Invalidity dossier

US 6704651

Method and apparatus for locating mobile receivers using a wide area reference network for propagating ephemeris

Current assignee: SiRF Technology, Inc.

Added 9/29/2026, 4:41:47 AM

At a glanceNo PTAB challenges2 lawsuits on fileasserted by SiRF Technology, Inc.Wireless Technologies

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Patent summary

Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.

✓ Generated

I'll search for authoritative information on this patent number, including any 2026 CAFC docket activity.

Let me search specifically for CAFC 2026 docket activity and litigation history.

Let me do one final check for any 2026 activity and for the terminal disclaimer/expiry status.

US Patent 6,704,651 — Analyst Summary

Sourcing note: I ran targeted searches against Google Patents (authoritative full text provided), the Federal Circuit's published opinion (cafc.uscourts.gov/opinions-orders/09-1262.pdf), and litigation aggregators (Unified Patents, Justia, ITC Pub. 4137). I found no 2026 CAFC docket activity for this patent — see the litigation/uncertainty section below.


Bibliographic Data

Field Value
Patent number US 6,704,651 B2
Title Method and apparatus for locating mobile receivers using a wide area reference network for propagating ephemeris
Application no. 09/989,558
Filing date November 20, 2001
Priority date July 13, 2000
Issue date March 9, 2004
Inventor Frank van Diggelen
Original assignee Global Locate, Inc.
Current assignee Avago Technologies International Sales Pte. Ltd. (via Broadcom → Avago chain of assignments 2015–2018)
Pre-grant publication US 2002/0032526 A1 (March 14, 2002)
Status Expired – Lifetime (adjusted expiration July 31, 2020)
Claims 3 total (1 independent)
Classification G01S 19/06, G01S 19/25, G01S 19/28, G01S 19/258

Family relationship: This patent is a divisional of application 09/615,105 (filed July 13, 2000), which issued as US 6,411,892. It is a member of a large family (Family ID 24463997) that includes US 6,587,789, US 6,703,972, US 6,813,560, US 9,599,720, and US 8,930,137, with counterparts EP 1305735 A4, JP 2004504612A, CN 100587514C, and WO 2002006987A1.


Abstract (as granted)

"A method and apparatus for distribution and delivery of global positioning system (GPS) satellite telemetry data using a communication link between a central site and a mobile GPS receiver. The central site is coupled to a network of reference satellite receivers that send telemetry data from all satellites to the central site. The mobile GPS receiver uses the delivered telemetry data to aid its acquisition of the GPS satellite signal. The availability of the satellite telemetry data enhances the mobile receiver's signal reception sensitivity."


Plain-Language Overview of the Independent Claim

The patent has only one independent claim — claim 1. There is no independent apparatus claim in the granted claim set (notwithstanding the "method and apparatus" title).

Claim 1 — A method of receiving GPS satellite signals, comprising three steps:

  1. Receiving satellite ephemeris at a first location. A reference station (or network of them) collects the precise orbital/clock data (ephemeris) broadcast by the GPS satellites. The patent explains that a single receiver cannot collect ephemeris for all satellites because each satellite only transmits its own; hence a geographically distributed network is needed.

  2. "Communication the satellite ephemeris" to a mobile GPS receiver at a second location. Literal-text caution: the granted claim reads "communication the satellite ephemeris" — this appears to be a typographical error in the printed claim ("communicating" was evidently intended). Per your instruction not to auto-correct identifiers/text, I flag it as-is. This step covers sending the collected ephemeris over a communications link (wireless, landline, internet, etc.) to the mobile device.

  3. Processing satellite signals at the mobile receiver using the ephemeris to reduce code and frequency uncertainty, thereby improving acquisition sensitivity. This is the heart of the invention: because the mobile receiver already knows where the satellites are (from the ephemeris), it can shrink the search window for code delay (pseudo-range) and Doppler/frequency, allowing longer integration times and detection of much weaker signals — e.g., indoors.

Dependent Claims

  • Claim 2 (depends on claim 1): the communicating step is performed through a wireless path.
  • Claim 3 (depends on claim 1): further comprising generating a pseudo-range model from the satellite ephemeris and communicating that model (rather than the raw ephemeris) to the mobile receiver. The specification notes the pseudo-range model is more concise, so the receiver performs fewer calculations; the preferred model comprises time T plus, per satellite: PRN number, pseudo-range, pseudo-range rate, and pseudo-range acceleration.

Supporting disclosure worth noting: the specification's "Sensitivity Enhancement" section (FIG. 8) describes solving the two-unknown clock equation y = c·dt_c − rangeRate·dt_s using the two strongest satellites to refine pseudo-range estimates for weaker ones — a concept central to related family patents (e.g., the '801 patent discussed in ITC Pub. 4137).


Litigation Posture

  • ITC Investigation 337-TA-602 ("Certain GPS Devices and Products Containing Same"), instituted April 30, 2007 at Global Locate's request. Respondent SiRF Technology et al. The ALJ found infringement of claims 1 and 2 of the '651 patent and no invalidity.
  • CAFC Appeal No. 2009-1262 — SiRF Technology, Inc. v. ITC, decided April 12, 2010. The Federal Circuit affirmed the Commission's finding that SiRF infringed the '651 and '000 patents, and affirmed the exclusion/cease-and-desist orders. It also upheld patent-eligibility of the method claims under the Bilski machine-or-transformation test (the method is tied to a particular machine — the GPS receiver). Broadcom Corp. (having acquired Global Locate in July 2007) was added as complainant in February 2008.
  • District Court: California Central District case 8:06-cv-01216 (per Unified Patents docket data).

Uncertainty / Caveats

  1. 2026 CAFC dockets: My searches returned no 2026 Federal Circuit docket, opinion, or order referencing US 6,704,651. Given the patent's legal status (expired July 31, 2020) and its last known appellate activity (2010), a 2026 CAFC appeal directly involving this patent would be unusual. I cannot affirmatively rule out a peripheral citation, but I found none. I recommend confirming directly via the CAFC CM/ECF docket search and USPTO Patent Center if a 2026 filing is specifically suspected.
  2. Assignee data is taken from the patent record's reassignment chain (Google Patents / EPO DOCDB); the record itself carries Google's standard disclaimer that assignee listings are not a legal conclusion.
  3. "Communication" in claim 1 is reproduced exactly as printed; whether it is a correctable clerical error would be a matter for the record/reexamination, not something I can resolve here.
  4. I did not retrieve the actual USPTO Patent Center or PACER filings directly (no direct database access); facts above are grounded in the patent full text, the Federal Circuit opinion PDF, and aggregator records cited in the search results.

Generated 9/29/2026, 4:50:59 AM

Cases on file (2)

Group view →

Specific litigation cases in our database that name US patent 6704651. The free-form analysis below may also discuss cases beyond this list.

Litigation summary

Past and pending lawsuits — plaintiffs, defendants, jurisdictions, outcomes, and notable rulings.

✓ Generated

I'll research litigation involving US patent 6704651 using the litigation databases. Let me start with the specific patent number and the leads already embedded in the patent record.

I found the core litigation. Let me dig into the specific case numbers and outcomes.

Let me pin down the companion ITC investigation (337-TA-596) and the district court case numbers.

Litigation involving US Patent No. 6,704,651

Bottom line: I found three proceedings that specifically name US 6,704,651 (the "’651 patent") — one ITC Section 337 investigation, the resulting Federal Circuit appeal, and a parallel district court action (in which the ’651 patent was asserted via counterclaim). All three arise from the Global Locate, Inc. / Broadcom Corp. v. SiRF Technology, Inc. dispute. The patent is listed as "Expired – Lifetime" (adjusted expiration 2020‑07‑31), and current assignee of record is Avago Technologies International Sales Pte. Ltd. (Broadcom family).

Note on scope: the ’651 patent was one of six Global Locate A‑GPS patents asserted together. I have not auto-corrected any numbers; I flag below where a related case asserted different patents.


1. ITC Investigation No. 337‑TA‑602 — "Certain GPS Devices and Products Containing Same"

Field Detail
Plaintiff/Complainant Global Locate, Inc. (San Jose, CA); Broadcom Corp. added as complainant Feb. 5, 2008 after acquiring Global Locate (July 2007)
Respondents/Defendants SiRF Technology, Inc. (San Jose, CA); E‑TEN Information Systems Co., Ltd. (Taiwan); Pharos Science & Applications, Inc. (Torrance, CA); MiTAC International Corp. (Taiwan); Mio Technology Ltd., USA
Jurisdiction U.S. International Trade Commission, Washington, D.C.
Case No. Investigation No. 337‑TA‑602
Filed/Instituted Complaint filed by Global Locate April 2007; investigation instituted May 7, 2007 (72 Fed. Reg. 25777)
Patents-in-suit ’801 (6,417,801), ’346 (6,606,346), ’000 (6,651,000), ’651 (6,704,651), ’187 (6,937,187), ’080 (7,158,080)
Outcome Violation of Section 337 found. ALJ Carl C. Charneski final ID Aug. 8, 2008 (evidentiary hearing Apr. 28–May 13, 2008); Commission final determination Jan. 15, 2009, modified in part and affirmed the violation; issued a limited exclusion order (as to the ’651 patent: claims 1 and 2) plus cease‑and‑desist orders against SiRF, Mio, and Pharos. Presidential review period expired March 16, 2009, with no disapproval.

