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Work Assignment 2: Critical Product Mapping Report
Version: 6.9 Date: 22 September 2026 Prepared by: Ben Wortley, Lead Consultant — UN-GGCE Reference: Terms of Reference 2 (ToR2) — Work Assignment 2
Full version history and changelog available on request.
Audience
This report serves two readerships: (1) UN-GGCE leadership and technical counterparts already familiar with this engagement; and (2) UN-GGCE staff and Member State stakeholders new to this specific analysis. Readers new to the engagement should read this Purpose and Reading Guide; the sections that follow provide the full technical detail underlying its conclusions.
Purpose and Reading Guide
This report is one of five deliverables produced under Terms of Reference 2 (ToR2) of the UN-GGCE consultancy engagement, the Global Geodesy Supply Chain Assessment. Work Assignment 2 requires the mapping of the end-to-end delivery workflows for the five critical geodetic products, expressed using the Essential Geodetic Variables (EGV) framework, so that risks and investment priorities can be assessed in Work Assignments 3 through 5.
This assessment builds directly on the State of Geodesy 2026: A baseline maturity assessment (UN-GGCE, 16 March 2026)[^sog2026] — the capability maturity baseline produced during the consultancy phase before this one (Terms of Reference 1, "ToR1," March–September 2025), through consultation with more than 130 experts across the international geodetic community. This report takes the next step: attaching that baseline to the structure of the supply chain itself, function by function, so Work Assignment 3 can identify where risk concentrates and where investment will have the greatest effect.
In plain terms: the global geodesy supply chain is the international network of observatories, data centres, analysis centres, and combination centres that produces the reference frames, satellite orbits, Earth orientation parameters, and gravity models on which satellite navigation, Earth observation, surveying and mapping, and disaster response all depend. This report maps how each of five critical products is actually produced — function by function, institution by institution.
Companion Documents
For readers who are new to this engagement, four companion documents provide the necessary context:
- Work Assignment 1 — Guiding Principles — read this first; the six principles listed for reference in §1, against which Work Assignment 3 assesses this report's mapping.
- Work Assignment 1 Appendix — EGV Data Levels and Supply Chain Functions — defines the data-level classification and the function structure this report applies to each product. Read alongside Work Assignment 1 or immediately after.
- Work Assignment 2 Appendix — Business Architecture Taxonomy — defines the Workflow, Capabilities, Organisations, and Information Artifacts primitives this report's tables use, per the BIZBOK Value Stream primitive. Read alongside this report, before Sections 3–7.
- Work Assignment 2 Annexes (five Workflow Description documents) — the detailed, function-by-function basis for each product's summary in Sections 3–7 below.
This report is pure structural mapping — it doesn't compute or reference the risk-scoring method which will be included in future deliverables.
Key Terms
| Abbreviation | Full term |
|---|---|
| ACC | Analysis Centre Coordinator (IGS) — combines independent orbit solutions from multiple Analysis Centres into the single official product (Satellite Orbits F5); distinct from CDDIS, which only archives and distributes data |
| Bulletin A / Bulletin B | Earth Orientation Parameter products: Bulletin A is a rapid series published weekly by USNO for near-real-time use; Bulletin B is the final, definitive monthly series published by SYRTE (see Section 5) |
| CDDIS | Crustal Dynamics Data Information System (NASA GSFC, USA) — one of three Global Data Centres that archive and distribute raw and processed geodetic data (the archiving function in each product's workflow — function number varies by product); does not perform combination |
| DORIS | Doppler Orbitography and Radiopositioning Integrated by Satellite (a positioning technique) |
| EGV | Essential Geodetic Variable |
| EOP | Earth Orientation Parameters |
| GGOS | Global Geodetic Observing System — IAG's coordinating body for the geodetic techniques below |
| GNSS | Global Navigation Satellite Systems |
| IAG | International Association of Geodesy — the scientific body GGOS and the technique services below sit under |
| ICRF | International Celestial Reference Frame |
| IDS | International DORIS Service |
| IERS | International Earth Rotation and Reference Systems Service |
| IGN | Institut national de l'information géographique et forestière (France) |
| IGS | International GNSS Service |
| ILRS | International Laser Ranging Service |
| ITRF | International Terrestrial Reference Frame — the specific realization of the ITRS below |
| ITRS | International Terrestrial Reference System |
| IVS | International VLBI Service for Geodesy and Astrometry |
| PPTD | People, Process, Technology, Data (capability maturity dimensions) |
| SLA | Service Level Agreement |
| SLR | Satellite Laser Ranging |
| SPOCC | Satellite orbit combination software operated for the IGS (GFZ Potsdam) |
| VLBI | Very Long Baseline Interferometry |
1. Introduction
This report maps the end-to-end delivery workflow for five critical Essential Geodetic Variable (EGV) products — Satellite Orbits, the International Terrestrial Reference Frame (ITRF), Earth Orientation Parameters (EOP), the International Celestial Reference Frame (ICRF), and the Global Earth Gravity Field — using the Business Architecture primitives defined in the Work Assignment 2 Appendix: each product's Workflow — the BIZBOK Value Stream primitive, realised here as a sequence of production Functions — the Capabilities each function draws on, the Organisations that perform it, and the Information Artifacts it produces. Scope, per the Terms of Reference: a product mapping report with workflow diagrams showing capability dependencies for each of the five critical products. Quantitative risk scoring, investment sequencing and gap prioritisation are Work Assignment 3's job; this report's job is to make the structure itself — and where it objectively lacks a matching capability, or rests on a single organisation — visible and traceable.
