The GGOS 2020 Recommendations

The recommendations of the GGOS 2020 Writing Team are numbered, with the first number indicating the chapter from which a recommendation originates.

Recommendation 1.1 (Transition from research to operational):

Recognizing that
geodesy has a large potential to help meet the challenge in reaching sustainable development for a global society on a changing planet,
it is recommended that
IAG and GGOS engage in improving the framework conditions for fully harnessing the potential of geodesy for Earth observation by actively promoting a transition of the geodetic observing system from research to operational, and facilitate the establishment of an operational core of GGOS with sufficient human resources for the sustained operation of this core.

Status: Not implemented yet.

Recommendation 1.2 (Global reference systems):

Recognizing that
the global geodetic reference frames are fundamental for all Earth observations,
it is recommended that
IAG and GGOS facilitate, particularly in the frame of GEO, international agreement on a global geodetic reference system.

Status: Not implemented yet.

Recommendation 1.3 (Outreach and Eduction):

Recognizing that
society to a large extent is not aware of the vital role played by geodesy for realizing the principle of sustainable development, and that
educational aspects are extremely important (because they have the greatest impact on societal behavior) in order to prepare future generations to make use of the full benefits of geodesy,
it is recommended that
IAG and GGOS make dedicated outreach efforts to science and society at large, with the goal to promote geodesy's role in reaching sustainable development, and to integrate this role of geodesy appropriately into education programs.

Status: Not implemented yet.

Recommendation 2.1 (Adherence to conventions and standards):

Recognizing that
consistency within and across the "three pillars of geodesy" crucially depends on well-defined standards and widely respected conventions,
it is recommended that
IAG continue to maintain geodetic standards and develop conventions for geodetic analyses and products, and that
every effort be made by the IAG Services and GGOS to adhere to relevant standards and conventions.

Status: Not implemented yet.

Recommendation 3.1 (Towards new reference systems):

Recognizing that
the combination of geodetic measurements will require new definitions of a terrestrial reference system and a consistent realization of this system,
it is recommended that
particular attention be paid in GGOS to the development of these new reference systems.

Status: Not implemented yet.

Recommendation 4.1 (Promotion of ITRS and maintenance of ITRF):

Recognizing that
a stable and accurate geodetic reference frame must underpin Spatial Data Infrastructures (SDI), to ensure that all geo-referenced data used by a wide range of community groups and government agencies is unambiguously linked to the geodetic foundation,
it is recommended that
ITRS be employed as the global geodetic reference system for SDI, and that
the ITRF be maintained and made accessible with an operational core ensuring ITRF with the accuracy, long-term stability, and the level of accessibility required by SDI applications.

Status: Not implemented yet.

Recommendation 4.2 (The link between science and applications):

Recognizing that
geodesy plays a vital role with respect to sustainable development, the provision of community services, support for many vital industries, security and emergency management, mapping and navigation, and others,
it is recommended that
the link between "scientific geodesy" and "practical (or operational) geodesy" be strengthened, and made explicit so that national geodetic agencies are reminded of the mutual benefits of these two parts of geodesy, and of the fundamental contribution of geodesy to their mission.

Status: Not implemented yet.

Recommendation 4.3 (Links of IAG to other professional organizations):

Recognizing that
geodesy and GGOS are relevant to a number of international and national scientific and professional sister organizations of IAG, including, but not restricted to ISPRS, FIG, IAIN, IEEE, and IUGG,
it is recommended that
the IAG continue to work closely with these organizations by promoting the GGOS vision and its activities.

Status: Not implemented yet.

Recommendation 4.4 (Embracing new technologies):

Recognizing that
there is rapid technological development integrated into professional applications of geodesy,
it is recommended that
GGOS embrace new geoinformation/geodetic technologies such as DInSAR, LIDAR, GNSS-RTK, structural monitoring systems, and multi-sensor precision navigation systems, in an integrated manner to address different spatial and temporal user requirements for high accuracy geometric information that is unambiguously tied to a rigorous geodetic framework.

Status: Not implemented yet.

