Commission 4 – Positioning and Applications (2007-2011)

URL: http://www2.ceegs.ohio-state.edu/IAG-Comm4/

President: Sandra Verhagen (The Netherlands)
Vice President: Dorota Grejner-Brzezinska (USA)

Terms of Reference

To promote research into the development of a number of geodetic tools that have practical applications to engi-neering and mapping. The Commission will carry out its work in close cooperation with the IAG Services and other IAG Entities, as well as via linkages with relevant Entities within Scientific and Professional Sister Organi-sations.

Recognising the central role that Global Navigation Satel-lite Systems (GNSS) plays in many of these applications, the Commission’s work will focus on several Global Positioning System (GPS)-based techniques, also taking into account the expansion of GNSS with Glonass, Galileo and Beidoe. These techniques include precise positioning, but extending beyond the applications of reference frame densification and geodynamics, to address the demands of precise, real-time positioning of moving platforms.

Several Sub-Commissions will deal with precise kine-matic GNSS positioning technology itself (alone or in combination with other positioning sensors) as well as its applications in surveying and engineering. Recognising the role of continuously operating GPS reference station network, research into non-positioning applications of such geodetic infrastructure will also be pursued, such as atmospheric sounding. Thereby, other geodetic techni-ques such as VLBI will be considered as well.

The commission will also deal with geodetic remote sensing, using (differential) InSAR, and GNSS as a remote sensor with land, ocean and atmosphere applica-tions.


The main objectives of Commission 4 are:
  • Research into (integration of) new navigation and de-formation measurement / sensor technologies, and their applications.
  • Encourage research and development into new appli-cations in e.g. “precise navigation”, “geodetic remote sensing”, “engineering geodesy”.
  • Collaboration with geodetic organizations and services to promote and enable the use of GNSS and geodetic infrastructure for positioning as well as non-positioning applications.



  • SC 4.1: Multi-Sensor Systems
    President: Dorota Grejner-Brzezinska (USA)
  • SC 4.2: Applications of Geodesy in Engineering
    President: Günther Retscher (Austria)
  • SC 4.3: Remote Sensing and Modelling of the Atmosphere
    President: Marcelo Santos (Canada)
  • SC 4.4: Applications of Satellite and Airborne Imaging Systems
    President: Xiaoli Ding (Hong Kong)
  • SC 4.5: High-Precision GNSS
    President: Yang Gao (Canada)

Study Groups
  • SG 4.2: GNSS Remote Sensing and Applications
    Chair: Shuanggen Jin (South Korea)
  • SG 4.3: IGS Products for Network RTK and Atmo-sphere Monitoring
    Chair: Robert Weber (Austria)

Inter-Commission Working Groups
  • IC-WG1.1: Environment Loading – Modelling for Reference Frame and Positioning Applications
    Chair: Tonie van Dam (Luxembourg)

Inter-Commission Study Groups
  • IC-SG2: Quality of Geodetic Multi-Sensor Systems and Networks
    Chair: Hansjörg Kutterer (Germany)
  • IC-SG6: InSAR for Tectonophysics
    Chair: Masato Furuya (Japan)

Program of Activities
  • Interface with IAG sister organisations and other orga-nizations – e.g. FIG, ISPRS, IEEE, ION
  • Promote Geodesy and GGOS to a wide (professional) community
  • Offer outreach opportunity through its conferences and seminars (jointly organised with other organisa-tions)

Steering Committee
  • President: Sandra Verhagen (The Netherlands)
  • Vice-president: Dorota Grejner-Brzezinska (USA)
  • President SC 4.1: Dorota Grejner-Brzezinska (USA)
  • President SC 4.2: Günther Retscher (Austria)
  • President SC 4.3: Marcelo Santos (Canada)
  • President SC 4.4: Xiaoli Ding (Hong Kong)
  • President SC 4.5: Yang Gao (Canada)
  • Member-at-large: Pawel Wielgosz (Poland)
  • Representative of IAG Services: Ruth Neilan (USA)