The Commission specifically reviewed (and modified) the ALJ's finding that SiRF directly infringes claim 1 of the ’651 patent through its commercial activities — a key point on appeal.
Source: ITC Pub. 4137 / 74 Fed. Reg. notice — https://www.usitc.gov/intellectual_property/documents/pub4137.pdf and https://www.govinfo.gov/content/pkg/FR-2009-01-23/pdf/E9-1428.pdf


2. Court of Appeals for the Federal Circuit — Appeal No. 2009‑1262

Field Detail
Appellants SiRF Technology, Inc. (joined by E‑TEN, Pharos, MiTAC, Mio)
Appellee / Intervenor U.S. International Trade Commission; Broadcom Corp. / Global Locate, Inc. as intervenors
Jurisdiction U.S. Court of Appeals for the Federal Circuit
Case No. 2009‑1262
Filed SiRF filed its notice/opening appeal after the Presidential review period expired (opening brief May 1, 2009)
Outcome Affirmed (April 12, 2010) — SiRF Tech., Inc. v. Int'l Trade Comm'n. The court upheld the ITC on (1) Global Locate's standing (assignment/ownership of the ’346 patent), (2) direct infringement by SiRF, and (3) patent‑eligible subject matter of the method claims (machine‑or‑transformation, the GPS receiver being the machine). The exclusion/cease‑and‑desist orders were affirmed.

Sources: http://cafc.uscourts.gov/opinions-orders/09-1262.pdf ; Harvard JOLT digest — http://jolt.law.harvard.edu/digest/sirf-tech-inc-v-itc


3. SiRF Technology, Inc. v. Global Locate, Inc., et al. — C.D. Cal.

Field Detail
Plaintiff / Counter‑Defendant SiRF Technology, Inc.
Defendants / Counter‑Claimants Global Locate, Inc. and SBCG, Inc. (Global Locate's U.S. distributor)
Jurisdiction [U.S. District Court for the Central District of California (Judge James V. Selna)](/courts/central-district-of-california-judge)
Case No. 8:06‑cv‑01216 (Google Patents lists this as the "California Central District Court" case associated with US 6,704,651)
Filed SiRF's complaint December 15, 2006; Global Locate answered and counterclaimed on January 8, 2007, asserting, among others, US 6,704,651 (plus 6,542,820; 6,560,534; 6,606,346)
Status/Outcome Stayed (Oct. 3, 2007, pending the ITC proceedings); the entire action was ultimately dismissed without prejudice with each side bearing its own costs (docket entry Jan. 18, 2011).

Sources: Unified Patents litigation docket — https://portal.unifiedpatents.com/litigation/California%20Central%20District%20Court/case/8:06-cv-01216 ; Global Locate counterclaim press release (Jan. 8, 2007).


Related proceedings found (do NOT appear to assert the ’651 patent)

For completeness, these are part of the same dispute but asserted SiRF's or Broadcom's other patents, not US 6,704,651:

  • ITC Investigation No. 337‑TA‑596 — "Certain GPS Chips, Associated Software and Systems, and Products Containing Same." SiRF Technology, Inc. v. Global Locate, Inc., instituted March 13, 2007 (72 Fed. Reg. 11378), asserting SiRF's patents 6,304,216; 7,043,363; 7,091,904; 7,132,980 — the ’651 patent is not among them.
  • Broadcom Corp. v. SiRF Technology, Inc., C.D. Cal., complaint filed May 14, 2008, asserting four patents assigned to Broadcom. Per SiRF's 10‑K disclosures, these were the four patents for which SiRF sought ex parte reexamination; the filings I reviewed do not identify US 6,704,651 among them, but I could not confirm the full four‑patent list with high confidence.

Caveats

  • My searches were confined to the sources available to me (Google Patents' litigation links, the ITC's published notices and Pub. 4137, the CAFC opinion PDF, and Unified Patents' litigation docket). I did not obtain a complete PACER docket, so the district court filing date for 8:06‑cv‑01216 and any later reassignment/enforcement activity by Broadcom's successors (Avago/Broadcom) may be incomplete.
  • I found no other litigation specifically asserting US 6,704,651 beyond the Global Locate/Broadcom v. SiRF matters above. Because the patent expired July 31, 2020, further assertion and post‑expiration suits would not be expected. If you need a definitive exhaustion check, pull the full PACER docket for 8:06‑cv‑01216 and confirm the ITC EDIS record for 337‑TA‑602 (https://edis.usitc.gov), as those are the authoritative sources.

Generated 9/29/2026, 4:51:10 AM

Proceedings on file (0)

All PTAB activity →

AIA trial proceedings (IPR / PGR / CBM) filed at the USPTO Patent Trial and Appeal Board against this patent. Sourced from the USPTO Open Data Portal and refreshed every six hours; each proceeding number deep-links to the PTAB E2E docket.

Current assignee: SiRF Technology, Inc.

No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.

PTAB challenges

AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.

✓ Generated

I'll verify the canonical "no PTAB proceedings" default against web sources before writing up.

Proceedings overview

Zero. There are no AIA trial proceedings on file for US 6,704,651 — no inter partes review, no post-grant review, and no covered business method review, per the USPTO Open Data Portal (ODP) structured block, which I independently corroborated against the Unified Patents patent page, Google Patents' proceeding data, and general docket searches (all returned nothing; the Unified Patents page for US-6704651-B2 lists only "Patent Art (29)" prior-art references, not a proceeding).

Bottom-line defensive posture: there is no IPR history to leverage and no IPR history to fear. This is not a "hardened by two IPR survivals" patent, and it is not a "claims canceled" paper tiger. It is best characterized as untested at the PTAB and expired, meaning: (i) no petitioner is estopped under § 315(e)(2), so every prior-art ground remains fully available to a defendant in district court; (ii) there is no FWD to cite for or against claim 1; and (iii) the entire validity fight over this patent historically happened in the ITC (Inv. No. 337-TA-602) and the Federal Circuit (SiRF Tech., Inc. v. ITC, No. 2009-1262, decided 2010-04-12), not in AIA trials — because the AIA trial regime did not exist until 2012-09-16, and the critical litigation predates it.

Note on structured-data conflicts: none. The ODP block's default ("no PTAB activity on file") is consistent with every web source I checked. Nothing to flag as a contradiction.


Per-proceeding detail

None to report. Because the count is zero, the requested per-proceeding subsections (### {PROCEEDING_NUMBER} — {Petitioner} v. {Patent Owner}) would require proceeding numbers that do not exist. Per your constraint ("Do not invent proceeding numbers"), I am not manufacturing placeholders. I looked specifically for the following and found none:

  • IPR petitions by SiRF, Qualcomm, Broadcom, or any defensive aggregator against the '651 patent — none found.
  • PGR petitions — legally impossible here: PGRs are available only for patents with an effective filing date on or after 2013-03-16, and the '651 patent's priority date is 2000-07-13.
  • CBM reviews — inapplicable: the claims recite GPS signal processing (a technological invention), not a financial-product/service method. No CBM was filed.
  • Unified Patents involvement — Unified maintains a patent page and prior-art listing for US-6704651-B2 but shows no AIA challenge emanating from it. There is no defensive-aggregator IPR in this patent's chain.
  • Ex parte reexamination (a non-AIA, CRU proceeding, outside the PTAB list) — not surfaced in searches either, though I did not have direct reexam database access; treat this as unconfirmed rather than affirmatively negative.

Strategic summary

Claim status. Claims 1, 2, and 3 of US 6,704,651 stand exactly as granted — none canceled, none amended, none adjudicated at the PTAB. There is therefore no claim-level outcome map to build a defense around. Claim 1 (independent) remains intact on paper, including its literal oddity — "communication the satellite ephemeris" (apparently a typo for "communicating"), which is preserved as printed in the granted text referenced in the prior section. Claims 2 (wireless communicating path) and 3 (generate and communicate a pseudo-range model) are likewise untouched. The only judicial gloss on these claims is the Federal Circuit's 2010 affirmance in SiRF, which upheld the ITC's findings of infringement of claims 1 and 2 and rejections of invalidity, plus the court's Bilski-era holding that the method is tied to a particular machine (the GPS receiver) and thus patent-eligible. That is a favorable sheet for the patent owner — but it is a 2010 decision under the old § 101 framework, from an ITC record, and it does not collaterally estop a defendant from later § 102/§ 103 invalidity defenses in district court.

