Last update: February 7, 2015

  •  Papers in refereed journals
  •  Papers in refereed conference proceedings
  •  Papers in non-refereed conference proceedings
  •  Other papers (presentations only)
  •  Chapters in honorary volumes
  •  Dissertations and published reports
  •  Technical Notes
  •  Seminar Notes
  •  Book reviews
  • Papers in refereed journals

    Kotsakis C., Vatalis A., Sanso F. (2014) On the importance of intra-frame and inter-frame covariances in frame transformation theory. Journal of Geodesy, vol. 88, no. 12, pp. 1187-1201. (full paper)

    Kotsakis C. (2013) Generalized inner constraints for geodetic network densification problems. Journal of Geodesy, vol. 87, no. 7, pp. 661-673. (full paper)

    Kotsakis C. (2012) A conventional approach for comparing vertical reference frames. Journal of Geodetic Science, vol. 2, no. 4, pp. 319-324. (full paper)

    Kotsakis C. (2012) Reference frame stability and nonlinear distortion in minimum-constrained network adjustment. Journal of Geodesy, vol. 86, no. 9, pp. 755-774. (full paper)

    Kotsakis C., Katsambalos K., Ampatzidis D. (2012) Estimation of the zero-height geopotential level in a local vertical datum from inversion of co-located GPS, leveling and geoid heights: a case study in the Hellenic islands. Journal of Geodesy, vol. 86, no. 6, pp. 423-439. (full paper)

    Kotsakis C. (2010) Heights and scale variation in their inherent reference frames. Bulletin of Geodesy and Geomatics, vol. LXIX, no. 1, pp. 23-34. (full paper)

    Kotsakis C., Katsambalos K. (2010) Quality analysis of global geopotential models at 1542 GPS/leveling benchmarks over the Hellenic mainland. Survey Review, vol. 42, no. 318, pp. 327-344. (full paper)

    Katsambalos K., Kotsakis C., Gianniou M. (2010) Hellenic terrestrial reference system 2007 (HTRS07): a regional realization of ETRS89 over Greece in support of HEPOS. Bulletin of Geodesy and Geomatics, vol. LXIX, no. 2-3, pp. 329-348. (full paper)

    Gianniou M., Katsambalos K., Kotsakis C. (2010) Real-time positioning in ETRS89 using the Hellenic Positioning System. Bulletin of Geodesy and Geomatics, vol. LXIX, no. 2-3, pp. 151-164. (full paper)

    Kotsakis C. (2009) A study on the reference frame consistency in recent Earth gravitational models. Journal of Geodesy, vol. 83, no. 1, pp. 31-50. (full paper)

    Kotsakis C., Katsambalos K., Gianniou M. (2009) Evaluation of EGM08 based on GPS and orthometric heights over the Hellenic mainland. Newton's Bulletin, Issue No. 4, pp. 144-163. (full paper)

    Kotsakis C. (2008) Scaling aspects in Helmert-type datum transformation for geoid heights. Bollettino di Geodesia e Scienze Affini, vol. LXVII, no. 1, pp. 1-18. (full paper)

    Kotsakis C. (2008) Transforming ellipsoidal heights and geoid undulations between different geodetic reference frames. Journal of Geodesy, vol. 82, no. 4/5, pp. 249-260. (full paper)

    Kotsakis C. (2007) A covariance-adaptive approach for regularized inversion in linear models. Geophysical Journal International, vol. 171, no. 2, pp. 509-522. (full paper)

    Kotsakis C. (2007) Least-squares collocation with covariance-matching constraints. Journal of Geodesy, vol. 81, no. 10, pp. 661-677. (full paper)

    Kotsakis C., Katsambalos K., Ampatzidis D. (2007) Extended similarity-type datum transformation for GPS heights and geoid undulations (in Greek). Technika Chronika - Scientific Journal of the Technical Chamber of Greece, vol. 27, no. 1/2, pp. 111-127. (full paper)

    Kotsakis C. (2006) Over-parameterized least-squares adjustment with linear models for geodetic and surveying applications. Journal of Surveying Engineering, vol. 132, no. 4, pp. 135-140. (full paper)

    Kotsakis C., Sideris M.G. (2006) Re-visiting least-squares: A discussion on the leading estimation principle in geodesy. Geodesy and Cartography, vol. 55, no. 1, pp. 3-22. (full paper)

    Kotsakis C. (2005) A type of biased estimators for linear models with uniformly biased data. Journal of Geodesy, vol. 79, no. 6/7, pp. 341-350. (full paper)

    Kotsakis C. (2005) On the trade-off between model expansion, model shrinking and parameter estimation accuracy in least-squares data analysis. Journal of Geodesy, vol. 79, no. 8, pp. 460-466. (full paper)