This mapping is the structural basis Work Assignment 3 assesses against the six Guiding Principles established in Work Assignment 1 (Guiding Principles, v4.6) — listed here for reference:
- Principle 1: Geographic Distribution
- Principle 2: Political Resilience and Distributed Operational Control
- Principle 3: Centralised Accountability through Multilateral Governance
- Principle 4: Technical Interoperability and Data Accessibility
- Principle 5: Minimum Capability Maturity
- Principle 6: Transparency, Monitoring and Performance Assurance
This report maps structure only — a capability shortfall (no real capability from the State of Geodesy 2026 model matches what a function actually needs) or an organisational dependency (a function resting on a single institution or jurisdiction with no demonstrated alternative) is visible directly in the tables below wherever it exists, without being scored, ranked, or referenced against a specific Guiding Principle. Assessing what these structural facts mean against the six Principles, and prioritising the results, is Work Assignment 3's job in full — not summarised or previewed here.
Status of these findings: both the function structure and the capability mapping in this report are asserted — built from the real evidence collected during this engagement's own pre-work (primary-source research on each product's actual production workflow, the published State of Geodesy 2026 capability model, and cross-checks against Nick Brown's own worked example and methodology). Confirmation happens separately, through the Technical Product Working Groups' (TPWG) own formal bottom-up process (
ROBUSTNESS_TESTING_PROCEDURE_v1.6Section 6.3), which the TPWGs will run themselves, most likely starting from a blank canvas or a high-level framework. What this report's assertion is for: testing that the full end-to-end process — capability mapping through to maturity, risk, investment and sequencing — actually holds together as a coherent pipeline, using real evidence, ahead of the TPWGs' own formal elicitation. The Technical Product Working Groups (one per product, drawn from IGS, IVS, ILRS, IDS, and IERS) will independently confirm or challenge which functions actually exist in each product's real workflow and which capabilities apply to each; their input can change every function and every mapping below. Read this report as a working draft testing the pipeline end to end.
The five EGV pipelines assessed in this report span EGV Levels 2 and 3 in the GGOS EGV framework (V7.0, January 2026) and collectively constitute the core of the global geodesy supply chain. Their workflows are formally described in the following documents, each updated as part of WA2 with per-function capability, organisation and artifact detail:
- Satellite Orbits Workflow (Work Assignment 2 Annex, v7.0)
- ITRF Workflow (Work Assignment 2 Annex, v4.4)
- EOP Workflow (Work Assignment 2 Annex, v4.5)
- ICRF Workflow (Work Assignment 2 Annex, v4.4)
- Global Gravity Model Workflow (Work Assignment 2 Annex, v4.2)
2. Methodology
Approach. For each product, the workflow is broken into named functions (numbered F1...Fn, one per genuinely distinct production step — see Function derivation, below). For each function this report identifies: the real capabilities from the State of Geodesy 2026 58-capability model that apply (with People/Process/Technology/Data maturity shown as descriptive context); the organisation(s) that perform it; and the information artifact it produces, following the lifecycle defined in the Work Assignment 2 Appendix's Primitive 4 (raw observational data → standardized observation logs → uncombined solutions/normal equations → integrated multi-technique solution → published ephemerides and models). This is a mapping exercise only, per the Terms of Reference — assessing what the mapping means against the six Guiding Principles is Work Assignment 3's job.