SC 4.1 Multi-Sensor Systems
President: Dorota Grejner-Brzezinska (USA)
Vice-President: Naser El-Sheimy (Canada)
Secretary: Jinling Wang (Australia)

Terms of Reference

To coordinate research and other activities that address broader areas of multi-sensor system theory and applica-tions, with a special emphasis on integrated guidance, navigation, positioning and orientation of airborne and land-based platforms. The primary sensors of interest will be GNSS and inertial navigation systems; however the important role of other techniques used for indoor and pedestrian navigation environmental monitoring is also recognized. The Sub-commission will carry out its work in close cooperation with other IAG Entities, as well as via linkages with relevant scientific and professional organi-zations, such as ISPRS, FIG, IEEE, ION.

  • To follow the technical advances in navigation sensors and algorithms, including autonomous vehicle naviga-tion, based on
  • positioning sensors and techniques such as GPS (and pseudoliltes), INS, including MEMS IMU, wheel sensors, ultrasonic and magnetic sensors, and
  • positioning methods based on cellular networks and their hybrid with GPS
  • To follow the technical advances in mapping sensors, such as CCD cameras, laser range finders, laser scan-ners and radar devices
  • To standardize definitions and measurements of sensor related parameters
  • To study and report on the performance of stand alone and integrated navigation systems
  • To report on the development, possibilities and limita-tions of new multi-sensor system technologies.
  • To explore non-linear estimation and information fusion methods including artificial intelligence (AI), spectral estimation, parallel cascade identifiers, hybrid AI/KF modules and particle filters.
  • To facilitate extending the mobile mapping concept to environmental monitoring applications.
  • To stimulate new ideas and innovation in:
    • navigation algorithms, sensor calibration, synchro-nization and inter-calibration
    • real-time sensor information processing and geo-referencing
    • sensor and data fusion
    • automation techniques for information extraction from multi-sensor systems using expert systems
  • To study and monitor the progress in new applications (not limited to conventional mapping) of multi-sensor systems (transportation, engineering, car navigation, environmental monitoring personal navigation, indoor navigation, etc.)
  • To promote research collaboration and to organize and to participate in professional workshops, semi-nars, meetings
  • To promote research and collaboration with countries with no or limited access to modern multi-sensor tech-nology

To establish a web page providing information on the SC 4.1 activities, technology updates, and professional meet-ing calendar.

Working Groups

WG 4.1.1 Alternative Integration Algorithms

Chair: Aboelmagd Noureldin (Canada)

Terms of Reference

This working group will focus on developing new methods to replace traditional Kalman filtering (KF) techniques and improves positioning accuracy, especially when using low cost inertial sensors. The “Alterative Inte-gration Algorithms” WG will explore non-linear esti-mation and information fusion methods including artifi-cial intelligence (AI), spectral estimation, parallel cascade identifiers, hybrid AI/KF modules and particle filters. We will target applications related to land vehicles and air-borne navigation.

WG 4.1.2 Indoor Navigation Systems

Chair: Günther Retscher (Austria)

Terms of Reference

To promote research and development in the area of in-door navigation using systems, such as WiFi (Wireless Fidelity), UWB (Ultra-wide Band) and RFID (Radio Fre-quency Identification) in combination with dead reckon-ing (DR) sensors including micro-electro-mechanical systems (MEMS) inertial systems and other low cost posi-tioning sensors; and to integrate these location tech-nologies with GNSS. To report progress on multi-sensor integration and fusion technologies for an optimal esti-mation of a current users’ location and to develop new self calibration techniques for DR based on fuzzy logic and artificial intelligence.

WG 4.1.3 Multi-Sensor Systems for Environmental Monitoring Applications

Chair: Jan Skaloud (Switzerland)

Terms of Reference

This working group investigates several topics that facili-tate extending the mobile mapping concept to environ-mental monitoring applications. The primary goals are:
  • Adaptation of mobile mapping platforms for optimal monitoring on highly inclined terrain (e.g. cliffs, ava-lanches, landslides debris flow, etc.)
  • Introduction of rigorous quality measures into digital terrain models (DTM) derived from multi-sensor mobile platforms.
  • Revision of integrity measures used in direct georefer-encing of multi-sensor platforms.