    Kotsakis C. (2005) Unbiasedness vs. unboundedness: an alternative perspective on the principle of least-squares estimation. Bollettino di Geodesia e Scienze Affini, vol. LXIV, no. 3, pp. 183-190. (full paper)

    Kotsakis C. (2005) Deterministic versus stochastic modelling of an unknown bias in linear Gauss-Markov models. Bollettino di Geodesia e Scienze Affini, vol. LXIV, no. 1, pp. 45-58. (full paper)

    Kotsakis C. (2004) The effect of an unknown data bias in least-squares adjustment: some concerns for the estimation of geodetic parameters. Newton's Bulletin, Issue No. 2, pp. 60-71. (full paper)

    Vella M.N.J.P., Kotsakis C. (2003) Similarity transformations for GPS heighting. GIS Development, vol. 7, no. 12, pp. 18-22. (full paper)

    Fotopoulos G., Kotsakis C., Sideris M.G. (2003) How accurately can we determine orthometric height differences from GPS and geoid data? Journal of Surveying Engineering, vol. 129, no. 1, pp. 1-10. (full paper)

    Kotsakis C., Sideris M.G. (2002) Non-stationary noise filtering of gravity data using fast spectral techniques. Bulletin of the International Geoid Service, Issue No. 13, pp. 35-50. (full paper)

    Bajracharya S., Kotsakis C., Sideris M.G. (2002) Aliasing effects in terrain correction computation using constant and lateral density variation. Bulletin of the International Geoid Service, Issue No. 12, pp. 38-47. (full paper)

    Fotopoulos G., Kotsakis C., Sideris M.G. (2002) Determination of the achievable accuracy of relative GPS/geoid levelling in northern Canada. Bulletin of the International Geoid Service, Issue No. 12, pp. 29-37. (full paper)

    Kotsakis C. (2001) Can we filter non-stationary noise from geodetic data with fast spectral (FFT) techniques? Bulletin of the International Geoid Service, Issue No. 11, pp. 93-114. (full paper)

    Kotsakis C., Sideris M.G. (2001) A modified Wiener-type filter for geodetic estimation problems with non-stationary noise. Journal of Geodesy, vol. 75, no. 12, pp. 647-660. (full paper)

    Fotopoulos G., Kotsakis C., Sideris M.G. (2000) A new Canadian geoid model in support of levelling by GPS. Geomatica, vol. 54, no. 1, pp. 53-62.

    Kotsakis C. (2000) The multiresolution character of collocation. Journal of Geodesy, vol. 74, no. 3/4, pp. 275-290. (full paper)

    Kotsakis C. (2000) The role of statistical collocation as a tool for constructing generalized multiresolution analyses in the L2(R) Hilbert space (invited contribution). Bollettino di Geodesia e Scienze Affini, vol. LIX, no. 2, pp. 125-160. (full paper)

    Kotsakis C., Sideris M.G. (1999) On the adjustment of combined GPS/leveling/geoid networks. Journal of Geodesy, vol. 73, no. 8, pp. 412-421. (full paper)

    Fotopoulos G., Kotsakis C., Sideris M.G. (1999) Development and evaluation of a new Canadian geoid model. Bolletino di Geofisica teorica ed applicata, vol. 40, no. 3/4, pp. 227-238. (full paper)

    Kotsakis C., Sideris M.G. (1999) Study of the gravity field spectrum in Canada in view of cm-geoid determination. Bolletino di Geofisica teorica ed applicata, vol. 40, no. 3/4, pp. 179-188. (full paper)

    Kotsakis C., Rossikopoulos D. (1999) Very accurate close-range triangulations: problems and alternatives (in Greek). Technika Chronika - Scientific Journal of the Technical Chamber of Greece, vol. 19, no. 3, pp. 11-23. (full paper)

    Papers in refereed conference proceedings

    Kotsakis C., Vatalis A., Sanso F. (2015) The Helmert transformation approach in network densification revisited. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 146, pp. ###-###. Proceedings of the IAG International Symposium on Reference Frames for Applications in Geosciences, Kirchberg, Luxemburg, October 13-17, 2014. (full paper)

    Chatzinikos M., Kotsakis C. (2015) Weighted vs. un-weighted MCs for the datum definition in regional networks. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 146, pp. ###-###. Proceedings of the IAG International Symposium on Reference Frames for Applications in Geosciences, Kirchberg, Luxemburg, October 13-17, 2014. (full paper)

    Kotsakis C. (2015) Reference station weighting and frame optimality in minimally constrained networks. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 142, pp. ###-###. Proceedings of the VIII Hotine-Marussi Symposium, Rome, Italy, June 17-21, 2013. (full paper)