Recommendation 5.1 (Representation in Earth Observation Committees):

Recognizing that
geodesy provides the metrological basis enabling Earth observation with the required accuracy and that
the global geodetic reference frame is a fundamental contribution to global Earth observation,
it is recommended that
GGOS maintain a formal representation in existing Earth observing coordination committees (international bodies and commissions), and establish links to relevant committees as appropriate.

Status: Not implemented yet.

Recommendation 5.2 (Real-time access to data of GNSS tracking stations and promotion of occultation receivers):

Recognizing that
real-time or low-latency access to geodetic observations, in particular GNSS observations, is increasingly important for applications in numerical weather predictions, space weather predictions, early warning systems, and other societal applications,
it is recommended that
existing and future ground-based GNSS sites installed by geodesists be connected in real-time to GNSS data and analysis centers thus enabling these non-geodetic applications, and that
future geodesy missions using GNSS receivers be radio occultation-compatible, whenever possible, and that
a framework be established to allow occultation data processing as a service to geodesy missions (i.e., outside the geodesy missions themselves).

Status: Not implemented yet.

Recommendation 5.3 (Gravity field and circulation models):

Recognizing that
detailed knowledge of the Earth's gravity field is important for atmosphere and ocean circulation models,
it is recommended that
that GGOS establish proper contacts and interfacing to the Earth system modeling community with the goal to enable improvements of the gravity field representation in circulation models.

Status: Not implemented yet.

Recommendation 5.4 (GNSS and climate studies):

Recognizing that
GNSS observations are an important information source for climate studies related to water vapor,
it is recommended that
GGOS (through its components) continue archiving GNSS observations and all necessary data for future reprocessing and use in climate studies, and that
long-term funding for this archiving be secured from relevant climate programs.

Status: Not implemented yet.

Recommendation 5.5 (GGOS and monitoring of the global water cycle):

Recognizing that
geodetic observations are fundamental for monitoring the global hydrological cycle on global to local scales,
it is recommended that
GGOS encourage and support a global water cycle service that provides information on changes in the water storage on land, in ice sheets and in the oceans on a routine basis, potentially through assimilation of the geodetic observations in a Earth system model.

Status: Not implemented yet.

Recommendation 5.6 (GNSS seismology):

Recognizing that
GNSS can potentially contribute to the near real-time determination of the seismic magnitude and associated displacement field of large earthquakes,
it is recommended that
GGOS promote the development of GNSS seismology, particularly for early warning and disaster assessment purposes.

Status: Not implemented yet.

Recommendation 6.1 (GGOS in support of planetary missions):

Recognizing that
planetary geodesy, radio science, interferometry (including imaging VLBI, astrometric VLBI, and Earth-Space VLBI), and interplanetary navigation all require an accurate geodetic foundation, and that
although the performance of GGOS is not a limiting factor in all of these applications, future requirements will be more demanding, especially those imposed by interplanetary navigation, and in some cases exceeding presentday capabilities of GGOS,
it is recommended that
GGOS be developed in order to meet these future requirements, that in particular
GGOS generate real-time values of Earth orientation accurate to $\leq 3$ mm, and that
GGOS enable calibrations of troposphere delay and ionosphere accurate to < 3 mm and < 2 TEC units, respectively}

Status: Not implemented yet.

Recommendation 7.1 (Threshold and target values for GGOS):

Recognizing that
it will not always be possible to implement the observing system meeting all observational requirements,
it is recommended that
GGOS set up, together with relevant user groups, threshold and target values in terms of accuracy, spatial and temporal resolution, latency, and integrity, for the quantities to be observed or derived from geodetic observations.

Status: Not implemented yet.

Recommendation 7.2. (GGOS database of user needs and observational requirements):

Recognizing that
the user needs and observational requirements with respect to geodetic observations and products will evolve over time,
it is recommended that
GGOS maintain a database of user needs and observation requirements, and a list of products to be provided by GGOS in order to meet these evolving requirements.

Status: Not implemented yet.

Recommendation 7.3 (Improved access to ITRF):

Recognizing that
the global geodetic reference frame and ready access to this frame plays a crucial role for many scientific, professional and societal applications,
it is recommended that
GGOS focus on improved access to the global reference frame with low latency and high spatial resolution as well as the long-term stability of the frame.

Status: Not implemented yet.