Estoppel landscape. There is no § 315(e)(2) estoppel attaching to anyone, because estoppel requires a final written decision, and no IPR/PGR was ever instituted, let alone decided. Practically, this is the most defendant-friendly posture available: a current or prospective defendant may assert any prior-art ground (patents, printed publications, public use, on-sale, prior invention, § 101, § 112) in district court or the ITC without the statutory narrowing that a prior IPR would have imposed. Conversely, there is no petitioner-side estoppel working against the patent owner's litigation position either. The prior SiRF ITC/CAFC invalidity trial — including the machine-or-transformation ruling — carries no binding res judicata effect on non-parties and no PTAB estoppel.

Pattern signals. No serial-petitioner pattern exists because there is no petitioner at all. This is unsurprising given the timeline: the patent was asserted hard in 2007 in the ITC and upheld on appeal in 2010, then the AIA trial regime opened in 2012 and the patent expired (adjusted expiration) on 2020-07-31. Litigants challenged it in the venue available at the time (the ITC), and by the time IPRs became the weapon of choice, the commercial incentive to file had largely evaporated as the patent aged toward expiry. The absence of IPRs is a timing artifact, not a signal of quality or vulnerability. Do not read it as a validation that the claims are bulletproof.

Expiration caveat. Because the '651 patent is expired, an IPR filed today would be of marginal value — the Board can still institute on an expired patent, but the practical upside is limited to neutralizing back-damages exposure in a pending suit filed within the § 315(b) one-year window of service. For a defendant weighing cost, a district-court invalidity defense or (where applicable) an ex parte reexamination are the more sensible vehicles; there is no FWD here that a defendant can hand the court.


Recommended next steps

  1. If you are a defendant receiving a demand letter citing US 6,704,651: there is no PTAB FWD, no IPR, and no canceled claim to cite. You cannot say "claim 1 is dead." You can say: (a) the patent expired 2020-07-31, so only past-damages exposure exists for pre-expiration conduct; (b) there is no PTAB proceeding, which means you face no § 315(e)(2) estoppel and may run the full spectrum of invalidity defenses; and (c) the sole merits precedent against a challenger is SiRF Tech., Inc. v. ITC, No. 2009-1262 (Fed. Cir. 2010-04-12), an ITC appeal with no preclusive effect on your district-court invalidity case, and resting on a § 101 analysis that predates Alice. Confirm the opinion at CourtListener (search "SiRF Technology v. International Trade Commission, 2009-1262") or the Federal Circuit's opinion archive.

  2. Verify the negative independently before relying on it. Since no proceeding exists to link, check (i) USPTO Patent Center / PTAB E2E "Trial" tab for application 09/989,558 and patent 6,704,651, (ii) the USPTO ODP PTAB API by patent number, and (iii) Docket Alarm / Unified Patents for any recently filed petition the ODP has not yet ingested. The ODP ingest lag is real; I found nothing, but a fresh filing would be the one fact that changes this analysis.

  3. Watch for ex parte reexamination. If a reexamination was filed, it would not appear in the AIA trial list and would be handled by the Central Reexamination Unit — confirm via Patent Center's "Reexamination" tab. I could not confirm or exclude one from open-web sources.

  4. If you are the patent owner/assignee (Avago/Broadcom): the absence of PTAB activity is neutral-to-favorable historically, but given expiry there is nothing to defend at the Board; focus any remaining enforcement on pre-2020 conduct and on the family members (US 6,587,789; 6,703,972; 6,813,560; 9,599,720; 8,930,137) that may have later expiration dates and are outside the scope of this memo.

Confidence and limits: I have high confidence that no AIA trial proceeding existed as of the most recent ODP ingest, because the structured source and all independent web checks agree. I have lower confidence on ex parte reexaminations and on filings within the ODP lag window, which I did not have direct database access to verify. No proceeding numbers, panels, or dispositions are reported above because none exist in any source I could find; anything else would be fabrication.

Generated 9/29/2026, 4:51:23 AM

Ownership chain (7)

Asserters network →

Structured records extracted from the assignment-history narrative below. Each entity links to its full ownership-network profile.

  1. 2000-07-13 · Assignment

    Frank van DiggelenGlobal Locate, Inc.

    employment assignment

  2. 2015-09-16 · Assignment

    Global Locate, Inc.Broadcom Corporation

    internal reorg

  3. 2016-02-11 · Security Agreement

    Broadcom CorporationBank of America, N.A., as Collateral Agent

    securitization

  4. 2017-02-01 · Assignment

    Broadcom CorporationAvago Technologies General IP (Singapore) Pte. Ltd.

    internal reorg

  5. 2017-02-03 · Release

    Bank of America, N.A., as Collateral AgentBroadcom Corporation

    securitization

  6. 2018-10-04 · reel 047195/0026 · Merger

    Avago Technologies General IP (Singapore) Pte. Ltd.Avago Technologies International Sales Pte. Limited

    internal reorg

  7. 2018-11-05 · Correction

    Avago Technologies General IP (Singapore) Pte. Ltd.Avago Technologies International Sales Pte. Limited

    paperwork correction

Assignment history

Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.

✓ Generated

I'll research the assignment record for this patent, starting with USPTO Assignment Center data and the parties in the chain.

Let me pull the specific assignment records — the Broadcom security agreement, the Global Locate→Broadcom assignment, and the Avago merger recordings.

Assignment & Ownership Analysis — US 6,704,651 B2

Data-access caveat up front (read before relying on reel/frame numbers): assignmentcenter.uspto.gov is a JavaScript application; its per-patent record pages were not retrievable as text in this session. Everything below is grounded in (a) the Google Patents "Legal Events / reassignment" record reproduced in the authoritative full text supplied for this analysis, (b) PlainSite's mirror of USPTO assignment data, (c) UKIPO/EPO register entries for the parallel European family members (same Recordal events, same patent family), and (d) U.S. and German court filings quoting the chain. Only one reel/frame number is actually documented in the record I could retrieve — 047195/0026 (quoted verbatim in the Google Patents reassignment entry for 2018-11-05). Every other reel/frame is marked not retrieved rather than guessed.


Inventors

Inventor Employer at filing Notes
Frank van Diggelen (sole named inventor) Global Locate, Inc. (San Jose, CA) Named on the parent application 09/615,105 (filed 2000-07-13) and on this divisional 09/989,558 (filed 2001-11-20).
  • Pattern check — inventor attrition: Not present. Public bios place van Diggelen at Global Locate through its 2007 acquisition by Broadcom, and he remained with Broadcom as a GPS/positioning technologist afterward. There is no "all inventors left the assignee within 12 months" signal here. (I could not verify his exact 2000-era title from a primary source in this session — commonly reported as a founder/CTO-level role — so I am not asserting a title.)
  • The US 2002/0032526 A1 publication and the granted front page both list a single inventor, so there is no joint-inventor split-rights issue in this chain.

Original assignee

  • Entity on the issued patent: Global Locate, Inc. (GLOBAL LOCATE INC, per the patent record and PubChem's mirror of the grant data).
  • Line of business: fabless GPS silicon and assisted-GPS infrastructure — Global Locate developed A-GPS baseband chipsets and the wide-area reference-network/A-GPS server architecture that this patent describes. It was not a licensing shop at the time of issue.
  • Did it ship a product embodying the claims? Yes, structurally. The patent's own architecture (reference-station network feeding ephemeris/pseudo-range models to a mobile receiver) is the architecture Global Locate commercialized, and Global Locate had standing as a complainant asserting this patent against SiRF — an assertion posture only an operating supplier with in-market products can realistically sustain.
  • Address history (a useful tell in this chain): Global Locate's registered correspondence address in family records moves from 208 Harristown Road, Glen Rock, NJ → 3190 S. Bascom, Suite 260, San Jose, CA → 5300 California Avenue, Irvine, CA 92617 (Broadcom's HQ). The UKIPO register shows that last change was filed 2015-11-04, accompanied by a "the above Application under Section 32 filed on 04.11.2015 was entered in error" correction — i.e., Global Locate's records were being repointed to the parent's address as the portfolio was swept up to Broadcom.
  • Current status: Acquired. Broadcom Corporation acquired Global Locate (reported at ~$146M in cash, announced/completed July 2007 — the dollar figure is from memory and I could not confirm it against a primary source in this session; the July 2007 acquisition date itself is corroborated by contemporaneous press coverage of the ITC action). Global Locate became a Broadcom subsidiary; its U.S. patent title was later formally assigned to Broadcom Corporation (see timeline). The downstream Avago entities are now part of Broadcom Inc. (AVGO).

Assignment timeline

Ordering note: the Google Patents reassignment entries give event dates; UKIPO register entries for the parallel EP family give deed dates for the same corporate transactions. Where these diverge, I flag it.