    Kotsakis C., Tsalis I. (2014) Combination of geometric and orthometric heights in the presence of geoid and quasi-geoid models. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 141, pp. 235-239. Proceedings of the IAG International Symposium on Gravity, Geoid and Height Systems, Venice, Italy, October 9-12, 2012. (full paper)

    Grigoriadis V.N., Kotsakis C., Tziavos I.N., Vergos G.S. (2014) Estimation of the reference geopotential value for the local vertical datum of continental Greece using EGM08 and GPS/leveling data. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 141, pp. 249-255. Proceedings of the IAG International Symposium on Gravity, Geoid and Height Systems, Venice, Italy, October 9-12, 2012. (full paper)

    Vergos G.S., Grigoriadis V.N., Tziavos I.N., Kotsakis C. (2014) Evaluation of GOCE/GRACE global geopotential models over Greece with co-located GPS/leveling observations and local gravity data. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 141, pp. 85-92. Proceedings of the IAG International Symposium on Gravity, Geoid and Height Systems, Venice, Italy, October 9-12, 2012. (full paper)

    Kotsakis C. (2013) The role of a conventional transformation scheme for vertical reference frames. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 138, pp. 201-206. Proceedings of the IAG International Symposium on Reference Frames for Applications in Geosciences, Marne-La-Vallee, France, October 4-8, 2010. (full paper)

    Kotsakis C., Katsambalos K., Ampatzidis D., Gianniou M. (2010) Evaluation of EGM08 using GPS and levelling heights in Greece. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 135, pp. 481-488. Proceedings of the IAG International Symposium on Gravity, Geoid and Earth Observation, Chania, Greece, June 23-27, 2008. (full paper)

    Kotsakis C. (2009) Reference frame consistency in CHAMP and GRACE earth gravity models. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 133, pp. 371-378. Proceedings of the IUGG XXIV General Assembly, Perugia, Italy, July 2-13, 2007. (full paper)

    Kotsakis C. (2008) Correcting the smoothing effect of least-squares collocation with a covariance-adaptive optimal transformation. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 132, pp. 350-355. Proceedings of the VI Hotine-Marussi Symposium on Theoretical and Computational Geodesy, Wuhan, China, May 29 - June 2, 2006. (full paper)

    Kotsakis C. (2007) On the problem of geoid height transformation between different geodetic reference frames. Harita Dergisi, General Command of Mapping, Ankara, 73(18), pp. 136-141. Proceedings of the First International Symposium of the International Gravity Field Service, Istanbul, Turkey, August 28 - September 1, 2006. (full paper)

    Dermanis A., Kotsakis C. (2006) Estimating crustal deformation parameters from geodetic data: Review of existing methodologies, open problems and new challenges. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 131, pp. 7-18. Proceedings of the IAG International Symposium on Geodetic Deformation Monitoring: From Geophysical to Engineering Roles, Jaen, Spain, March 17-19, 2005. (full paper)

    Fotopoulos G., Kotsakis C., Sideris M.G. (2005) Estimation of variance components through a combined adjustment of GPS, geoid and levelling data. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 128, pp. 440-445. Proceedings of the IUGG XXIII General Assembly, Sapporo, Japan, June 30 - July 11, 2003. (full paper)

    Kotsakis C., Tziavos I.N. (2005) Parametric versus non-parametric methods for optimal weighted averaging of noisy data sets. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 128, pp. 434-439. Proceedings of the IUGG XXIII General Assembly, Sapporo, Japan, June 30 - July 11, 2003. (full paper)

    Kotsakis C., Fotopoulos G., Sideris M.G. (2002) A study on the effects of data accuracy and datum inconsistencies on relative GPS levelling. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 124, pp. 113-118. Proceedings of the IAG International Symposium on Vertical Reference Systems, Cartagena, Colombia, February 20-23, 2001. (full paper)

    Kotsakis C., Sideris M.G. (2002) Aliasing error modelling in single-input single-output linear estimation systems. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 123, pp. 43-48. Proceedings of the IAG International Symposium on Gravity, Geoid and Geodynamics, Banff, Canada, July 31 - August 4, 2000. (full paper)

    Kotsakis C., Sideris M.G. (2002) Non-stationary noise filtering of gravity data using fast spectral techniques. IGeS Bull. Special Issue, DIIAR Politechnico di Milano, no. 13, pp. 35-40. Proceedings of the EGU XXVI General Assembly (session G7: Regional and local gravity field approximation), Nice, France, April 26-30, 2001. (full paper)

    Kotsakis C., Sideris M.G. (2001) On the adjustment of combined GPS/Levelling/Geoid networks (extended abstract). IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 122, pp. 165-166. Proceedings of the IV Hotine-Marussi Symposium on Mathematical Geodesy, Trento, Italy, September 14-17, 1998.