Function derivation. Each product's workflow is decomposed into functions at the granularity needed to keep organisationally and technically distinct steps visible — typically seven to nine per product, checked against primary coordinating-service documentation.[^agy-validation] First-mile telemetry is kept distinct from archiving; VLBI correlation, where present, is kept distinct from per-technique analysis; validation is kept distinct from dissemination — collapsing any of these together would hide real maturity and organisational differences (for example, EOP's VLBI-technique analysis scores 2.25 against GNSS-technique analysis's 3.75, a gap invisible if both sat in one combined row). Where a capability's existing PPTD score was assessed at a coarser grouping than this report now uses, and a clean per-function split of the underlying evidence isn't yet available, the same score is shown at each of the finer functions it now spans, explicitly flagged as not yet separately assessed — this report does not invent new numbers to fill the gap. Where a function has no State of Geodesy 2026 capability scored against it at all, that is stated plainly as a coverage gap.
Capability maturity source. All People, Process, Technology, Data (PPTD) scores in this report are drawn from the State of Geodesy 2026[^sog2026] — fifty-eight capabilities assessed on a 1–5 scale during Terms of Reference 1 (March–September 2025) — supplemented where noted by IGS Technical Reports (2013, 2018) and IAG/GGOS primary sources. They are shown per function as descriptive context only; this report does not compute or report a derived risk score from them, and does not assess them against the six Guiding Principles — that analysis, and the resulting investment sequencing, belongs to Work Assignment 3 in full.
3. Satellite Orbits (EGV Level 2)
Workflow document: Satellite Orbits Workflow (Work Assignment 2 Annex, v7.0)
The Satellite Orbits supply chain produces the GNSS Satellite Orbits, Clocks and Biases (GOCB) product set — three-dimensional orbital trajectories and sub-nanosecond clock corrections for all operational GNSS satellites. As a Level 2 EGV, it is an upstream prerequisite for ten of fourteen Level 3 EGVs, including the ITRF, EOP, sea level, ice sheets, and terrestrial water storage. A critical circular dependency exists with the ITRF: each requires the other as a processing input, meaning failure in either pipeline degrades both.
The workflow comprises seven functions, F1 through F7, checked against how IGS itself documents the pipeline.[^agy-validation] The three Operational Data Centres (F2) concentrate in the Northern Hemisphere; orbit validation (F6) depends on an entirely separate technique, SLR, with its own organisational footprint. All decentralised resilience built across F1–F4 converges at a single organisational bottleneck — the Analysis Centre Coordinator (ACC) and the Software for Precise Orbit and Clock Combination (SPOCC) at F5.
Functions, Capabilities, Organisations and Information Artifacts
| Function | Capabilities (People / Process / Technology / Data) | Organisation(s) | Information Artifact |
|---|---|---|---|
| F1 — Global Multi-GNSS & DORIS Tracking | Ground-Based Asset Management (3/2/2/3); Equipment Calibration and Maintenance (4/3/3/0); GNSS Data Acquisition and Storage (4/4/3/3); DORIS Data Acquisition and Storage (4/4/4/4) | Multi-GNSS tracking stations under ~80 national mapping/research agencies, coordinated by the IGS Infrastructure Committee; DORIS beacon network (CNES, France) | Raw Observational Data (raw GNSS/DORIS binary) |
| F2 — First-Mile Telemetry & Station Ingestion | Network Operations (2/2/1/3) | Operational Data Centres: GFZ (Germany), CNES REGINA (France), NGS/NOAA (USA) — all three Northern Hemisphere[^agy-validation] | Transported GNSS/DORIS Observation Streams |
| F3 — Regional & Global Archiving & Equalization | Data Quality Management (2/2/1/3); Metadata Management (2/2/1/3); Data Preservation (2/2/2/2) | Global Data Centres: CDDIS (NASA GSFC, USA), IGN (France), SIO (USA); Regional Data Centres (BKG Germany, Geoscience Australia, KASI South Korea) | Standardized Observation Logs (RINEX) |
| F4 — Technique Analysis Centre Processing | Geodetic Software and Tools (2/3/1/2); GNSS Data Processing and Analysis (4/4/3/4) — annex evidence indicates People maturity is uneven across centres, since succession planning is not formally documented for every Analysis Centre team; Knowledge Management (1/2/1/1) | 12+ independent IGS Analysis Centres (CODE, ESA/ESOC, GFZ, JPL, NGS, NRCan, GRGS, Wuhan University, etc.) | Uncombined Solutions & Normal Equations (SINEX) |