Recommendation 8.1 (Future reference frame approach based on extended model):

Recognizing that
users in many applications increasingly require access to a geodetic reference frame with high spatial and temporal resolution in order to be able to detect "anomalous" motion of an object with respect to the reference frame,
it is recommended that
GGOS encourage the development of a future reference frame approach based on a reference frame model with, in principle, infinite spatial and temporal resolution, and that
this reference frame be based on a dynamic Earth system model that assimilates observations and predicts the motion of all points on the surface of the Earth, as well as variations in the gravity field of the Earth system and the rotation of the solid Earth.

Status: Not implemented yet.

Recommendation 8.2 (Towards an integrated Earth system model):

Recognizing that
the future geodetic reference frame approach, in order to meet the demanding user requirements and to achieve the required spatial resolution, will have to be based on model prediction,
it is recommended that
GGOS promote the development of an integrated Earth system model which can be used to predict the geodetic quantities in a self-consistent framework, and that
both forward-modeling and inversion methods be developed to predict geodetic quantities and to invert geodetic observations for the forcings, respectively.

Status: Not implemented yet.

Recommendation 9.1 (Augmentation of the current global geodetic infrastructure):

Recognizing that
the currently implemented global geodetic infrastructure is not sufficient to provide a monitoring of Earth's shape, gravity field and rotation meeting most of the users' needs, and to sustain the global geodetic reference frames required for many scientific and societal applications,
it is recommended that
the global geodetic infrastructure not only be maintained at the current level but also be augmented, in order to close major spatial and technological gaps, with: (1) a global network of core sites on all continents, (2) absolute and superconducting gravimeters at a global network of reference sites, in particular the core sites, and (3) two additional dedicated SLR satellites, that
an operational core system be built up and maintained with the necessary infrastructure for an operational geodetic Earth system service providing quantitative information on changes in ice sheets, sea level, water cycle, and climate, as well as for hazards, disasters, and resource management application, and that
the operational core include at least: (i) the global geodetic networks for the determination and monitoring of the geodetic reference frames, including Earth rotation, (ii) continuous gravity satellites missions for the monitoring of mass transport, (iii) continuous satellite missions for the monitoring of ice sheets, sea surface height, and lake level variations, and (iv) continuous satellite missions for the imaging of the solid Earth's surface.

Status: Not implemented yet.

Recommendation 10.1 (Continuation of the IAG Services):

Recognizing that
the terrestrial technique-specific entities represented by the IAG Services are the basis of IAG's GGOS, and that their products are prerequisites for the realization GGOS,
it is recommended that
the work of the technique-specific entities, based on the state-of-the-art observational and analysis tools, be continued, and that
funding for these technique-specific services be secured on a long-term basis.

Status: Not implemented yet.

Recommendation 10.2 (Uninterrupted sequence of satellite missions):

Recognizing that
uninterrupted geodesy-related satellite missions are required for the generation of the best possible time-varying gravity field, and the monitoring of sea and ice surface topographies, and that
today there is no consistent plan for deploying geodesy-related satellite missions,
it is recommended that
GGOS, in close partnership with the space agencies and CEOS, develops a plan for an uninterrupted series of geodesy-related space missions based on scientific and societal needs, and that
GGOS have a specific entity developing these scenarios.

Status: Not implemented yet.

Recommendation 10.3 (Continuation of IERS):

Recognizing that
the results of the technique-specific entities (the IAG Services) are compared, validated, and combined to generate unique, technique-independent geodetic products (celestial, terrestrial, and, to a lesser extent, gravitational reference frames, constants, etc.), that
this work is undertaken by the IERS for the geometry-related products,
it is recommended that
the work of the IERS be continued based on state-of-the-art validation and combination techniques, and that
funding for these activities be secured on a long-term basis.

Status: Not implemented yet.

Recommendation 10.4 (Plan for gravimetric mission-independent products):

Recognizing that
full utilization of the gravimetric satellite missions requires long time series based on all relevant techniques,
it is recommended that
the IGFS develop a plan to generate mission-independent gravity products, which also include terrestrial and airborne data, that
an entity realizing this plan (inside or outside the IGFS) be identified, or, if not existing, be created, and that
long-term funding for this entity be secured.