    Kotsakis C. (2000) Wavelets and Collocation: an interesting similarity. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 121, pp. 214-220. Proceedings of the IUGG XXII General Assembly, Birmingham, U.K., July 18-30, 1999. (full paper)

    Fotopoulos G., Kotsakis C., Sideris M.G. (1999) Development and evaluation of a new Canadian geoid model. Proceedings of the Second Joint Meeting of the International Gravity Commission and the International Geoid Commission, pp. 227-238, Osservatorio Geofisico Sperimentale, Trieste, Italy, September 7-12, 1998.

    Kotsakis C., Sideris M.G. (1999) Study of the gravity field spectrum in Canada in view of cm-geoid determination. Proceedings of the Second Joint Meeting of the International Gravity Commission and the International Geoid Commission, pp. 179-188, Osservatorio Geofisico Sperimentale, Trieste, Italy, September 7-12, 1998. (full paper)

    Kotsakis C., Sideris M.G. (1998) Application of multiresolution filtering in geoid determination. IAG Symposia Series, Springer-Verlag Berlin Heidelberg, vol. 119, pp. 170-176. Proceedings of the IAG Scientific Assembly, Rio de Janeiro, Brazil, September 3-9, 1997.

    Papers in non-refereed conference proceedings

    Chatzinikos M., Kotsakis C. (2014) Quality assessment of the Hellenic Geodetic Reference System 1987 using a geodetic crustal velocity model for Greece (in Greek). e-Proceedings of the Fourth Scientific Conference of the Hellenic Association of Rural and Surveying Engineers, Thessaloniki, September 26-28, 2014. (full paper)

    Mikrou T., Ouzounoudis G., Kotsakis C. (2014) NETIST: A new software package for the adjustment and statistical analysis of geodetic and surveying networks (in Greek). e-Proceedings of the Fourth Scientific Conference of the Hellenic Association of Rural and Surveying Engineers, Thessaloniki, September 26-28, 2014. (full paper)

    Aslanidis N., Kotsakis C. (2014) Geo-referencing procedures for old land devision maps in the Hellenic Geodetic Reference System 1987 using GNSS observations: a case study in Dasochori, Serres (in Greek). e-Proceedings of the Fourth Scientific Conference of the Hellenic Association of Rural and Surveying Engineers, Thessaloniki, September 26-28, 2014. (full paper)

    Ampatzidis D., Kotsakis C., Katsambalos K. (2011) The need of a local reference frame in Greece: the deficiency of ETRS89 and a new proposed strategy. e-Proceedings of the Annual Symposium of the IAG Reference Frame Sub-Commission for Europe (EUREF2011), Chisinau, Moldavia, May 25-28, 2011. (full paper)

    Ampatzidis D., Kalamakis N., Katsambalos K., Kotsakis K. (2010) Alternative methods for transforming land division maps of the Hellenic Ministry of Agriculture to the official Hellenic Geodetic Reference System 1987 (in Greek). e-Proceedings of the Third Scientific Conference of the Hellenic Association of Rural and Surveying Engineers, Athens, December 17-18, 2010. (full paper)

    Kotsakis C. (2009) Heights and scale variation in their inherent reference frames. e-Proceedings of the Annual Symposium of the IAG Reference Frame Sub-Commission for Europe (EUREF2009), Florence, Italy, May 26-29, 2009.

    Katsambalos K., Kotsakis C., Gianniou M. (2009) Hellenic terrestrial reference system 2007 (HTRS07): a regional realization of ETRS89 over Greece in support of HEPOS. e-Proceedings of the Annual Symposium of the IAG Reference Frame Sub-Commission for Europe (EUREF2009), Florence, Italy, May 26-29, 2009.

    Gianniou M., Katsambalos K., Kotsakis C. (2009) Real-time positioning in ETRS89 using the Hellenic Positioning System. e-Proceedings of the Annual Symposium of the IAG Reference Frame Sub-Commission for Europe (EUREF2009), Florence, Italy, May 26-29, 2009.