1. 2000-07-13 (executed) / recorded date not retrieved — Reel/Frame not retrieved

  • Conveyance: Assignment (inventor → employer)
  • Assignor: Frank van Diggelen
  • Assignee: Global Locate, Inc.
  • Correspondent: not retrieved (pre-issuance inventor assignment for parent app 09/615,105)
  • Context: Ordinary employment assignment. This record is asserted by inference from the granted front page ("Assignee: Global Locate, Inc.") — the Google Patents legal-events list does not surface a pre-2004 assignment event, so I cannot confirm the reel/frame.

2. 2015-09-16 (executed per Google Patents) / recorded 2015-11-26 (UKIPO counterpart) — Reel/Frame not retrieved

  • Conveyance: Assignment of Assignors' Interest ("ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)")
  • Assignor: Global Locate, Inc.
  • Assignee: Broadcom Corporation
  • Correspondent: not retrieved — see Signal 3.
  • Context: Parent-subsidiary IP consolidation — the formal vesting of the Global Locate portfolio in Broadcom eight years after the 2007 acquisition.
  • ⚠️ Date discrepancy to flag: Google Patents dates this event 2015-09-16; the UKIPO register records, for the same family transaction, a "deed of assignment dated 16.10.2015" registered 2015-11-26 (on EP 1835300 / EP 1581820 / EP 1695108). These are likely different dates in the same September–November 2015 recordal sweep rather than a contradiction, but the two sources do not agree on a face date and I am not reconciling them.

3. 2016-02-11 (executed) / recorded 2016-02-11 — Reel/Frame not retrieved

  • Conveyance: Patent Security Agreement (grant of security interest — not a title transfer)
  • Assignor / Grantor: Broadcom Corporation
  • Assignee / Secured Party: Bank of America, N.A., as Collateral Agent
  • Correspondent: not retrieved; PlainSite's mirror of the corresponding USPTO recording (plainsite.org/patents/assignment.html?id=8942852, "Patent Assignment from Broadcom Corporation to Bank of America, NA") lists this patent by title alongside US 9,497,452 and other Broadcom assets, confirming the '651 is inside the pledged portfolio.
  • Context: Securitization / collateral — the lien package supporting the financing of the Avago–Broadcom combination (Avago/Broadcom Cayman L.P. 10-Q for the quarter ended 2016-05-01 describes the "2016 Credit Agreement" with a collateral agent and the February 1, 2016 closing of the Broadcom Transaction). No ownership change.

4. 2017-02-01 (executed) / recorded 2017-02-01 — Reel/Frame not retrieved

  • Conveyance: Assignment of Assignor's Interest
  • Assignor: Broadcom Corporation
  • Assignee: Avago Technologies General IP (Singapore) Pte. Ltd.
  • Correspondent: not retrieved.
  • Context: Internal reorganization / intra-group asset transfer within the post-merger Broadcom group. Corroboration: an EPO file-history exhibit states "Exhibit A to November 28, 2016 Patent Assignment from Broadcom Corp" naming Avago Technologies General IP (Singapore) Pte. Ltd. as proprietor, and the EPO register shows that transfer taking effect 2017-05-11. So the umbrella deed appears to be dated 2016-11-28, recorded in the U.S. on 2017-02-01 and in Europe in mid-2017.

5. 2017-02-03 (executed) / recorded 2017-02-03 — Reel/Frame not retrieved

  • Conveyance: Termination and Release of Security Interest in Patents
  • Assignor / Releasing party: Bank of America, N.A., as Collateral Agent
  • Assignee / Beneficiary: Broadcom Corporation
  • Correspondent: not retrieved.
  • Context: Release of the 2016 securitization lien — closes out entry 3. Again no ownership change.

6. 2018-10-04 (executed) / recorded 2018-10-04 — Reel 047195 / Frame 0026

  • Conveyance: Merger ("MERGER (SEE DOCUMENT FOR DETAILS)")
  • Assignor / Disappearing entity: Avago Technologies General IP (Singapore) Pte. Ltd.
  • Assignee / Surviving entity: Avago Technologies International Sales Pte. Limited
  • Correspondent: not retrieved.
  • Context: Intra-group statutory merger (Singapore universal succession). The '651's title passed by operation of law, not by negotiated sale. Corroborated externally: Realtek's Delaware complaint (D. Del., gov.uscourts.ded.87314, Doc. 18) alleges the reorganization created "Avago Sales" and that "Avago General IP" was dissolved; a German judgment in the same dispute records that the former proprietor "ceased to exist as a legal entity as a result of the merger" and that this was a "universal succession."

7. 2018-11-05 (executed) / recorded 2018-11-05 — Reel 047195 / Frame 0026 (referenced)

  • Conveyance: Corrective Assignment — correcting the effective date of the merger previously recorded on Reel 047195, Frame 0026
  • Assignor: Avago Technologies General IP (Singapore) Pte. Ltd.
  • Assignee: Avago Technologies International Sales Pte. Limited
  • Correspondent: not retrieved.
  • Context: Paperwork correction only — same parties, same transaction as entry 6; recorded one month later.

No records exist after 2018-11-05. The chain has been static since; the patent expired 2020-07-31 (adjusted expiration per the record).


Timeline diagram

timeline
    title Ownership of US 6704651
    2000 : Filed by Global Locate Inc
    2001 : Divisional application filed
    2004 : Patent issued
    2007 : Global Locate acquired by Broadcom
    2015 : Portfolio assigned to Broadcom Corporation
    2016 : Lien granted to Bank of America
    2017 : Lien released
         : Assigned to Avago General IP Singapore
    2018 : Merger into Avago International Sales
         : Corrective assignment recorded
    2020 : Patent expired

NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT.
The only post-issuance transfers are to Broadcom Corporation (2015-09-16 event) and to Avago Technologies General IP (Singapore) Pte. Ltd. (2017-02-01), both subsidiaries/entities of a publicly traded operating semiconductor group (Broadcom Inc. / AVGO). The "IP" in "Avago Technologies General IP" is a nominal heuristic that points the wrong way here: the entity is documented in litigation as the group's patent-holding subsidiary and as a party substituting into real infringement suits (see Avago Technologies Fiber IP (Singapore) Pte. Ltd. v. IPtronics, N.D. Cal. 5:10-cv-02863, where patents were consolidated into Avago General IP and the prior holder "ceased to exist"). No registered-agent service address, no single-purpose Delaware/Texas LLC, no anonymous principal appears anywhere in the chain.

2. Known asserter in the chain — NOT PRESENT.
No assignee in this chain matches Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, or any Spangenberg-linked entity. The asserting parties in the ITC 337-TA-602 action were Global Locate, Inc. and later Broadcom Corporation — competitor-on-competitor, both shipping GPS silicon.

3. Repeat correspondent across the chain — UNCLEAR (data gap, not a finding either way).
I could not retrieve the correspondent of record for any of the six post-issuance recordings; assignmentcenter.uspto.gov did not yield record text in this session, and neither PlainSite's mirror (id=8942852) nor the Google Patents reassignment entries expose the correspondent field. The only related data point retrieved is that Broadcom-era recordings elsewhere in the portfolio name the receiving party as "Broadcom Corporation, 5300 California Ave., Irvine, CA 92617" and that the group's records were administered from that address — which is not the same thing as a named correspondent attorney, so I am not characterizing it as one. This signal cannot be scored without a direct Assignment Center pull.

4. Cascading transfers — NOT PRESENT (as an NPE signal).
There are three recorded events inside a 21-month window (2017-02-01, 2018-10-04, 2018-11-05), which superficially fits the pattern. It fails on the substance: all three are steps of one corporate group (Broadcom Inc. / Avago), the 2018-10-04 and 2018-11-05 entries are the same merger (the second is expressly a correction to "the effective date of merger previously recorded on reel 047195 frame 0026"), and no two assignees share a registered-agent address or a common third-party principal. The 2015 → 2018 sequence is the standard post-merger clean-up of an acquired subsidiary's portfolio, not a chain of purpose-built shells.

5. Pre-litigation transfer — NOT PRESENT (and the fact pattern is inverted).
The first infringement action naming this patent (ITC Inv. No. 337-TA-602, instituted 2007-04-30; parallel D. Cal. case 8:06-cv-01216) was filed by the then-owner, Global Locate. The recorded assignment to Broadcom came eight years later (2015). The one genuinely interesting timing fact is the reverse of the pattern the rubric asks about: Broadcom's July 2007 acquisition of Global Locate closed ~3 months after the ITC complaint was filed, and Broadcom was substituted/added as complainant in February 2008, which is the classic "acquire the plaintiff mid-case" posture for a competitor — not an NPE arranging standing to sue a stranger.

6. Bankruptcy fire-sale — NOT PRESENT.
No Chapter 7/11, no §363 sale, no assignment-for-the-benefit-of-creditors appears at any point. Global Locate was acquired as a going concern in 2007, and the 2015 recordation is a title clean-up, not a distressed disposition. (The 2016-02-11 Bank of America entry is a lien, not a liquidation — and it was released on 2017-02-03.)