| F5 — Multi-Centre Orbit & Clock Combination (ACC/SPOCC) | Risk Management (1/1/0/0); Knowledge Management (1/2/1/1); Disaster Recovery and Supply Chain Continuity (2/2/1/0); Performance Management (2/2/0/0); Geodetic Data Products (2/3/3/3) | Analysis Centre Coordinator (ACC): Geoscience Australia and NASA GSFC, joint leadership for the 2025–2028 term[^acc-transition]. Combination software (SPOCC): GFZ, Germany | Integrated Multi-Technique Solution (SP3 orbits, CLK clocks) |
| F6 — Orbit Validation & Independent SLR Quality Assurance | SLR Data Acquisition and Storage (2/4/3/3); Regulatory Compliance (3/3/3/3); Standards Development and Promotion (3/3/3/3) | ILRS network and Analysis Centres (NASA GSFC, ASI Italy, GFZ Germany), coordinated with the IGS Orbit Quality Working Group | Validated Orbit Products & SLR Residual Reports |
| F7 — Global Product Dissemination & Real-Time Streaming | Data Distribution (2/2/1/3); Geodetic Services (2/2/2/2) | IGS Central Bureau (NASA JPL & GSFC, USA), CDDIS (USA), BKG (Germany), IGN (France); Real-Time Service NTRIP casters concentrated at BKG and CDDIS[^agy-validation] | Published Ephemerides & Clock Biases (SP3, CLK, BIA, SSR streams) |
4. International Terrestrial Reference Frame (EGV Level 3)
Workflow document: ITRF Workflow (Work Assignment 2 Annex, v5.0)
The ITRF is the fundamental coordinate reference system of global geodesy — the Level 3 EGV realisation of the Global Reference Frames product, combining observations from GNSS, VLBI, SLR, and DORIS across a global multi-technique network. It provides the stable three-dimensional coordinate system upon which satellite navigation, Earth observation, sea-level monitoring, and all other geodetic applications depend. The ITRF is produced by the ITRS Product Center at IGN (France) using the CATREF software suite under the governance of the IERS Directing Board.
The workflow comprises nine functions, F1 through F9.[^agy-validation] Local ties (F2) are one of the largest systematic error sources in ITRF realisation; VLBI correlation (F5) is a distinct, severely constrained computing bottleneck sitting upstream of technique analysis. The critical organisational bottleneck is F7 — ITRS Combination at IGN — a small team operating proprietary software with no formal backup mandate and no documented succession plan for the combination process itself.
Functions, Capabilities, Organisations and Information Artifacts
| Function | Capabilities (People / Process / Technology / Data) | Organisation(s) | Information Artifact |
|---|---|---|---|
| F1 — Multi-Technique Ground Tracking | Ground-Based Asset Management (3/2/2/3); Equipment Calibration and Maintenance (4/3/3/0); SLR Data Acquisition and Storage (2/4/3/3); VLBI Data Acquisition and Storage (3/3/3/3); GNSS Data Acquisition and Storage (4/4/3/3); DORIS Data Acquisition and Storage (4/4/4/4) | Globally distributed GNSS/VLBI/SLR/DORIS stations under national mapping/space agencies, coordinated by IGS, IVS, ILRS and IDS | Raw Observational Data |
| F2 — Co-Location Local Tie Surveys | Local Tie (2/2/1/3) | National survey authorities and mobile survey teams (IGN France and national geodetic agencies) operating at ~107 co-location Core Sites | Local Tie Survey Vectors & SINEX Files |
| F3 — First-Mile Telemetry & Data Transport | Network Operations (2/2/1/3) | National research/education networks and station operators — e-VLBI broadband, GNSS real-time push, SLR/DORIS scheduled uploads | Transported Multi-Technique Data Streams |
| F4 — Global Archiving & Synchronization | Data Quality Management (2/2/1/3); Metadata Management (2/2/1/3); Data Preservation (2/2/2/2) | Global Data Centres: CDDIS (NASA GSFC, USA), IGN (France), SIO (USA) — two jurisdictions | Standardized Observation Logs (RINEX, CRD, vgosDB) |
| F5 — VLBI Correlation & Delay Extraction | Geodetic Software and Tools (2/3/1/2) | Washington Correlator (NASA GSFC/USNO, USA), Bonn Correlator (MPIfR/BKG, Germany), Haystack (USA) | Correlated Interferometric Observables (vgosDB delay & delay rate) |
| F6 — Intra-Technique Analysis | VLBI Data Processing and Analysis (2/2/2/3); SLR Data Processing and Analysis (3/4/3/4); GNSS Data Processing and Analysis (4/4/3/4); DORIS Data Processing and Analysis (4/4/3/4); Local Tie Processing and Analysis (2/3/1/2) | Technique services: IGS, IVS, ILRS, IDS analysis centres | Uncombined Solutions & Normal Equations (SINEX) |
| F7 — ITRS Combination & Stacking (IGN/CATREF) | Knowledge Management (1/2/1/1); Local Tie Processing and Analysis (2/3/1/2); Geodetic Data Products (2/3/3/3); Reference Frames (3/3/3/3) | ITRS Product Centre: IGN, France, using the CATREF software suite; governed by the IERS Directing Board | Integrated Multi-Technique Solution (ITRF Solution) |