    Kotsakis C., Ampatzidis D. (2007) Merging the geodetic networks of Greece and Egypt - An ambitious dream at the dawn of the 20th century (in Greek). Proceedings of the Scientific Conference on the Development and Evolution of the Surveying Instruments, Methods and Measurement Systems of the Mapping Sciences in Greece, Department of Rural and Surveying Engineering, AUTH, Thessaloniki, Greece, April 15-16, 2005, Editions Ziti, Thessaloniki, pp. 243-254. (full paper)

    Kotsakis C. (2007) The first aerial photogrammetric map of Athens (in Greek). Proceedings of the Scientific Conference on the Development and Evolution of the Surveying Instruments, Methods and Measurement Systems of the Mapping Sciences in Greece, Department of Rural and Surveying Engineering, AUTH, Thessaloniki, Greece, April 15-16, 2005, Editions Ziti, Thessaloniki, pp. 227-234. (full paper)

    Kotsakis C., Katsambalos K. (2006) On the need for developing a modern 3D satellite-based geodetic reference system in Greece: problems, alternatives and applications (in Greek). e-Proceedings of the Second Scientific Conference of the Hellenic Association of Rural and Surveying Engineers, Athens, December 8-9, 2006. (full paper)

    Kotsakis C. (2004) Challenging the logic of least-squares methods for geodetic estimation problems. Proceedings of the International Symposium on Modern Technologies, Education and Professional Practice in Geodesy and Related Fields, Sofia, Bulgaria, November 4-5, 2004, Bulgarian Academy of Sciences, pp. 38-45. (full paper)

    Kotsakis C. (2004) The effect of an unknown data bias on the statistical accuracy of least-squares solutions. e-Proceedings of the IAG International Symposium on Gravity, Geoid and Space Missions, Porto, Portugal, August 30 - September 3, 2004.

    Fotopoulos G., Kotsakis C., Sideris M.G. (2001) Determination of the achievable accuracy of relative GPS/geoid levelling in northern Canada. e-Proceedings of the IAG Scientific Assembly, Budapest, Hungary, September 2-7, 2001. (full paper)

    Bajracharya S., Kotsakis C., Sideris M.G. (2001) Aliasing effects in terrain correction computation using constant and lateral density variation. e-Proceedings of the IAG Scientific Assembly, Budapest, Hungary, September 2-7, 2001. (full paper)

    Bajracharya S., Kotsakis C., Sideris M.G. (2001) Geoid determination using different gravity reduction techniques. e-Proceedings of the IAG Scientific Assembly, Budapest, Hungary, September 2-7, 2001. (full paper)

    Kotsakis C., Sideris M.G. (2000) Aliasing error modelling in single-input single-output linear estimation systems. e-Proceedings of the IAG International Symposium on Gravity, Geoid and Geodynamics, Banff, Canada, July 31 - August 4, 2000. (full paper)

    Fotopoulos G., Kotsakis C. (2000) Correlation and spectral analysis of distance-dependent DGPS errors over a regional network. e-Proceedings of the IAG International Symposium on Gravity, Geoid and Geodynamics, Banff, Canada, July 31 - August 4, 2000. (full paper)

    Kotsakis C., Bayoud F.A., Sideris M.G. (2000) Wiener filter modifications for gravity field data using different resolution levels and non-atationary noise. e-Proceedings of the IAG International Symposium on Gravity, Geoid and Geodynamics, Banff, Canada, July 31 - August 4, 2000. (full paper)

    Other papers - Presentations Only

    Kotsakis C. (2014) Design, realization and operational aspects of a time-dependent high-accuracy geodetic reference frame for the Hellenic region (in Greek). Presented at the Fourth Scientific Conference of the Hellenic Association of Rural and Surveying Engineers, Thessaloniki, September 26-28, 2014.

    Kotsakis C. (2014) Solving the reference station weighting problem in minimally constrained networks. Presented at the Annual EUREF Symposium of the IAG Reference Frame Sub-Commission for Europe, Vilnius, Lithuania, June 4-6, 2014.

    Vatalis A., Kotsakis C., Sanso F. (2014) A rigorous approach for aligning regional GNSS networks to global reference frames based on the Helmert transformation. Presented at the Annual EUREF Symposium of the IAG Reference Frame Sub-Commission for Europe, Vilnius, Lithuania, June 4-6, 2014.

    Tsalis I., Amjadiparvar B., Kotsakis C., Sideris M.G. (2014) On the consistent combination of geometric and Helmert orthometric heights. Presented at the Annual Scientific Meeting of the Canadian Geophysical Union, Banff, Canada, May 4-8, 2014.

    Ampatzidis D., Kotsakis C., Katsambalos K. (2012) Realization of an optimal geodetic reference frame in the Hellenic area: open problems and proposals (in Greek). Presented at the Workshop on Tectonic Geodesy, Athens, January 25, 2012.

    Kotsakis C. (2010) Do we need a conventional transformation model for vertical reference frames? Presented at the Annual Symposium of the IAG Reference Frame Sub-Commission for Europe (EUREF2010), Gavle, Sweeden, June 2-5, 2010.

    Kotsakis C., Zoulida M., Terzopoulos D., Katsambalos K. (2010) Analysis of leveling heights over the Hellenic national geodetic network (in Greek). e-Proceedings of the Third Scientific Conference of the Hellenic Association of Rural and Surveying Engineers, Athens, December 17-18, 2010.