SC 4.2 Applications of Geodesy in Engineering

President: Günther Retscher (Austria)
Vice-President: Gethin Roberts (UK)
Secretary: Michaela Haberler-Weber (Austria)

Terms of Reference

Rapid developments in engineering, microelectronics and the computer sciences have greatly changed both instru-mentation and methodology in engineering geodesy. To build higher and longer, on the other hand, have been key challenges for engineers and scientists since ancient times. Now, and for the foreseeable future, engineers con-front the limits of size, not merely to set records, but to meet the real needs of society minimising negative envi-ronmental impact. Highly developed engineering geodesy techniques are needed to meet these challenges. The SC will therefore endeavour to coordinate research and other activities that address the broad areas of the theory and applications of engineering geodesy tools. The tools range from conventional terrestrial measurement and align-ment technology (optical, RF, etc.), Global Navigation Satellite Systems (GNSS), geotechnical instrumentation, to software systems such as GIS, decision support systems, etc. The applications range from construction engineering and structural monitoring, to natural phe-nomena such as landslides and ground subsidence that have a local effect on structures and community infra-structure. The SC will carry out its work in close coopera-tion with other IAG Entities, as well as via linkages with relevant scientific and professional organisations such as ISPRS, FIG, IEEE, ION.


  • To monitor research and development into new tech-nologies that are applicable to the general field of “engineering geodesy”, including hardware, software and analysis techniques.
  • To study advances in dynamic monitoring and data evaluation systems for buildings and other manmade structures.
  • To study advances in monitoring and alert systems for local geodynamic processes, such as landslides, ground subsidence, etc.
  • To study advances in geodetic methods used on large construction sites.
  • To study advances in the application of artificial intelligence techniques in engineering geodesy.
  • To document the body of knowledge in this field, and to present this knowledge in a consistent frame work at symposia and workshops.
  • To promote research into several new technology areas or applications through the SC4.2 Working Groups.

Program of Activities
  • To study the technology and applications of engineer-ing geodesy in order to address the objectives for SC4.2 (Description see above).
  • To organize and to participate in professional work-shops, seminars, meetings, etc.
  • To establish a web page providing information on SC4.2 activities, professional meeting calendar, etc.

Working Groups

WG 4.2.1 Measurement Systems for the Navigation of Construction Processes
Chair: Wolfgang Niemeier (Germany)

Terms of Reference

To study and report the performance of the currently used navigation/guidance systems for construction machinery, and to promote the development of new methods and techniques for controlling construction processes.

WG 4.2.2 Dynamic Monitoring of Buildings
Chair: Gethin Roberts (UK)

Terms of Reference

To study and report the performance of currently used building monitoring systems, including techniques based on satellite and terrestrial measurements, and to promote the application of new sensor technology.

WG 4.2.3 Application of Artificial Intelligence in Engineering Geodesy
Chair: Alexander Reiterer (Austria)

Terms of Reference

To study and report on topics such as control of measurement- and guidance-systems, deformation analysis, control of alert systems, and the evaluation of their complex data stream through the use of Artificial Intelligence (AI) techniques (e.g. knowledge-based systems, genetic algorithms, artificial neural networks, etc.).

WG 4.2.4 Investigation of Kinematic and Dynamic Behaviour of Landslides and System Analysis
Chair: Gyula Mentes (Hungary)

Terms of Reference

Worldwide landslides are one of the major types of natural hazards killing or injuring a large number of individuals and creating very high costs every year. There has already been done a wide range of research work on landslides. Most of this work had a bias towards one discipline, like remote sensing or geology. The new idea of the working group is to promote multidisciplinary integra-tion of different methods. The main goal is to set up an integrated workflow for landslide hazard management.