| F8 — Independent Cross-Validation | Regulatory Compliance (3/3/3/3) | DGFI-TUM (Munich, Germany — DTRF) and NASA JPL (USA — JTRF); parallel independent combinations, not operational backups | Validated Multi-Centre Solutions & Inter-Comparison Reports |
| F9 — Formal Designation & Dissemination | Data Distribution (2/2/1/3); Geodetic Services (2/2/2/2) | IERS Directing Board (formal adoption); distribution via IGN and IERS Central Bureau (BKG, Germany) | Published ITRF Solution |
5. Earth Orientation Parameters (EGV Level 3)
Workflow document: EOP Workflow (Work Assignment 2 Annex, v5.0)
The EOP supply chain produces the fundamental transformation parameters linking the International Terrestrial Reference System (ITRS) to the International Celestial Reference System (ICRS). Four sub-products — Celestial Pole Offset (CPO), Universal Time (UT1), Length of Day (LOD), and Polar Motion (PM) — are delivered on two product tracks: a rapid daily series (Bulletin A, USNO) for space operations, and a monthly final series (Bulletin B / IERS C04, SYRTE) for geodetic combination. The EOP pipeline is structurally dependent on VLBI as the sole technique capable of determining UT1 — there is no observational alternative.
The workflow comprises nine functions, F1 through F9, with F7 split into two parallel, non-substitutable product tracks, F7a and F7b.[^agy-validation] VLBI correlation (F4) is a distinct, severely constrained computing bottleneck that directly affects the latency of the Rapid Service product space operations depend on. USNO's rapid track (F7a) and SYRTE's definitive track (F7b) are each independently single-institution, single-jurisdiction operations — the two most organisationally exposed functions in this workflow.
Functions, Capabilities, Organisations and Information Artifacts
| Function | Capabilities (People / Process / Technology / Data) | Organisation(s) | Information Artifact |
|---|---|---|---|
| F1 — Space Geodetic Multi-Technique Observation | Ground-Based Asset Management (3/2/2/3); Equipment Calibration and Maintenance (4/3/3/0); SLR Data Acquisition and Storage (2/4/3/3); VLBI Data Acquisition and Storage (3/3/3/3); GNSS Data Acquisition and Storage (4/4/3/3); DORIS Data Acquisition and Storage (4/4/4/4) | Global VLBI/GNSS/SLR/DORIS network (see workflow annex) | Raw Observational Data |
| F2 — First-Mile Telemetry & Transmission | Network Operations (2/2/1/3) | Station-to-correlator/data-centre transmission — e-VLBI broadband for time-critical Intensive sessions, GNSS/SLR/DORIS automated push | Transported Observational Data |
| F3 — Primary Archiving & Synchronization | Data Quality Management (2/2/1/3); Metadata Management (2/2/1/3); Data Preservation (2/2/2/2) | Global Data Centres: CDDIS (NASA GSFC, USA), IGN (France), SIO (USA) | Standardized Observation Logs (vgosDB, RINEX) |
| F4 — VLBI Correlation & Fringe-Fitting | Geodetic Software and Tools (2/3/1/2) | Washington Correlator (NASA GSFC, USA), Bonn Correlator (Max Planck Institut für Radioastronomie, Germany) | Correlated Interferometric Observables (vgosDB delay & delay rate) |
| F5 — VLBI Technique Analysis (UT1/CPO) | VLBI Data Processing and Analysis (2/2/2/3); Knowledge Management (1/2/1/1) | IVS analysis centres — sole technique for UT1, no observational alternative | Uncombined VLBI Solution (VLBI SINEX) |
| F6 — Satellite Geodetic Analysis (PM/LOD) | GNSS Data Processing and Analysis (4/4/3/4) | IGS/ILRS/IDS analysis centres | Uncombined Satellite Solutions (GNSS/SLR/DORIS SINEX) |
| F7a — Rapid Combination & Prediction (Bulletin A) | Risk Management (1/1/0/0); Performance Management (2/2/0/0); Geodetic Data Products (2/3/3/3); Reference Frames (3/3/3/3) — scored at the combination step overall, not yet separately assessed per track | USNO (USA), IERS Rapid Service/Prediction Center — single jurisdiction | Integrated Rapid Solution (Bulletin A) |
| F7b — Definitive Combination (Bulletin B / C04) | Risk Management (1/1/0/0); Performance Management (2/2/0/0); Geodetic Data Products (2/3/3/3); Reference Frames (3/3/3/3) — same PPTD basis as F7a; see note above | SYRTE, Observatoire de Paris, IERS Earth Orientation Centre (France) — single jurisdiction | Integrated Definitive Solution (Bulletin B / IERS C04) |
| F8 — Product Quality Assurance | (no State of Geodesy 2026 capability currently scored against this function — flagged as a coverage gap) | IERS Central Bureau (BKG, Germany) and IERS Directing Board — atmospheric/oceanic angular momentum (AAM/OAM) closure checks, frame-tie consistency verification | Quality-Assurance Validated EOP Series |