7. Privateering — NOT PRESENT.
The two assertion episodes in this patent's life are direct competitor enforcement by the operating owner and its acquirer: (i) Global Locate/Broadcom v. SiRF (ITC 337-TA-602; CAFC 2009-1262, SiRF Tech. v. ITC, decided 2010-04-12, affirming infringement of the '651 and '000 patents), and (ii) the later Avago Technologies International Sales v. Realtek-customer actions in the UPC/German courts (2024). Neither involves an operating company funding a separate NPE to sue on its behalf.

8. Defensive aggregator — NOT PRESENT.
The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at Avago Technologies International Sales Pte. Ltd., the Broadcom group's operating/IP entity — which is itself an active litigant (see the 2024–25 German/UPC proceedings described in gov.uscourts.ded.87314). The patent's non-assertion today is explained by expiry on 2020-07-31, not neutralization.


Verdict

Operating-company assertion.

Justification: every recorded link in this chain is a corporate step of a publicly traded semiconductor manufacturer — Global Locate, Inc. → Broadcom Corporation (2015-09-16 event) → lien to Bank of America (2016-02-11) and its release (2017-02-03) → Avago Technologies General IP (Singapore) Pte. Ltd. (2017-02-01) → statutory merger into Avago Technologies International Sales Pte. Ltd. (2018-10-04, reel 047195/0026; corrected 2018-11-05). No licensing-only shell, no known NPE, no aggregator appears in the record, and the patent was asserted in-market by its owner against a direct competitor (ITC 337-TA-602 / CAFC 2009-1262). The single significant data gap is the correspondent of record, which I could not retrieve for any recording — that gap does not change the verdict, because the assignee identities themselves are all mainstream operating-company entities.

Verification links:

What I could not establish (do not treat as confirmed): the reel/frame identifiers for entries 1–5; the correspondent of record for any recording; the executed date of the inventor→Global Locate assignment; and the exact acquisition price for Global Locate. A direct Assignment Center pull on patent 6704651 would close all four gaps.

Generated 9/29/2026, 4:51:56 AM

Prior art

Earlier patents, publications, and products that may anticipate or render the claims unpatentable.

✓ Generated

I'll search for the prosecution-cited references ("Patent Citations") on US 6,704,651, since the authoritative full text you provided includes the "Cited By" lists but omits the front-page "References Cited."

Let me pull the definitive front-page "References Cited" list and the remaining entries of the prior-art set.

Prior-Art Analysis — US 6,704,651 B2

0. Scope, sourcing, and an important gap

Exact-number confirmation. Search results tie the requested number 6,704,651 to this record only: "US6704651B2 … Method and apparatus for locating mobile receivers using a wide area reference network for propagating ephemeris … Global Locate, Inc. … Frank van Diggelen" (Google Patents; PubChem US-6704651-B2; uspto.report/patent/grant/6704651). I did not return data for near numbers (e.g., 6,704,650, 6,704,652). Per your instruction I did not auto-correct anything.

Critical sourcing gap. The authoritative full text you supplied does not contain the front-page "References Cited" field. It jumps from classifications to the abstract/description and then to "Cited By (112)" and "Families Citing this family (131)" — those are forward citations, i.e., later documents citing the '651, not prior art. The backward (prior-art) citation list had to be reconstructed from two other sources:

  • Unified Patents patent page for US-6704651-B2, which lists "Patent Art (29)" — exactly 29 references, and
  • the '651 specification's own express citation of U.S. Pat. No. 6,064,336 (Krasner).

The 29-reference set below is therefore the operative citation list, but it should be verified against the printed front page / USPTO Patent Center. I could not open Patent Center or PAIR directly.

Flagged contradiction in the record (matters for § 102 math). The Google Patents text is internally inconsistent about the parent's priority date. The header says priority 2000‑07‑13, but the "Related Parent Applications" and "Applications Claiming Priority" tables list US 09/615,105 … 1999‑04‑23, and the family table repeats 1999‑04‑23 for US 6,411,892. This is not cosmetic — the effective § 102 cutoff shifts by ~15 months. I treat 2000‑07‑13 as the operative priority date (per the record header and the ITC's findings) but preserve the discrepancy as a live caveat.


1. The 29 cited references (backward prior art)

Dates in the "priority" column are as listed by the Unified Patents prior-art record. Grant/publication values are my best reading and are flagged for verification — I could not confirm every issue date directly, and dates marked unverified should not be relied on without checking the printed document.

# Reference Priority / filing (per record) Publication / grant (verify) Brief description
1 US 5,781,156 A — Krasner (SnapTrack) 1995‑10‑08 1998 "GPS receiver and method for processing GPS signals"; SPS signal acquisition/processing
2 US 5,831,574 A — Krasner 1996‑03‑07 1998 SPS receiver/processing
3 US 5,841,396 A — Krasner 1996‑03‑07 1998 "GPS receiver utilizing a communication link"
4 US 5,874,914 A — Krasner 1996‑12‑04 (family) 1999‑02‑23 "GPS receiver utilizing a communication link"
5 US 5,884,214 A — Krasner 1996‑09‑05 1999 SPS acquisition
6 WO 98/25157 A2 — Krasner 1996‑12‑03 1998‑06‑11 "An improved GPS receiver utilizing a communication link"
7 US 5,812,087 A — Krasner unverified 1998 SPS receiver (title not retrieved)
8 US 5,825,327 A — Krasner unverified 1998‑10‑20 GPS receivers and garments containing GPS receivers
9 US 5,945,944 A — Krasner unverified 1999 SPS timing/processing
10 US 5,999,124 A — SnapTrack 1998‑04‑21 1999‑12‑07 Satellite positioning augmentation with wireless communication signals
11 US 6,016,119 A — Krasner unverified 2000 SPS receiver/timing (title not retrieved)
12 US 6,052,081 A — Krasner 1997‑02‑02 2000‑04‑18 SPS-based time measurement
13 US 6,061,018 A — SnapTrack 1998‑05‑04 2000‑05‑09 Using altitude information in an SPS
14 US 6,064,336 A — Krasner (Qualcomm) 1998‑08‑05 2000‑05‑16 (stated in spec) "GPS receiver utilizing a communication link"; delivers almanac-derived Doppler aiding to a mobile
15 US 6,091,959 A — Motorola 1999‑06‑01 2000‑07‑18 Two-way wireless location-based message transmission
16 US 6,185,427 B1 — SnapTrack unverified 2001‑02‑06 "Distributed satellite position system processing and application network"
17 US 6,215,441 B1 — SnapTrack 1997‑04‑14 2001‑04‑10 "Satellite positioning reference system and method"
18 US 2002/0024461 A1 unverified 2002 Published "Satellite positioning reference system and method" application
19 US 6,324,473 B1 — Snaptrack/LeBlanc? 1997‑08‑03 2001‑11‑27 Collecting, processing and distributing differential GPS info using the Internet
20 US 6,473,030 B1 — Seiko Epson / Furuno 2001‑02‑27 2002‑10‑29 Infrastructure‑aiding for a satellite navigation receiver
21 US 5,899,957 A — Trimble 1994‑01‑02 1999‑05‑04 (verify) Carrier‑phase differential GPS corrections network
22 US 5,148,179 A — Allison 1991‑06‑26 1992 Differential position determination using satellites
23 US 4,751,512 A — Oceanonics 1986‑01‑20 1988 Differential navigation system for remote mobile users
24 US 4,884,208 A — Equipment Tracking Network 1988‑05‑15 1989 System for continuously establishing/indicating location of a movable object
25 US 5,187,805 A — Motorola 1989‑10‑01 1993 Telemetry, tracking and control for satellite cellular communication systems
26 WO 99/31524 A1 — Ericsson 1997‑12‑17 1999‑06‑24 Determining GPS receiver location using an estimated reference time
27 WO 99/19743 A1 — Ericsson 1997‑10‑14 1999‑04‑22 Reduced GPS receiver code‑shift search space for a cellular telephone system
28 WO 99/056144 A1 1998‑04‑27 1999 Providing location‑based information via a computer network
29 US 6,002,363 A — Krasner unverified 1999‑12‑14 Combined GPS positioning system and communications system utilizing shared circuitry

(The specification also expressly discusses #14, US 6,064,336, describing it as collecting "almanac data at a separate GPS receiver, then transmit[ting] the almanac data to a mobile receiver" so the mobile "can compute the expected Doppler frequency.")


2. § 102 analysis — reference-by-reference

Claim 1 (the only independent claim) requires ALL of:

  • (1a) receiving satellite ephemeris at a first location;
  • (1b) communicating the satellite ephemeris to a mobile GPS receiver at a second location;
  • (1c) processing satellite signals at the mobile receiver using the ephemeris to reduce code and frequency uncertainty, thereby improving acquisition sensitivity.

Claims 2 and 3

  • Claim 2: wireless path (adds nothing substantive beyond (1b)).
  • Claim 3: generating a pseudo-range model from the ephemeris and communicating that model.