SC 4.3 Remote Sensing and Modelling of the Atmosphere
President: Marcelo Santos (Canada)
Vice-President: Jens Wickert (Germany)
Secretary: Catherine Mitchel (Bath, UK)

Terms of Reference

The objective of Sub-Commission 4.3 (SC 4.3) is to co-ordinate research dealing with the treatment, interpreta-tion and modelling of measurements collected in the atmosphere for the purpose of improvements in geodetic positioning as well as for better understanding the atmo-sphere itself. Even though GNSS techniques are seen here as the primary research tools, other sensors also bring important information on the atmosphere and as such should be considered in the context of this Sub-Commis-sion.

Dedicated satellites, having on-board GNSS receivers, can also contribute to atmospheric studies by exploring the atmosphere-induced bending of GNSS signals while propagating through the atmosphere, to furnish round-the-clock weather data, monitor climate change, and improve space weather forecasts. Geodetic positioning can benefit and contribute to atmospheric models, such as Numerical Weather Prediction (NWP) models. Novel advancements in modelling the atmo-sphere as applied to positioning, error sources, instru-mentation, dedicated missions, and real- or near real-time data access should also be contemplated. SC4.3 will foster linkages with sister scientific and professional orga-nizations, such as IAG, ISPRS, FIG, IEEE and ION.

  • To explore the synergy that exists between Geodesy, meteorology and ionospheric sciences.
  • To encourage the processing of more and more LEO and also ground based data more and more also in near-real and/or real time.
  • To study the application of readily available data from numerical weather prediction models (data provision, assimilation techniques).
  • To study and suggest ways for homogenization of long term data set (e.g., some IGS stations since 1993) for climatologic investigations
  • To investigate the development and enhancement of the relatively new GNSS-based sounding techniques, e.g. neutral atmosphere / ionosphere tomography, GNSS reflectometry / scatterometry for altimetry, meteorology, soil moisture.
  • To exploit the potential of new signals’ structures (GPS-M, GALILEO, reactivated GLONASS) for GNSS based atmospheric remote sensing.
  • To suggest additional platforms for GNSS based atmospheric remote sensing (buoys, aircrafts, balloons, more dense ground networks, LEO constella-tions).
  • To follow, study and contribute towards the technical and scientific advances in atmospheric research.
  • To suggest standard definitions and terminology as per appropriate in the context of Geodesy and atmo-spheric sciences.
    Program of Activities
  • To promote research collaboration among research groups worldwide.
  • To organize and/or participate in scientific and professional meetings
  • To maintain a web page concatenating the Sub-Com-mission activities and reports.
  • To encourage special issues of the Journal of Geodesy on atmospheric applications to Geodesy.

Study Group

SG 4.3.1 Ionosphere Modelling and Analysis
Chair: Michael Schmidt (Germany)
Co-Chair: Mahmut O. Karslioglu (Turkey)

Terms of Reference

The general objective of this study group is the develop-ment of strategies for establishing ionosphere models which can be used for both, the correction of electro-magnetic measurements and the study of ionospheric features and their spatial-temporal evolution. Thus, our overall intention is the combination of physics, mathe-matics and statistics to derive a high-resolution multi-dimensional ionosphere model.

Working Groups

WG 4.3.1 Ionospheric Scintillation
Chair: Lucilla Alfonsi (Italy)

Terms of Reference

To coordinate the study of ionospheric scintillation by providing the scientific community with a statistical data-set about scintillation morphology, at high and low lati-tudes, as observed by means of GNSS satellites and encouraging discussions in dedicated forums, and to support current efforts taking place around the world to set up dedicated monitoring networks.

WG 4.3.2 GNSS-Based Sounding of the Atmosphere

Chair: Juha Luntama (Finland)

Terms of Reference

The objective of this Working Group is to explore and evaluate GNSS-based atmospheric sounding techniques establishing common international standards for model performance as well as investigate the potential contribu-tions of new GNSS signal structures to atmospheric studies.

WG 4.3.3 Numerical Weather Predictions for Positioning
Chair: Thomas Hobiger (Japan)

Terms of Reference

To study various technical aspects of using Numerical Weather Prediction (NWP) model data to map the effect of troposphere on space geodetic signals. To concatenate the terminology used by both meteorological and geo-detic communities. To test and sediment procedures related to ray-tracing through NWP data layers. To suggest quality control criteria to be used for assessing the quality of tropospheric data and results obtained from them. To evaluate state of the art and report the progress achieved during the time-life of the WG on the use of NWP for positioning.