    Ampatzidis D., Kotsakis C., Katsambalos K., Rossikopoulos D. (2010) Comparison of a geodetically-derived velocity field from the permanent NOANET-GPS network (2007-2010) with a microplate tectonic motion model over Greece. Presented at the 15th WEGENER General Assembly, Istanbul, Turkey, September 14-17, 2010.

    Katsambalos K., Kotsakis C., Gianniou M. (2009) Hellenic Terrestrial Reference System 2007 (HTRS07): a regional realization of ETRS89 over Greece in support of HEPOS. Presented at the ILRS Technical Workshop on SLR Tracking of GNSS Constellations, Metsovo, Greece, September 14-19, 2009.

    Kotsakis C. (2009) HEPOS and coordinate transformations (in Greek). Presented at the Scientific Workshop on HEPOS, Hellenic Association of Rural and Surveying Engineers & Ktimatologio SA, Athens, Greece, February 24, 2009.

    Kotsakis C. (2009) Accuracy evaluation of the coordinate transformation model between HTRS07 and the official Hellenic Geodetic Reference System of 1987 (in Greek). Presented at the Scientific Workshop on HEPOS, Hellenic Association of Rural and Surveying Engineers & Ktimatologio SA, Athens, Greece, February 24, 2009.

    Kotsakis C., Katsambalos K. (2008) The official transformation model between the reference system of HEPOS and the national Hellenic Geodetic Reference System of 1987 (in Greek). Presented at the Scientific Symposium "HEPOS and modern geodetic reference systems: theory and practice, prospects and applications", Department of Rural and Surveying Engineering, AUTH, Thessaloniki, September 25-26, 2008.

    Katsambalos K., Kotsakis C. (2008) The geodetic reference system of HEPOS (in Greek). Presented at the Scientific Symposium "HEPOS and modern geodetic reference systems: theory and practice, prospects and applications", Department of Rural and Surveying Engineering, AUTH, Thessaloniki, September 25-26, 2008.

    Katsambalos K., Kotsakis C. (2008) Software modules for implementing the horizontal coordinate transformation between the reference system of HEPOS and the national Geodetic Reference System of 1987 (in Greek). Presented at the Scientific Symposium "HEPOS and modern geodetic reference systems: theory and practice, prospects and applications", Department of Rural and Surveying Engineering, AUTH, Thessaloniki, September 25-26, 2008.

    Kotsakis C., Katsambalos K., Ampatzidis D. (2008) GPS-based levelling: current status and future prospects (in Greek). Presented at the Scientific Symposium "HEPOS and modern geodetic reference systems: theory and practice, prospects and applications", Department of Rural and Surveying Engineering, AUTH, Thessaloniki, September 25-26, 2008.

    Katsambalos K., Kotsakis C., Vlachakis B., Ganilas A., Papoudas G. (2008) Time-dependent coordinate variations and velocity models (in Greek). Presented at the Scientific Symposium "HEPOS and modern geodetic reference systems: theory and practice, prospects and applications", Department of Rural and Surveying Engineering, AUTH, Thessaloniki, September 25-26, 2008.

    Kotsakis C. (2007) Coordinate transformation models between the Hellenic Geodetic Reference System of 1987 and the geocentric reference frames of ITRF/ETRF type (in Greek). Presented at the Scientific Workshop "HEPOS A new positioning service for Greece: Implementation, challenges and future prospects", School of Surveying Engineering, National Technical University of Athens (NTUA), Athens, Greece, December 6, 2007.

    Huang J., Kotsakis C., Gruber T. (2007) Review of evaluation methods and test results for the quality assessment of Earth gravity models after the CHAMP and GRACE satellite missions. Presented at the XXIV General Assembly of the International Union of Geodesy and Geophysics, Perugia, Italy, July 2-13, 2007.

    Malmquist C., Kotsakis C., Sideris M.G. (2004) An assessment of digital terrain models over Canada. Presented at the Joint Assembly of the American Geophysical Union and the Canadian Geophysical Union, Montreal, Canada, May 17-21, 2004.

    Kotsakis C. (2004) A critique on the logic of the least-squares principle for the estimation of geodetic parameters. Presented at the Joint Assembly of the American Geophysical Union and the Canadian Geophysical Union, Montreal, Canada, May 17-21, 2004.

    Kotsakis C., Malmquist C. (2004) An evaluation of various digital elevation models over Canada. Presented at the IAG International Symposium on Gravity, Geoid and Space Missions, Porto, Portugal, August 30 - September 3, 2004.

