Turkish National Geodesy Commission 25th Symposium, 2026 — Sessions and Topics

The symposium comprises four main sessions, structured in parallel with the TUJK working groups and with the commission structure of the International Association of Geodesy (IAG), together with a cross-cutting theme session. Authors are expected to select a session when submitting their abstract; the Organizing Committee reserves the right to reassign a contribution to another session in the interest of the scientific program's coherence.

Session 1: Reference Coordinate Systems and Frames

This session covers the definition, realization, improvement and maintenance of terrestrial, celestial and vertical reference systems and frames, together with the combination of the space-geodetic techniques on which these frames rely. Contributions focusing on positioning methods and applications are considered under Session 4.

International, regional and national terrestrial coordinate reference systems/frames
The International Celestial Reference System/Frame
International, regional and national vertical coordinate reference systems/frames
Establishment, realization and improvement of geodetic reference systems
Space-geodetic techniques contributing to frame realization (VLBI, SLR, DORIS, GNSS) and technique combination
Co-location on the ground and in space, and local tie measurements
Continuously operating observation networks based on satellite/space geodesy, and the sustainability of the observing infrastructure
Kinematic and deformable reference frames, time-dependent coordinates and datum transformations
The contribution of new-generation GNSS signals, multi-constellation solutions and LEO-PNT to reference frames
The Global Geodetic Reference Frame (GGRF) and the United Nations GGIM processes
Cooperation with international services related to satellite/space geodesy and reference coordinate systems (IERS, IGS, ILRS, IVS, IDS, EUREF, etc.)
…and other topics related to reference coordinate systems

Session 2: Gravity Field

This session covers the measurement and modeling of the Earth's gravity field and the monitoring of its temporal variations, the determination of the geoid and the vertical datum, and studies on sea level, satellite altimetry and hydrogeodesy.

Terrestrial, marine, airborne and satellite gravimetry
Quantum (cold-atom) gravimeters and gravity gradiometers
Global, regional and local gravity field modeling
Temporal variations of the gravity field
Time-variable global gravity field models and their applications in the Earth and atmospheric sciences
Next-generation gravity satellite missions and future mission concepts
Geoid determination and machine-learning-based approaches to geoid modeling
National geoid and vertical datum studies, and the International Height Reference System/Frame (IHRS/IHRF)
Chronometric leveling with optical clocks, and relativistic geodesy
Sea level variations, tide gauge measurements and tide gauge–GNSS integration
Determination of sea surface topography
Satellite radar altimetry and its applications
Hydrogeodesy and the monitoring of continental water mass variations
Bathymetric studies
Precise orbit determination (POD)
…and other topics related to the gravity field

Session 3: Earth Rotation and Geodynamics

This session covers the interactions between the Earth's rotation and the solid Earth, the oceans, the atmosphere and the hydrosphere, as well as the geodetic determination and geoscientific interpretation of crustal deformation arising from natural processes. Method- and application-oriented contributions on the deformation monitoring of engineering structures and geodetic networks are considered under Session 4.

Tectonic motions and the associated crustal deformation
The earthquake cycle: interseismic, coseismic and postseismic deformation, and slow slip events
Monitoring of volcanic deformation
Geodetic monitoring of land subsidence caused by groundwater extraction, and of landslide movements
Earth rotation, Earth rotation parameters (ERP) and polar motion
The effect of mass redistribution on the Earth's rotation and shape
The effects of fluid layers — atmosphere, ocean and hydrosphere — on the Earth, and loading-induced deformation
Tides and tidal models
Cryospheric change and glacial isostatic adjustment (GIA)
The use of InSAR, LIDAR and similar emerging technologies in studies of tectonics and crustal deformation
Cloud-based processing of large InSAR/GNSS datasets, and machine learning approaches in deformation analysis
The use of geodetic data in earthquake early warning and rapid source parameter determination
Planetary geodesy and planetary dynamics
…and other topics related to Earth rotation and geodynamics

Session 4: Positioning and Applications

This session covers terrestrial and satellite-based positioning systems, methods and services; navigation; engineering and industrial applications; and the integration of geodetic data and products with other disciplines.

Terrestrial and satellite/space-based positioning systems and methods
PPP, PPP-RTK, network RTK and cloud-based positioning services
LEO-PNT and integrated PNT architectures
Indoor and outdoor positioning
Navigation and multi-sensor integration (GNSS/INS, etc.)
Positioning applications with unmanned ground, aerial, and marine vehicles
GNSS jamming and spoofing, and resilient PNT solutions
Time and frequency transfer
Laser and radar interferometry applications (SAR, InSAR, etc.)
Deformation monitoring and deformation analysis in three-dimensional geodetic networks
Monitoring of engineering structures, and the application of geodesy to engineering works
Atmospheric research using satellite/space geodetic methods (troposphere, ionosphere, space weather)
GNSS reflectometry (GNSS-R) and signals-of-opportunity sensing
Spatial data and geodetic applications in polar regions
Integration of geodetic data and products with geographic information systems, and development of the geodetic infrastructure of GIS
Positional infrastructure for digital twins, smart cities and autonomous systems
…and other topics related to positioning and applications