SC 4.4 Applications of Satellite and Airborne Imaging Systems
President: Xiaoli Ding (Hong Kong)
Vice-President: Linlin Ge (Australia)
Secretary: Makoto Omura (Japan)

Terms of Reference

The main objectives of the Sub-Commission are to promote collaborative research in the development of satellite and airborne imaging systems, primarily includ-ing Synthetic Aperture Radar (SAR) and Light Detection And Ranging (LiDAR) systems, for geodetic applications, and to facilitate communications and exchange of data, information and research results through coordinated efforts.

  • Development of methods, models, algorithms and software for geodetic applications of satellite and air-borne imaging systems;
  • Study of effects of field and atmospheric conditions on satellite and airborne imaging systems;
  • Integration of satellite and airborne imaging systems with other geodetic/geospatial technologies such as GPS and GIS;
  • Development and promotion of new geodetic applica-tions of satellite and airborne imaging systems; and
  • Development of collaboration with sister organisations such as FIG and ISPRS, and liaison with image data providers.

Program of Activities
  • Produce a special issue on geodetic remote sensing in Journal of Geodesy;
  • Organise collaborative research activities among members of the Sub-Commission;
  • Sponsor and participate in various international con-ferences in geodetic remote sensing; and
  • Discuss collaborations with sister organisations.

Working Groups

WG 4.4.1 Quality Control Framework for InSAR Measurements
Chair: Xiaoli Ding (Hong Kong)

Terms of Reference

To study quality measures and quality control proce-dures and formulate a quality control framework for InSAR measurements.

WG 4.4.2: Imaging Systems for Monitoring Local Area Surface Deformation
Chair: Makoto Omura (Japan)

Terms of Reference

To study satellite and airborne imaging systems such as InSAR and LiDAR for monitoring local area ground sur-face deformations such as volcanic and seismic activi-ties, and ground subsidence associated with city development, mining activities, ground liquid withdrawal, and land reclamation.

SC 4.5 High-precision GNSS

President: Yang Gao (Canada)
Vice-President: Sunil Bisnath (Canada)
Secretary: Wu Chen (Hong Kong)

Terms of Reference

High-precision GPS has been applied to support numer-ous applications in the past decade. At least three other Global Navigation Satellite Systems (GNSS) are in dif-ferent phases of development and are expected to be full operational within the next five years. Novel technologies are needed to address the opportunities and challenges to enhance the accuracy, availability and integrity of high precision GNSS applications. SC4.5 will coordinate research efforts to identify important research problems in high-precision GNSS and develop methods and tech-nologies to support high-precision GNSS applications. The research subjects include optimal use of signals from multiple GNSS systems, improved error modelling and mitigation methodologies, quality control and integrity monitoring, differential GNSS RTK and precise point positioning, novel use of precise orbit/clock products and GNSS network infrastructures, cost-effective high-preci-sion GNSS applications. SC4.5 will also stimulate strong collaborations among international organizations and with the industry.


The major objective of SC4.5 is to promote collective research efforts on the development of high precision GNSS methods and technologies and their applications, to facilitate timely dissemination of scientific findings, and to stimulate strong collaborations among inter-national organizations and with the industry.

Program of Activities
  • Identify and investigate important technical issues and problems in high-precision GNSS
  • Promote research collaboration among researchers
  • Publish white papers
  • Collaborate with other international organizations
  • Develop linkage with the industry sector
  • Participate and organize international conferences and workshops

Working Groups

WG 4.5.1 Quality Measures for Network Based GNSS Positioning

Chair: Xiaolin Meng (UK)

Terms of Reference

To address quality control issues and develop quality measures for precise network-based RTK GNSS position-ing. Quality measures for emerging network based differ-ential GNSS positioning for a variety of location-based service applications will also be investigated.