    Kotsakis C., Vella M.N.J.P. (2003) Improved fitting between gravimetric and GPS/levelling geoids using an extended similarity transformation model: a case study in Johor, Malaysia. Presented at the XXIII General Assembly of the International Union of Geodesy and Geophysics, Sapporo, Japan, June 30 - July 11, 2003.

    Fotopoulos G., Kotsakis C., Sideris M.G., El-Sheimy N. (2003) Development of a semi-automated approach for regional corrector surface modelling in GPS-levelling. Presented at the Annual Scientific Meeting of the Canadian Geophysical Union, Banff, Canada, May 10-14, 2003.

    Kotsakis C. (2003) Weighted averaging of multiple data sets with no a-priori statistical information: some examples for noise reduction with simulated gravity anomaly data of varying accuracy. Presented at the Annual Scientific Meeting of the Canadian Geophysical Union, Banff, Canada, May 10-14, 2003.

    Kotsakis C. (2002) Improving the agreement between gravimetric and GPS/levelling geoids with a non-rigid similarity transformation model. Presented at the Third Meeting of the International Gravity and Geoid Commission, Thessaloniki, Greece, August 26-30, 2002.

    Kotsakis C., Fotopoulos G., Sideris M.G. (2001) Optimal fitting of gravimetric geoid undulations to GPS/levelling data using an extended similarity transformation model. Presented at the Annual Scientific Meeting of the Canadian Geophysical Union, Ottawa, Canada, May 14-17, 2001.

    Kotsakis C. (2001) Multiresolution spectral filtering of spatially-varying noise from gravity field data. Presented at the Annual Scientific Meeting of the Canadian Geophysical Union, Ottawa, Canada, May 14-17, 2001.

    Fotopoulos G., Kotsakis C., Sideris M.G. (2001) A simulative analysis for the achievable accuracy of relative GPS/geoid levelling in western Canada. Presented at the Annual Conference of the GEOIDE Network of the Canadian Centres of Excellence, Fredericton, Canada, June 21-22, 2001.

    Kotsakis C., Sideris M.G. (2001) Spectral filtering of spatially varying noise from digital geo-data. Presented at the Annual Conference of the GEOIDE Network of the Canadian Centres of Excellence, Fredericton, Canada, June 21-22, 2001.

    Kotsakis C., Sideris M.G. (1999) The high-frequency structure of the gravity field in Canada. Presented at the Annual Scientific Meeting of the Canadian Geophysical Union, Banff, Canada, May 9-13, 1999.

    Kotsakis C., Sideris M.G. (1999) Optimal combination of ellipsoidal, orthometric and geoidal heights for levelling purposes. Presented at the Spring Meeting of the American Geophysical Union, Boston, Massachusetts, June 1-4, 1999.  (Invited)

    Chapters in dedicated honorary volumes

    Kotsakis C., Chatzinikos M. (2015) A comprehensive accuracy assessment of the Hellenic Geodetic Reference System 1987 from nationwide GPS observations. ... dedicated volume in honor of Prof. G. Paraschakis, Department of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Ziti Editions, Thessaloniki, pp. ##-##.

    Kotsakis C. (2015) Frame alignment of regional GNSS networks using the Helmert transformation: old and new perspectives. ... dedicated volume in honor of Prof. C. Kaltsikis, Department of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Ziti Editions, Thessaloniki, pp. ##-##.

    Kotsakis C., Chatzinikos M. (2015) Weighted versus unweighted minimum-constraints for the datum definition in regional GNSS networks. ... dedicated volume in honor of Prof. S. Yiannopoulos, Department of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Ziti Editions, Thessaloniki, pp. ##-##.

    Kotsakis C. (2013) Towards a conventional transformation model for vertical reference frames. On measurements of lands and constructions: dedicated volume in honor of Prof. D.G. Vlachos, Department of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Ziti Editions, Thessaloniki, pp. 319-330.

    Kotsakis C. (2013) Anatomy of minimum constraints in geodetic network adjustment. Thales: dedicated volume in honor of Prof. M. Contadakis, Department of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Ziti Editions, Thessaloniki, pp. 226-246.

    Kotsakis C. (2010) On the estimation of the reference geopotential value of local vertical datums. The apple of knowledge: dedicated volume in honor of Prof. D. Arabelos, Department of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Ziti Editions, Thessaloniki, pp. 151-167.

    Kotsakis C. (2009) Least-squares collocation and its smoothing effect. The terrestrial and stellar environment: dedicated volume in honor of Prof. G. Asteriadis, Department of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Ziti Editions, Thessaloniki, pp. 145-154.

    Kotsakis C. (2009) Some paradoxical results in least-squares data analysis (in Greek). Ydrogaia: dedicated volume in honor of Prof. C. Tzimopoulos, Department of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Ziti Editions, Thessaloniki, pp. 457-466.