Bottom line: For § 102, a reference must disclose every element in a single document. On the record as I found it, no single cited reference discloses the (1a)+(1b)+(1c) combination, and none discloses the claim‑3 pseudo-range‑model substitution. That is consistent with the empirical record: the ITC found claims 1 and 2 valid and infringed, and the CAFC (No. 2009‑1262) affirmed — i.e., the prior art of record did not invalidate claims 1–2.

Group A — Closest to claim 1 (reference-station network + ephemeris to mobile + sensitivity aid)

Reference Elements disclosed § 102 potential
US 6,215,441 B1 (SnapTrack, "Satellite positioning reference system and method") Reference/reference-station architecture; satellite data relayed to a mobile SPS receiver; aiding to shrink acquisition search Best single-reference candidate vs. claim 1 — if it transmits ephemeris (rather than almanac) and shrinks both code and frequency search. If it discloses only Doppler/frequency aiding, (1c) fails and the reference cannot anticipate. Claim 2 if the link is wireless. Does not reach claim 3.
US 2002/0024461 A1 Same subject matter, published form Only relevant if its pre‑2000 filing qualifies it under § 102(e); as a publication it post‑dates the priority.
US 6,185,427 B1 (SnapTrack, "Distributed satellite position system processing and application network") Distributed reference network (1a); distribution of data to remote units Architecture of (1a)/(1b); typically the server computes position, so (1c) at the mobile is absent → no anticipation.
US 6,324,473 B1 (DGPS over the Internet) Central collection + terrestrial distribution of satellite correction data (1a)/(1b) mechanics only; corrections ≠ ephemeris and are not used for acquisition-sensitivity → no anticipation of claim 1.
US 5,899,957 A (Trimble, carrier‑phase corrections network) Network of reference stations disseminating satellite corrections Same defect as above → no anticipation; background art only.

Group B — Closest to the result of claim 1(c) (search-window reduction), but not the ephemeris-from-a-network mechanism

Reference Elements disclosed § 102 potential
WO 99/19743 A1 (Ericsson) Cellular-assisted reduction of the GPS code‑shift search space Directly addresses reduction of code uncertainty (1c). If it also addresses frequency and uses network‑supplied ephemeris, it is a serious claim‑1 anticipation candidate. If it supplies only code-phase/Doppler aiding derived from the cell network without ephemeris, (1a)/(1c) fail.
WO 99/31524 A1 (Ericsson) Uses an estimated reference time to narrow search Addresses timing/search narrowing; no network-collected ephemeris to the mobile → no anticipation.
US 6,064,336 A (Krasner) Central/base collection of almanac; transmission to mobile; mobile derives Doppler Explicitly distinguished by the patent itself: the almanac "is only useful in reducing the frequency uncertainty and cannot be used to enhance receiver sensitivity by reducing the search window of code‑delay uncertainties." Because claim 1 requires reduction of both code and frequency uncertainty, this reference cannot anticipate claim 1; at most it meets a hypothetical frequency-only claim.
US 5,999,124 A, US 5,874,914 A, US 5,841,396 A, WO 98/25157 A2 (Krasner/SnapTrack family) SPS receiver using a communication link; aiding information (typically almanac/Doppler, sometimes satellite ephemeris) Each lacks a clear disclosure of the complete ephemeris to the mobile for dual code+frequency shrinkage → no anticipation of claim 1; § 103-class combination art.

Group C — Older network/differential-art (background only; no anticipation)

Reference Why it fails § 102
US 4,751,512 A (Oceanonics, 1988) Differential navigation for remote users; pre-dates SPS ephemeris-to-mobile acquisition aiding entirely.
US 4,884,208 A (1988) Object location network; no ephemeris, no acquisition-sensitivity teaching.
US 5,148,179 A (1992) Differential satellite position determination; corrections, not acquisition aiding.
US 5,187,805 A (Motorola, 1993) Satellite cellular TTC& telemetry; not a GPS acquisition-aiding system.
US 6,091,959 A, US 6,061,018 A, US 6,052,081 A, US 6,016,119 A, US 6,002,363 A, US 5,825,327 A, US 5,812,087 A, US 5,945,944 A, US 5,781,156 A, US 5,831,574 A, US 5,884,214 A, WO 99/056144 A1 Individual SPS-receiver/processing, timing, altitude, garment, or generic location-services disclosures; none discloses the wide-area reference network collecting ephemeris for all satellites and forwarding it to a mobile to shrink both code and frequency search windows.

Special case — US 6,473,030 B1 (item 20).
This is the one cited reference whose priority date (2001‑02‑27) post-dates the '651 priority (2000‑07‑13). If 2000‑07‑13 is correct, it is not § 102 prior art at all against '651 (it could only matter if the effective date were the 2001‑11‑20 actual filing — but '651 claims the earlier priority). This reference should be flagged for verification:

  • If the '651 priority is genuinely 1999‑04‑23 (the alternative date in the record), 6,473,030 is even further removed from qualifying.
  • If the '651 could only rely on its 2001‑11‑20 filing date, then 6,473,030 filed 2001‑02‑27 could be § 102(e) art — but its own grant (2002‑10‑29) is after '651's issue, so it would be § 102(e)-only, and its disclosure would still need to meet all of claim 1.

3. The three most relevant prior-art references

  1. US 6,064,336 (Krasner) — the reference the '651 specification itself rebuts. Its role is to define the almanac/Doppler boundary the invention claims to exceed. Potential § 102 target: alone, none of claims 1–3 (frequency-only aiding, almanac not ephemeris).
  2. US 6,215,441 B1 (SnapTrack) — the closest single-reference candidate against claim 1 (reference-station + mobile + aiding to shrink search); reaches claim 2 if wireless; not claim 3.
  3. WO 99/19743 A1 (Ericsson) — the closest art on the code-uncertainty-reduction element (1c); reaches at most part of claim 1.

Secondary but non-anticipatory: US 6,185,427, US 6,324,473, US 5,899,957 (system architecture / (1a)–(1b) only).

Empirical confirmation. The ITC found infringement of claims 1 and 2 of the '651 with no invalidity, and the CAFC affirmed (SiRF Tech., Inc. v. ITC, No. 2009‑1262, April 12, 2010), also upholding eligibility of the method claims under the machine-or-transformation analysis. Reporters summarizing the case note the ITC "認定 SIRF 公司侵犯 US6704651 的权利要求1~2" — i.e., claims 1–2 were held infringed and survived the prior-art challenge. This corroborates that the citations above, individually, do not anticipate claims 1–2.


4. Clarification on "patent citations" — do not confuse the two directions

Direction What it is Prior art?
"References Cited" (front page) — the 29 references in § 1 Documents the examiner/applicant cited against the '651 Yes — analyzed above
"Cited By (112)" and "Families Citing this family (131)" Later patents/applications that cite the '651 as prior art No — these are forward citations, useless for § 102 against the '651

If your intent was the forward "Cited By (112)" set, note that those documents post-date the '651 and therefore cannot anticipate it.


5. Caveats and open items

  1. The authoritative full text you provided does not include the '651's front-page "References Cited" field. The 29-item list is reconstructed from Unified Patents' "Patent Art (29)" record and the specification's express citation of US 6,064,336. Verify against USPTO Patent Center / the printed front page before relying on it as the complete official citation set.
  2. Issue/publication dates in the table are my best reading; those marked unverified or lacking a day/month should be confirmed against the printed documents. Priority dates are as listed by the aggregator.
  3. Titles not retrieved (US 5,812,087, US 6,016,119, US 5,945,944, US 5,884,214, US 5,841,396) are left as descriptors rather than guessed — I do not want to fabricate titles.
  4. Priority-date discrepancy (1999‑04‑23 vs 2000‑07‑13) in the Google Patents record is flagged; it directly affects whether US 6,473,030 and any 1999–2001 filings qualify as § 102 art.
  5. Anticipation is a per-claim, single-reference test. My element mapping above is a screening analysis based on the citations' titles/known subject matter and the specification's own characterizations; it is not a claim-by-claim verbatim reading of each reference's disclosure. A definitive § 102 opinion requires reading each reference against claim 1 element-by-element — which is exactly what the ITC did (and rejected).

Generated 9/29/2026, 4:52:16 AM

Obviousness

Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.

✓ Generated

I'll ground this obviousness analysis in the actual prior-art references associated with this patent. Let me pull the cited references and the key family/litigation context.

Let me pull the specific backward citations (References Cited) listed on the '651 patent and confirm the Taylor reference.

Let me verify the content of the key prior-art references in the '651 record so my mapping is accurate.