WG 4.5.2 Precise Point Positioning and Applications

Chair: Sunil Bisnath (Canada)

Terms of Reference

To address and investigate issues and problems related to the development of GNSS-based precise point positioning technology and its integration with other positioning methods such as network RTK. The WG will promote novel applications of PPP.

WG 4.5.3 Correction Models for Ultrahigh-Precision GNSS Positioning

Chair: Wu Chen (Hong Kong)

Term of Reference

To promote research and development of precise correc-tion models such as atmospheric and geophysical correc-tions to further improve GNSS positioning accuracy and reliability.

WG 4.5.4 Multiple Carrier Ambiguity Resolution (MCAR)

Chair: Yanming Feng (Australia)

Terms of Reference

To study efficient approaches to carrier phase ambiguity resolutions with multiple GNSS signals from modernized GPS, GLONASS and Galileo systems and assess their benefits to GNSS technological advancements and appli-cations.

Study Groups

SG 4.2 GNSS Remote Sensing and Applications
President: Shuanggen Jin (South Korea)
Vice-President: James Garrison (USA)

Terms of Reference

Nowadays, the Global Positioning System (GPS), which is a very powerful and important contributor to all scientific questions related to high precision positioning on Earth’s surface, has been widely used as a mature technique in geodesy and geodynamics. Recently, the versatility and availability of reflected and refracted signals from GPS gave birth to many new GPS applications for various environmental remote-sensing in atmosphere, ocean and land. Many countries have initiated efforts in this area of researches and applications. The focus of this study group is to facilitate collaboration and communication, and to support joint researches with GNSS remote sensing.

A Steering Committee will work closely with members and other IAG Commissions/Sub-Commissions, specifically SC 4.3, to obtain mutual goals. Close collaboration with the International GPS Service (IGS), and IEEE Geoscience and Remote Sensing Society (IGARSS) will be promoted, such as joint sponsorship of international professional workshops and conferences.

  • To promote developments of current GPS reflected signal sensor and applications
  • To improve the existing estimation algorithms and data processing for GPS reflected signals.
  • To coordinate data collection campaigns and to com-pare with terrestrial and satellite observations, in order to encourage research and development into the crucial measurement and applications.
  • To investigate applications in atmosphere, ocean and land as well as space sciences.

  • Chair: Shuanggen Jin (Korea Astronomy and Space Science Institute, South Korea)
  • Co-chair: James L. Garrison (Purdue University, USA)
  • Vice-Chair: Attila Komjathy (JPL, NASA, USA)
  • Member-at-large: Isaac Ramos (Universitat Politecnica De Catalunya, Spain)

SG 4.3 IGS Products for Network RTK and Atmosphere Monitoring

President: Robert Weber (Austria)

Terms of Reference

The International GNSS Service (IGS) provides GPS & GLONASS station data and derived products like satellite orbits, clock corrections, electron content models and tropospheric delays of superior quality and within differ-ent time frames in support of Earth science research and multidisciplinary applications. Special applications like Network RTK in order to allow for fast access of a globally consistent reference frame for all position appli-cations and near/real-time atmospheric monitoring for weather prediction require GNSS products with greatly reduced delays. Soon these products will be made avail-able to the user community by means of the IGS RT Project in near-real time via Internet and other available streaming technologies.

This Study Group shall identify the needs of near real-time atmospheric monitoring in terms of orbit and clock-correction quality and investigate if the suite of IGS real-time products match the requested quality and spatial resolution necessary for correction data within regional RTK networks. Another topic deals with the coding of IGS products and models to be useful as a state space representation of error sources within the real-time stan-dard formats RTCM and RTCA.

This Study Group is directly linked to IAG Sub-Com-missions 4.3 and 4.5 as well as to the International GNSS Service (IGS).

  • To promote the use of IGS products for Network RTK and Atmosphere Monitoring
  • To identify the current needs of near real-time atmo-spheric monitoring and Network-RTK in terms of IGS product quality, delivery time and spatial resolution
  • To investigate options how to provide IGS products in standard real-time formats


This document has been provided by the Communicational and Outreach Branch of the International Association of Geodesy.