlier work. US 6,304,216 ("Signal detector employing correlation analysis of non-uniform and disjoint sample segments," filed 1999-03-30; https://patentimages.storage.googleapis.com/fb/0a/39/4a67f3eb6e70f5/US6304216.pdf) and US 6,577,271 ("Signal detector employing coherent integration," filed 1999-03-30; https://patentimages.storage.googleapis.com/cc/da/99/0081b48f0137c0/US6577271.pdf) together disclose (a) combining correlation analyses of multiple segments from separate and distinct time periods and (b) coherent integration of complex correlation products. Adding the carrier/code phase alignment yields the '557.

Important legal caveat on this third combination. US 6,304,216 and US 6,577,271 name the same sole inventor (Gronemeyer) as the '557. Under pre-AIA § 102(e), a reference must be "by another," and under § 102(a) the disclosure must be "by others." Their publication dates (2001, 2003) also postdate the '557 filing date (2000-04-18). They are therefore not § 102 prior art, and I do not rely on them as such. Their proper role is (i) evidence of the state of the art then known to the artisan, and (ii) obviousness-type double patenting — the '271 patent carries a terminal disclaimer ("subject to any disclaimer … a terminal disclaimer"), which is the classic fingerprint of an ODP objection within this family. The practical point stands: the '557 is a narrow increment over the same inventor's earlier, contemporaneous work.

6. Anticipation overlay (§ 102) worth noting

If the issued claims are close to the PCT claims, the ISA's X designation for WO 00/14568 alone suggests some claims may be anticipated, or at minimum rendered obvious by that reference standing alone (rotation to correct carrier Doppler + decimator slew for code Doppler + coherent integration across multiple time segments + phase handling at boundaries). Where a single reference with these features also teaches overlapping segments (its claim 10), non-overlapping/disjoint segments is at most an obvious variation — and is expressly motivated by the handset idle-slot constraint. I cannot confirm the claim-by-claim § 102 result without the verbatim claims.

7. Anticipated secondary-consideration rebuttals

• Commercial success: any success of the SiRF/CSR products (and the SiRF Technology v. Global Locate campaign described in the litigation section) lacks nexus — those products embody dozens of features, the '557 expired 2020-04-18, and no evidence ties sales to the claimed phase-offset combination.
• Unexpected results: none apparent. The benefit of coherent over non-coherent accumulation (faster SNR build, avoidance of squaring loss) is described in the '557 itself as known ("As is well known in the art, coherent integration enables faster and more efficient correlation than noncoherent correlation").
• Long-felt need / failure of others: the "need" was the FCC-driven weak-signal/indoor GPS problem, and the two Qualcomm references published one month before the '557 filing date already addressed it — belying any suggestion that the industry had failed.

8. Where the patent has the best chance of surviving (and why I'd still bet against it)

The strongest non-obvious hook is the specific computation in FIGS. 9 and 10A–10C: deriving a code-phase offset between two disjoint captures (and the iterative, threshold-driven accumulation) — the specification notes that ΔCP "is determined from the foregoing equations even though the underlying code phases CP1 and CP2 are unknown." A claim narrowed to that computation, as distinguished from a generic "phase offset," is the least likely to be met squarely by the cited art.

But that hook is weak on this record because (a) WO 00/14568 already teaches computing and applying a code-Doppler correction ("computes how long it takes to slip 1/16 of a chip and slews the decimator"); (b) WO 00/14560 teaches correcting frequency offset "within the correlator"; and (c) the residual algebra — getting ΔCP from a measured ΔT and the hypothesized Doppler — is routine in view of the Krasner timing references (US 5,945,944) that teach deriving GPS timing from cellular events. Combining a code-phase correction to a carrier-phase correction, where each alone was known and their joint use yields no more than the expected aggregate benefit, is a textbook § 103 case.

9. Bottom line

Conclusion: On the record of this application's own PCT search report, US 6,850,557 B1 would be prima facie obvious under § 103 over WO 00/14568 in view of WO 00/14560, further in view of US 6,044,105 and the Krasner timing/aiding references. The only elements not squarely quoted in the art I retrieved are the specific algebraic derivation of the inter-capture code-phase offset and the iterative, SNR-threshold-terminated accumulation, both of which are routine in view of the Krasner timing patents and Qualcomm's disclosed code-Doppler slewing — though I flag that I could not verify the verbatim claims, so the element-by-element mapping should be re-run against the official claim text.