Obviousness Analysis — US 6,704,651 B2 under 35 U.S.C. § 103

Analyst note on scope. This builds on the two prior sections (bibliographic/claim summary and litigation posture) and does not repeat them. The prior-art set used here is the "Patent Art" / References Cited list carried on the patent record (the 29-item list on the Unified Patents page for US‑6704651‑B2, mirrored in the Google Patents "Cited By"/prior‑art fields), plus the reference the '651 specification itself discusses (Krasner, US 6,064,336), plus the ITC Investigative Staff's Notice of Prior Art in Inv. No. 337‑TA‑602 (Feb. 2008) referenced in the family record. I flag explicitly where I could not independently verify a reference's disclosure.


0. Two threshold flags before the merits

  1. Effective filing date is ambiguous in the record, but immaterial here. The Google Patents page gives "Prior art date 2000‑07‑13," yet the Related Parent Applications table lists the parent 09/615,105 with "Priority Date 1999‑04‑23." Earlier sections treated the priority date as July 13, 2000. Because every reference used in the lead grounds below has a pre‑1999 priority, the analysis is identical under either date. I flag it so the date discrepancy in the record is not silently resolved.
  2. Claim‑text caution (carried forward). Claim 1 recites "communication the satellite ephemeris" — reproduced as printed. All mappings below treat this step as communicating the ephemeris, consistent with the ITC/CAFC construction of claim 1 discussed in the litigation section.

1. Legal framework applied

  • Graham v. John Deere Co., 383 U.S. 1 (1966): scope and content of the prior art; differences between the prior art and the claims; level of ordinary skill; objective indicia.
  • KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007): a claim is obvious if the improvement is a predictable use of prior‑art elements according to their established functions, or if the combination was "obvious to try" over a finite number of identified, predictable solutions. Explicit teaching, suggestion, or motivation is not required.
  • Pre‑AIA § 102(e) applies to prior‑art US patents/publications by their earliest effective US filing date. The '651 patent is pre‑AIA (filed 2001‑11‑20).

2. Level of ordinary skill in the art (PHOSITA) as of mid‑2000

A person with a bachelor's degree in electrical engineering (or equivalent) and 2–5 years of experience in GPS/SPS receiver design or satellite navigation signal processing, conversant with:

  • the GPS Interface Control Document ICD‑GPS‑200 (satellite position/clock equations; the distinction between almanac and ephemeris, and that ephemeris is valid only ~2–4 hours);
  • assisted‑GPS architectures (basestation → mobile aiding data) typified by the Krasner "GPS receiver utilizing a communication link" family (US 5,841,396; US 6,064,336; US 5,874,914) and the Taylor reference (US 4,445,118);
  • the mapping of search dimensions in a GPS correlator: PRN code phase (code‑delay/pseudorange) and carrier Doppler (pseudorange rate) — the two quantities whose uncertainty the claim addresses.

This is a well‑developed, crowded art by 2000: A‑GPS aiding over cellular/paging networks was already an established commercial field.


3. Scope and content of the prior art

3.1 Primary references relied upon

Reference Date What it discloses (as relevant) Verification
US 6,064,336 (Krasner) — "GPS receiver utilizing a communication link"; and its §08/759,523 parent US 5,841,396; PCT WO 98/25157; EP 0 885 492 A1 filed 1996‑12‑04; '336 issued 2000‑05‑16 Basestation transmits satellite data information, expressly including "data representative of ephemeris" (EP 0 885 492 claims 34 and 39) to a mobile GPS unit over a two‑way pager/cellular link; the mobile derives Doppler from that data to cut acquisition time "by in excess of a factor of 10." Discloses "re-transmitting the satellite data messages to the remote... from the basestation" (Method 1). Also discusses Taylor '118 and the need to re‑transmit fresh aiding data because Doppler is short‑lived. Verified via EP 0 885 492 A1 and US 5,841,396 full text (search results); cited on the face of the '651 specification itself
US 6,215,441 (Snaptrack; Krasner, Sheynblat, Moeglein) — "Satellite positioning reference system and method" (CIP of 08/842,559, filed 1997‑04‑15) filed 1998‑04‑28 A plurality of SPS reference receivers dispersed over a geographic region, each transmitting into a communication network "satellite ephemeris data received from satellites in view"; digital processing systems coupled to the network receive that ephemeris and use it to compute position for mobile receivers. Explicitly frames the goal of a client/server A‑GPS architecture. Verified (abstract/claims via EP 1 075 665 B1 and US 6,215,441 claim text)
US 6,133,873 (Krasner) — "Method and apparatus for adaptively processing GPS signals" issued 2000‑10‑17 Searches over three parameters — satellite number, Doppler, and integration time — and optimizes each; a block‑processing method over hypothesized Doppler frequencies; "Receive Fix Command and Doppler Data From Base" — i.e., external Doppler aiding to shorten search and lengthen integration. Verified via the '873 patent PDF (search results)
Taylor et al., US 4,445,118 — navigation system with basestation → remote Doppler aiding 1984 Transmits Doppler/aiding from a control basestation to a remote GPS unit to speed acquisition; transmits a stable frequency reference to calibrate the remote oscillator. Verified via discussion in Krasner US 5,841,396 / US 2001/0028321
Ericsson WO 1999/019743 A1 — "Reduced global positioning system receiver code shift search space for a cellular telephone system" priority 1997‑10‑14 By its title and stated purpose, reduces the code‑shift (code‑phase) search space of a cellular‑hosted GPS receiver using network aiding — i.e., attacks code‑delay uncertainty, the second dimension the '651 claim recites. Title/record verified in the Patent Art list; full disclosure not independently read — treat as a title‑level characterization only

3.2 Secondary/corroborating references in the record

Reference Relevance Verification
US 6,185,427 — "Distributed satellite position system processing and application network" Network of distributed SPS processing with a reference/aiding layer. Listed in the record; content not independently verified
US 6,324,473 B1 — "Method and apparatus for collecting, processing and distributing differential GPS information using the Internet" (priority 1997‑08‑03; granted 2001‑11‑27) Collects reference‑station GPS data at a central facility and distributes it to remote users over a network — the "central site + wide‑area reference network + distribution" skeleton of claim 1. List/date verified; content characterized from title; independent read not performed
US 5,899,957 (Trimble) — "Carrier phase differential GPS corrections network" Wide‑area network of reference stations + central processing producing and distributing a derived correction product (rather than raw observables). Title/assignee verified; content not independently verified
RTCM SC‑104 differential correction standard (cited in Krasner '396's references) Establishes the practice of distributing a derived, compressed correction model to mobiles rather than raw satellite data — directly relevant to claim 3. Cited in the Krasner family record
US 5,999,124; US 5,781,156; US 5,831,574; US 5,884,214; US 5,945,944; US 5,812,087; US 6,051,018; US 4,751,512; US 5,148,179; US 4,884,208; WO 1999/031524 A1; US 6,091,959 Additional A‑GPS / differential / reference‑network art on the '651 record, generally cumulative to the primaries (aiding data over a link; networks of reference receivers; distributed processing). Listed in the record; not individually verified
US 6,473,030 B1 — "Infrastructure‑aiding for satellite navigation receiver" ⚠️ Likely NOT prior art. Its listed priority is 2001‑02‑27, after the '651 priority (2000‑07‑13). Excluded from the grounds below and flagged because it appears (unguarded) in the "Patent Art" list. Date from the record — appears to post‑date the '651 priority

4. Claim 1 — element‑by‑element mapping for the lead ground

Lead combination (Ground A): Krasner '336/‘396 family + Snaptrack '441, optionally in further view of Krasner '873 and Ericsson WO '743.

Claim 1 element Where disclosed Notes
Preamble: "A method of receiving global positioning system (GPS) satellite signals" Krasner '336; '441 Both concern receiving/processing GPS signals at a mobile unit.
(a) receiving satellite ephemeris at a first location Snaptrack '441: reference receivers "dispersed over a geographical region, each… transmitting, into a communication network, satellite ephemeris data received from satellites in view." This is a literal disclosure of collecting ephemeris at a first (reference) location — including the express premise that a network is needed because one receiver cannot see all satellites.
(b) communicating the satellite ephemeris to a mobile GPS receiver at a second location Krasner '336/‘396: basestation transmits satellite data information (and, expressly, "data representative of ephemeris" per EP 0 885 492 claims 34/39) over a pager/cellular link; Taylor '118: Doppler aiding over a control link; '441: the network feeds mobile receivers via cell‑based wireless. Disclosed for both almanac and ephemeris; the claim does not limit the link type (that is claim 2).
(c) processing satellite signals at the mobile receiver using the ephemeris to reduce code and frequency uncertainty to improve acquisition sensitivity Frequency dimension: Krasner '336 ("reducing its processing time by in excess of a factor of 10" via derived Doppler); Krasner '873 (Doppler + integration‑time optimization). Code dimension: Ericsson WO 1999/019743 (title: "Reduced GPS receiver code shift search space…"); the well‑known ICD/ephemeris relationship between satellite position and pseudorange. Combined sensitivity effect: Krasner '873's optimization of integration time vs. number of search bins. This is the only element requiring assembly. The '651 specification's own §"Signal Detection" concedes the mechanism (fewer bins ⇒ longer integration ⇒ greater sensitivity) is grounded in known receiver behaviour; the invention's contribution is completing the ephemeris set in advance so both windows can be narrowed.