| F9 — Dissemination & User Access | Disaster Recovery and Supply Chain Continuity (2/2/1/0); Data Distribution (2/2/1/3) | IERS Central Bureau (Germany), USNO (USA), Paris Observatory (France) distribution infrastructure | Published EOP Series (Bulletin A, Bulletin B, IERS C04) |
6. International Celestial Reference Frame (EGV Level 3)
Workflow document: ICRF Workflow (Work Assignment 2 Annex, v5.0)
The ICRF is the quasi-inertial celestial reference frame defined by the precise positions of extragalactic radio sources (quasars), providing the inertial backdrop against which the ITRF is oriented and EOP are determined. The current realisation, ICRF3, was adopted by the IAU in 2018. Unlike other EGV products, the ICRF is an episodically produced scientific catalogue rather than a continuously updated operational product — it is reissued approximately once per decade. VLBI is the sole observational technique for ICRF maintenance; no redundant observational pathway exists.
The workflow comprises eight functions, F1 through F8.[^agy-validation] Correlation (F4) and archiving (F3) sit at two different NASA GSFC-hosted functions — a dual-hosting concentration worth reading as its own finding. F4 is the most organisationally exposed function in this workflow, reflecting a severe correlator throughput bottleneck; F3 carries a related single-archive concentration at CDDIS.
Functions, Capabilities, Organisations and Information Artifacts
| Function | Capabilities (People / Process / Technology / Data) | Organisation(s) | Information Artifact |
|---|---|---|---|
| F1 — Astrometric & Geodetic VLBI Observations | Ground-Based Asset Management (3/2/2/3); VLBI Data Acquisition and Storage (3/3/3/3); Equipment Calibration and Maintenance (4/3/3/0) | ~40 radio telescopes under IVS — sparse southern hemisphere coverage (see workflow annex) | Raw Observational Data |
| F2 — Raw Data Logistics & Telemetry | Network Operations (2/2/1/3) | Physical disk courier shipping (Mark 6 disk packs) and e-VLBI electronic transfer, dual-path | Transported Interferometric Data Streams & Disk Shipments |
| F3 — Primary Archiving & Metadata Registration | Data Quality Management (2/2/1/3); Data Preservation (2/2/2/2) | Archiving concentrated at CDDIS (NASA GSFC, USA), supported by BKG (Germany) | Standardized Observation Logs (vgosDB) |
| F4 — Interferometric Correlation & Fringe-Fitting | Geodetic Software and Tools (2/3/1/2) | Fewer than ten active IVS-affiliated correlators globally: Washington (NASA GSFC, USA), Bonn (Max Planck Institut für Radioastronomie, Germany), Haystack (USA) | Correlated Interferometric Observables (vgosDB delay & delay rate) |
| F5 — Astrometric VLBI Analysis | Knowledge Management (1/2/1/1); Geodetic Software and Tools (2/3/1/2); Training and Education (2/1/2/—); VLBI Data Processing and Analysis (2/2/2/3) | Fewer than 10 active IVS analysis centres for ICRF | Uncombined Celestial Catalogues & Normal Equations |
| F6 — ICRS Multi-Catalogue Combination | Geodetic Data Products (2/3/3/3); Reference Frames (3/3/3/3); Research and Development Prototyping (3/3/3/3) | IERS ICRS Centre, co-hosted at Observatoire de Paris/SYRTE (France) and BKG (Germany), under the IAU Working Group on the ICRF | Integrated Celestial Reference Frame Solution (Combined ICRF Solution) |
| F7 — Astrophysical Source Structure & Validation | Standards Development and Promotion (3/3/3/3) | Bordeaux Observatory (France), USNO (USA), IAU Commission A1/A2 — radio source structure and optical Gaia cross-validation | Validated Source Stability Indices & Gaia-VLBI Offset Reports |
| F8 — Formal IAU Designation & Dissemination | Data Distribution (2/2/1/3); Geodetic Services (2/2/2/2); Regulatory Compliance (3/3/3/3) | IAU General Assembly (formal adoption); CDS Strasbourg (France) and IERS ICRS Centre for publication | Published ICRF Catalogue (ICRF3) |
7. Global Earth Gravity Field (EGV Level 3)
Workflow document: Global Gravity Model Workflow (Work Assignment 2 Annex, v5.0)
The Global Earth Gravity Field supply chain produces Global Gravity Field Models (GGM) — mathematical representations of the Earth's gravitational potential as spherical harmonic series. These models define the geoid, the physical reference surface for all global height measurements, and are the prerequisite for unified global height systems under UN General Assembly Resolution 69/266. The supply chain bifurcates between satellite gravimetry (GRACE-FO, GOCE) providing long-wavelength global coverage and surface gravimetry providing high-resolution short-wavelength detail; both streams must be combined to produce operational models. The absence of a confirmed successor to GRACE-FO represents a mission-continuity risk that, if realised, would degrade time-variable gravity monitoring for all downstream EGVs including Terrestrial Water Storage and Ice Sheets.