Status: Not implemented yet.

Recommendation 10.5 (Establishment of an IAS):

Recognizing that
the geodetic products resulting from space missions (including SLR data, terrestrial and airborne gravity measurements) must be compared, validated, and combined into unique geodetic products, which have to be, moreover, consistent with the geometry-related products, and that
an international altimetry service could address one aspect of this problem, namely that of sea and ice surface topography based on the data of all altimetry missions available,
it is recommended that
an IAS as a mission-independent altimetry service be established and incorporated into IAG and GGOS, and that
funding for this IAS be secured on a long-term basis.

Status: Not implemented yet.

Recommendation 10.6 (Establishment of an international InSAR Service):

Recognizing that
the InSAR observations are very versatile observations of Earth surface deformations and that
these observations serve a wide range of applications,
it is recommended that
an international InSAR service be established and incorporated into IAG and GGOS, that
this service support the application of InSAR integrated with GNSS and make products related to Earth surface deformations routinely available, and that
funding for this service be secured on a long-term basis.

Status: Not implemented yet.

Recommendation 10.7 (Standards and conventions):

Recognizing that
in order to ensure consistency of observations, data processing, modeling and products across the "three pillars of geodesy" at a level of better than \power{10}{-9}, adherence to geodetic standards and conventions is crucial,
it is recommended that
a GGOS entity responsible for the geodetic standards and conventions be created (known as the "GGOS Bureau of Standards and Conventions"), that
this entity keep track of and make available a detailed and concise list of geodetic conventions, constants, and procedures, and that
this catalogue include the IERS conventions.

Status: Not implemented yet.

Recommendation 10.8 (Networks and communication):

Recognizing that
currently there is a large number of more or less independent technique-specific ground-tracking networks (and products) in GGOS, and that
coordination of these networks is not sufficient,
it is recommended that
the IAG Services operating the technique-specific networks create, in cooperation with the IERS, a "GGOS Communications and Networks" entity with the objective of designing the networks (minimum number and distribution of core sites, co-location of techniques, etc.) and scoping the operation (communication and data flow between networks, and from stations to regional and global data centers) of the network as a whole.

Status: Not implemented yet.

Recommendation 10.9 (United Nations support for GGOS):

Recognizing that
the full implementation of GGOS, and particularly of an operational core system, requires broad international support for GGOS as organization,
it is recommended that
IAG continue its active role in GEO and other relevant organizations, and that
IAG and GGOS continue the dialog on the association of GGOS with an appropriate United Nations agency (e.g., UNESCO).

Status: Not implemented yet.

Recommendation 10.10 (Establishment of a GGOS Coordinating Office):

Recognizing that
GGOS is based on a wide range of contributing organizations, institutions, space agencies, services, and systems, and that
GGOS has a wide range of users and stakeholders,
it is recommended that
GGOS establish a central coordinating entity (known as the "GGOS Coordination Office") with the task to maintain an overview on GGOS contributors and users and their requirements as well as to support the GGOS decision-making entities on a day-to-day basis, and that
funding for this entity be secured on a long-term basis, preferably through the respective United Nations agency.

Status: Not implemented yet.

Recommendation AI.1 (GEO Resolution):

Recognizing that
the fundamental role for geodesy and the geodetic observation system for Earth observation in general, and GEO in particular, necessitates the continuous commitment of many national and regional institutions, organizations and governments to GGOS,
it is recommended that
the GEO Plenary consider a resolution recommending to the GEO member countries to maintain, and if necessary increase, their support of the operational infrastructure of GGOS at a level appropriate to meet the requirements of the SBAs addressed by GEO.

Status: Not implemented yet.

Recommendation AI.2 (GGOS Stakeholder Conference):

Recognizing that
the implementation of GGOS on the basis of the findings and recommendations resulting from the GGOS 2020 Process requires a continuous dialog engaging all stakeholders inside and outside of IAG,
it is recommended that
a conference of the GGOS stakeholder organizations be organized to further develop the findings and recommendations of the GGOS 2020 book into key elements for the Implementation Plan of GGOS, and that
the GGOS 2020 book serve as the basis for discussion and decisions at this conference.

Status: Not implemented yet.


Last edited 02 December 2016

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