Observation on Ground A: Element (a) is met literally and entirely by Snaptrack '441; elements (b) and the frequency half of (c) are met by Krasner '336; and the code‑phase half of (c) is supplied by WO '743 (and/or by the ordinary knowledge that ephemeris — unlike almanac — fixes satellite position precisely enough to bound pseudorange).


5. Motivation to combine (KSR factors)

The record supplies strong, record‑internal motivations:

  1. The "circularity" problem the patent itself names. The '651 specification states GPS receivers need a high‑strength signal to extract ephemeris, but need ephemeris to acquire weak signals — "an inherent circularity that makes it difficult or impossible for GPS receivers to acquire signals in low signal strength environments." Krasner '336 identifies the same problem. Where the prior art itself frames the problem, the motivation is inherent, not hindsight.
  2. Same field, same problem, same architecture. All primaries are A‑GPS/SPS references addressing acquisition time and receiver sensitivity via a communication link. KSR — combination of references addressing the same problem is presumed motivated.
  3. Ephemeris‑vs‑almanac is a known, finite design choice. Both the '651 specification and Krasner distinguish almanac (good only for frequency uncertainty) from ephemeris (good for both frequency and code‑delay uncertainty, because it carries precise position, velocity, and clock error). Krasner's own family already discloses transmitting ephemeris (EP 0 885 492 claims 34/39). Choosing ephemeris over almanac is a predictable substitution with a known benefit, exactly the KSR "finite number of identified, predictable solutions" scenario.
  4. The network premise is conceded. The '651 specification states the three‑station minimum and the four‑station practical network because "each satellite only transmits its own ephemeris" — precisely the reasoning Snaptrack '441 had already published (dispersed reference receivers, ephemeris aggregated over a communication network).
  5. Design incentives are documented. Krasner '336's Method 1 = "re‑transmitting the satellite data messages to the remote from the basestation"; '441's client/server A‑GPS; WO '743's explicit code‑shift reduction; Krasner '873's integration‑time optimization — each supplies a distinct, non‑overlapping piece, and the whole achieves the stated goal (indoor/low‑signal acquisition).
  6. Reasonable expectation of success. Deterministic geometry: from satellite ephemeris and an approximate position/time, the pseudorange and Doppler for a given satellite are computable to well within a code epoch and Doppler bin. Nothing in the combination is unpredictable; no biological/physical unpredictability attends it.

6. Dependent claims

Claim 2 — "said communicating step is performed through a wireless path"

Disclosed by Krasner '336/'396 (two‑way pager or cellular telephone link to the mobile unit), '441 (cell‑based wireless coupling of mobiles to the processing systems), and Taylor '118 (RF link). Obvious to any degree of confidence once claim 1's second step is met — wireless is the paradigm A‑GPS transport named repeatedly in the primary references themselves.

Claim 3 — "generating a pseudo‑range model from said satellite ephemeris and communicating the pseudo‑range model to the mobile receiver"

Supporting references:

  • Derived‑product distribution is old and conventional: RTCM SC‑104 differential corrections (cited in the Krasner family) transmit a derived, compact correction product to mobiles rather than raw data — the same architectural choice claim 3 recites.
  • '441 has digital processing systems compute position/derived quantities at the server from network‑received ephemeris, then serve mobiles.
  • WO '743 transmits reduced search‑space aiding (a model of the search space) to the handset.
  • The specification itself treats client/server split as a free choice: "The computation of the pseudo‑range model can be done at the mobile receiver, or at the central processing site." Distributing computation between server and client for bandwidth/battery/power savings is a predictable design choice under KSR.

Motivation for claim 3: (i) the model "is more concise than the complete ephemeris" (the '651 specification's own words), reducing over‑the‑air bandwidth and mobile computation/energy — routine design objectives in 2000 cellular data; (ii) legacy of differential‑correction distribution; (iii) centralizing computation promotes consistency across many mobile receivers. A POSITA would have been motivated to transmit the compact derived model instead of raw ephemeris for exactly these reasons.


7. Alternative grounds (as an examiner would plead them)

Ground Combination Claim(s) targeted Core logic
A Krasner '336/‘396 + Snaptrack '441 (+ Krasner '873 / WO '743) 1, 2 Network collects ephemeris ('441) + basestation transmits satellite data incl. ephemeris to mobile ('336) + Doppler and code‑shift search reduction ('873 / WO '743) ⇒ both uncertainty dimensions narrowed, sensitivity improved.
B US 6,324,473 (collect/process/distribute differential GPS info over the Internet) or Trimble '957 + Krasner '336 + Krasner '873 1, 2, 3 The reference‑network + central‑distribution architecture is old ('473/'957); combining it with the known basestation→mobile aiding of '336, and with derived‑product distribution (RTCM/'957), yields claim 3's pseudo‑range model as a predictable compacting step.
C Taylor '118 + Snaptrack '441 + Krasner '873 1, 2 Taylor establishes basestation→remote aiding (Doppler) as of 1984; the rest is the ordinary substitution of the more accurate ephemeris for almanac, plus code‑shift reduction.

8. Weaknesses and counter‑arguments the record must confront

An honest § 103 analysis must note the following, several of which cut against the above grounds:

  1. The almanac/ephemeris distinction is the crux, and the lead reference transmits almanac. Krasner '336's headline embodiment transmits almanac, which the '651 specification correctly says "cannot be used to enhance receiver sensitivity by reducing the search window of code‑delay uncertainties." The obviousness case therefore depends on (i) the express ephemeris‑transmission disclosures of the same family (EP 0 885 492 claims 34/39) and/or (ii) a separate code‑shift reference (WO '743). If the fact finder credits only the almanac embodiment of '336, the code‑delay half of element (c) is not met by that reference alone.
  2. I did not read the full text of WO 1999/019743, US 6,473,030, US 6,324,473, US 5,899,957, US 6,185,427, US 5,999,124, or US 6,091,959. My characterizations of these are title/abstract‑level. A rigorous invalidity contention requires full‑text review with pin cites. This is flagged, not glossed.
  3. US 6,473,030 appears to post‑date the '651 priority and should be excluded from any ground — an example of why the "Patent Art" list should not be adopted wholesale.
  4. The tribunals rejected invalidity on this art. Per the earlier litigation section, in Inv. No. 337‑TA‑602 the ITC found no invalidity of claims 1–2, and the Federal Circuit (No. 2009‑1262, Apr. 12, 2010) affirmed. Whatever the analytical merits of the grounds above, the actual adjudicators, applying Graham/KSR, did not find the claims obvious over the asserted art (including the Staff's Notice of Prior Art). This is a material data point against the strength of the grounds, though it is not dispositive of what a hypothetical claim‑by‑claim § 103 analysis should conclude on a different record.
  5. Objective indicia (secondary considerations) run toward the patentee. The record contains evidence of industry adoption of A‑GPS with pre‑positioned ephemeris (the SiRF "InstantFix" products found to infringe), broad licensing of the Global Locate family, and Broadcom's July 2007 acquisition of Global Locate (per the earlier sections). These are classic non‑obviousness‑weighty indicia (commercial success, licensing, industry acclaim) and would be weighed by a fact finder under Graham factor four — I take no position on their ultimate weight, and note they depend on a nexus between the indicator and the claimed subject matter, which I have not assessed.

9. Bottom line

  • Legally defensible § 103 grounds can be constructed — most cleanly Krasner '336/'396 + Snaptrack '441, with Krasner '873 and Ericsson WO '743 supplying the Doppler‑ and code‑shift‑reduction teachings, and the RTCM/'441/‘473 server‑side‑derivation art supporting claim 3. The motivation to combine is strong and largely internal to the references: the same field, the same stated circularity problem, the documented almanac‑vs‑ephemeris trade‑off, and Krasner's own express ephemeris‑transmission disclosure.
  • But the grounds are not airtight. Their linchpin — using ephemeris (not almanac) to reduce code‑delay uncertainty — is only fully supported once WO '743 (title‑level only, unread in full) or the express ephemeris claims of the Krasner family are added. Several secondary references are unverified.
  • The historical record contradicts these grounds: the ITC and the Federal Circuit resolved the actual invalidity challenge in the patentee's favour, and objective indicia (licensing, acquisition, commercial adoption) point toward non‑obviousness. I present the grounds as an analytical exercise, not as a prediction that the claims would have been held invalid.

Confidence: The element‑to‑reference mappings for Krasner '336/'396 and Snaptrack '441 (elements (a) and (b), and frequency‑half of (c)) are high confidence and verified. The code‑delay half of (c) and all of claim 3 are moderate confidence, contingent on full‑text review of the references flagged in § 8.2.

Generated 9/29/2026, 4:52:29 AM

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