The workflow comprises nine functions, F1 through F9.[^agy-validation] The pipeline runs two organisationally distinct combination services on different cadences: COST-G's operational monthly time-variable combination (F5, hosted at AIUB Bern), and the decade-scale static ultra-high-degree combination (F7, NGA/GFZ/TU Munich) — with materially different institutional redundancy. Several capability scores below are shared across a satellite/surface or F7-adjacent split that the State of Geodesy 2026 baseline has not yet separately assessed; each is flagged where it applies. F7 is the most organisationally exposed function in this workflow, reflecting a critically small pool of professionals capable of gravity processing and static geoid model development.
Functions, Capabilities, Organisations and Information Artifacts
| Function | Capabilities (People / Process / Technology / Data) | Organisation(s) | Information Artifact |
|---|---|---|---|
| F1 — Satellite Gravimetry Mission Operations | Ground-Based Asset Management (3/2/2/3); Equipment Calibration and Maintenance (4/3/3/0); Gravity Data Acquisition and Storage (2/4/4/3) | Joint NASA (USA) / GFZ (Germany) mission operations — GRACE-FO has no confirmed successor mission | Raw Satellite Telemetry & Level-1a Data |
| F2 — Terrestrial, Airborne & Marine Acquisition | Ground-Based Asset Management (3/2/2/3); Equipment Calibration and Maintenance (4/3/3/0); Gravity Data Acquisition and Storage (2/4/4/3) — same PPTD basis as F1, not yet separately assessed per stream | National mapping/geological agencies, naval authorities, airborne survey operators and commercial firms worldwide — severe coverage gaps, esp. Africa, South America, oceans | Raw Terrestrial/Airborne/Marine Gravity Observations |
| F3 — Dual-Stream Archiving & Collation | Data Quality Management (2/2/1/3); Data Preservation (2/2/2/2); Data Sharing (3/4/2/3) | Satellite: PO.DAAC (NASA JPL, USA) / GFZ ISDC (Germany). Surface: Bureau Gravimétrique International (BGI, France) | Standardized Observation Logs & Anomaly Datasets |
| F4 — Satellite Gravity Processing (Level-2) | Training and Education (2/1/2/—); Geodetic Software and Tools (2/3/1/2); Gravity Data Processing and Analysis (3/3/2/3) | GRACE-FO Science Data System: CSR/University of Texas (USA), NASA JPL (USA), GFZ (Germany) | Uncombined Satellite Gravity Solutions (Monthly Level-2 coefficients) |
| F5 — Time-Variable Gravity Combination (COST-G) | (no State of Geodesy 2026 capability currently scored against this function — flagged as a coverage gap) | Combination Service for Time-variable Gravity Fields (COST-G), hosted at AIUB (Bern, Switzerland), under IAG/IGFS[^cost-g] | Integrated Time-Variable Gravity Solutions |
| F6 — Surface Gravity Anomaly Harmonization | Training and Education (2/1/2/—); Geodetic Software and Tools (2/3/1/2); Gravity Data Processing and Analysis (3/3/2/3) — same PPTD basis as F4, not yet separately assessed per stream | BGI (France), National Geospatial-Intelligence Agency (NGA, USA), national agencies | Global Surface Gravity Anomaly Grids |
| F7 — Ultra-High-Degree Global Combination | Research and Development Planning (2/1/2/1); Knowledge Management (1/2/1/1); Geodetic Data Products (2/3/3/3); Research and Development Prototyping (3/3/3/3) | NGA (USA), GFZ (Germany), TU Munich (Germany) — the only institutions currently capable of leading an EGM2008 successor | Integrated Multi-Technique Solution (Global Gravity Field Model) |
| F8 — Geoid Model Evaluation & Benchmark Validation | (no State of Geodesy 2026 capability currently scored against this function — flagged as a coverage gap) | IGFS/IAG Commission 2, national geodetic agencies, academic evaluation teams — comparison against GPS/levelling benchmarks and ocean mean dynamic topography (MDT) | Validated Geoid Models & Quality Assessment Dossiers |
| F9 — Model Archiving & Dissemination | Data Distribution (2/2/1/3); Geodetic Services (2/2/2/2); Data Sharing (3/4/2/3) | International Centre for Global Earth Models (ICGEM), hosted at GFZ Potsdam, Germany — single jurisdiction | Published Gravity Field Model (ICGEM) |
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Work Assignment 3 — Risk Assessment and Gap Analysis takes the function-level capability, organisation and artifact mapping in Sections 3–7 above and assesses it against the six Guiding Principles — identifying capability shortfalls and organisational dependencies, scoring and prioritising them, and developing the resulting investment case. That analysis is performed in Work Assignment 3 in full; this report deliberately stops at the mapping.
End of Work Assignment 2 Report
[^sog2026]: United Nations Global Geodetic Centre of Excellence, 2026, State of Geodesy 2026: A Baseline Maturity Assessment, Bonn, Germany, https://www.un.org/globalgeospatial/sites/default/files/2026-05/stateofgeodesy.pdf [^acc-transition]: Spatial Source, 2025, Geoscience Australia, NASA GSFC to act as IGS ACC, https://www.spatialsource.com.au/geoscience-australia-nasa-gsfc-to-act-as-igs-acc/ — confirms Geoscience Australia and NASA Goddard Space Flight Center as joint leads for the new ACC term, supported by GFZ and MIT; corroborated by NASA Goddard's own announcement, https://earth.gsfc.nasa.gov/geo/projects/sgp/updates/new-igs-analysis-center-coordinator-announced
[^agy-validation]: External research validation pass, September 2026, re-deriving per-product function granularity and cross-checking ownership/risk findings against primary coordinating-service sources — full findings and per-claim source lists in the external validation research findings. Findings are carried here as Asserted per this document's evidence-status convention (Work Assignment 1) pending independent verification of each specific claim, not as TPWG-confirmed findings; two specific figures in that research pass (a Kokee Park–Wettzell Intensive-session percentage, and a blended JPL workforce-reduction percentage) could not be independently verified and are corrected or omitted here rather than restated.
[^jpl-layoffs]: Washington Post, 12 November 2024, NASA Jet Propulsion Laboratory lays off 5 percent of workforce; Space.com, NASA's Jet Propulsion Lab laying off 5% of its workforce (November 2024, ~325 employees); Universe Today, NASA's JPL Lays Off Another 325 People — reporting three distinct 2024–2025 rounds (~8% February 2024, ~530 employees; ~5% November 2024, ~325 employees; ~11% October 2025, ~550 employees), not a single blended figure.
[^jpl-wildfire]: Space.com and SpaceNews, January 2025, reporting on JPL's closure during the Eaton Fire (Los Angeles County wildfires): mandatory evacuation zone from 8 January 2025, facility closed with work-from-home extended through 17 January 2025 — approximately nine to ten days' disruption, not independently confirmed at a more precise figure.
[^genesis]: European Space Agency, GENESIS mission overview, https://www.esa.int/Applications/Satellite_navigation/Mapping_planet_Earth_for_better_positioning_ESA_s_GENESIS_mission — approved November 2022, targeting launch ~2028; first satellite to co-locate VLBI, GNSS, SLR and DORIS instrumentation in orbit, intended to contribute in-orbit space ties supporting future ITRF realisations.
[^icrf3]: Charlot, P., et al., 2020, "The third realization of the International Celestial Reference Frame by very long baseline interferometry (ICRF3)," Astronomy & Astrophysics, 644, A159; International Astronomical Union, 2018, Resolutions of the XXXth IAU General Assembly, Resolution B2 on ICRF3.
[^cost-g]: Jäggi, A., et al., 2020, "COST-G: The International Combination Service for Time-variable Gravity Fields," Advances in Geosciences, 50, 45–54.
[^grace-c]: NASA/DLR GRACE-C mission planning and the proposed ESA/NASA MAGIC (Mass Change and Geosciences International Constellation) — both publicly announced mission concepts targeted for the late 2020s; neither is operational as of this report, and specific launch-date commitments should be confirmed directly with NASA/ESA before being treated as settled.