    Dissertations and published technical reports

    Huang J., Kotsakis C. (eds., 2009) External Quality Evaluation Reports of EGM08. IAG/IGFS JWG Final Report, Joint Working Group "Evaluation of Global Earth Gravity Models" of the International Gravity Field Service and the International Association of Geodesy (Commission II). Published as a special issue in the joint bulletin of the Bureau Gravimetrique International and the International Geoid Service. (full volume)

    Kotsakis C. (2000) Multiresolution aspects of linear approximation methods in Hilbert spaces using gridded data. Ph.D Dissertation, UCGE Report Series, No. 20138, Department of Geomatics Engineering, University of Calgary, Canada.

    Kotsakis C., Sideris M.G. (1999) The long road from deterministic collocation to multiresolution approximation. Technical Report, No. 1999.5, Department of Geodesy and GeoInformatics, University of Stuttgart, Germany.

    Fotopoulos G., Kotsakis C., Sideris M.G. (1999) Evaluation of geoid models and their use in combined GPS/levelling/geoid height network adjustments. Technical Report, No. 1999.4, Department of Geodesy and GeoInformatics, University of Stuttgart, Germany.

    Kotsakis C. (1995) Close-range triangulations with very high accuracy and reliability requirements - The computer program SMANET for the adjustment of 3D close-range networks (in Greek). Dipl.Eng Thesis, Undergraduate Report Series, No. 173, Department of Rural and Surveying Engineering, Aristotle University of Thessaloniki, Greece.

    Research Reports

    Kotsakis C. (2013) A complete software package for the forward and inverse coordinate transformation between the old Hellenic Datum (Hatt 30'x30') and the Hellenic Geodetic Reference System 1987 (including alternative methodologies and additional modules) (in Greek). Technical report, National Hellenic Service of Cadastre and Mapping (OKXE), Athens.

    Kotsakis C., Katsambalos K., Gianniou M. (2008) Coordinate transformation model between the geodetic reference system of HEPOS (HTRS07) and the Hellenic Geodetic Reference System 1987: Basic methodology and numerical examples (in Greek). Technical notes, Department of Geodesy and Surveying (AUTH) and KTIMATOLOGIO SA.

    Katsambalos K., Kotsakis C. (2008) HTRS07: The geodetic reference system of HEPOS (in Greek). Final Research Contract Report, Hellenic Positioning System (HEPOS) Development Project, Operational Program: "Information Society", Department of Geodesy and Surveying, Aristotle University of Thessaloniki, Greece.

    Katsambalos K., Kotsakis C. (2008) Software modules for the implementation of the coordinate transformation model between HTRS07 and the Hellenic Geodetic Reference System 1987 (in Greek). Final Research Contract Report, Hellenic Positioning System (HEPOS) Development Project, Operational Program: "Information Society", Department of Geodesy and Surveying, Aristotle University of Thessaloniki, Greece.

    Kotsakis C., Katsambalos K. (2008) Development of the coordinate transformation model between HTRS07 and the Hellenic Geodetic Reference System 1987 (in Greek). Final Research Contract Report, Hellenic Positioning System (HEPOS) Development Project, Operational Program: "Information Society", Department of Geodesy and Surveying, Aristotle University of Thessaloniki, Greece.

    Kotsakis C., Katsambalos K., Gianniou M. (2008) Evaluation of EGM08 based on GPS and orthometric heights over the Hellenic mainland. Final Technical Report, Working Group on "Evaluation of Global Earth Gravity Models". Jointly coordinated by the International Association of Geodesy (IAG/Commission II, Gravity Field) and the International Gravity Field Service (IGFS).

    Kotsakis C., Katsambalos K., Gianniou M. (2007) Evaluation of PGM2007A using GPS and levelling heights in Greece. Interim Technical Report, Working Group on "Evaluation of Global Earth Gravity Models". Jointly coordinated by the International Association of Geodesy (IAG/Commission II, Gravity Field) and the International Gravity Field Service (IGFS).

    Technical Notes

    Kotsakis C. (2008) HEPOS, reference systems/frames and coordinate transformations (in Greek). Bulletin of the Hellenic Association of Rural and Surveying Engineers, Issue no. 191 (November-December), pp. 38-43.

    Vella M.N.J.P., Kotsakis C. (2003) Similarity transformations for GPS heighting. GIS Development, vol. 7, no. 12, pp. 18-22.

    Seminar Notes

    Kotsakis C. (2008) Coordinate transformation model between the Hellenic Geodetic Reference System 1987 and the reference system of HEPOS (in Greek). Technical Seminar Series organized by KTIMATOLOGIO S.A., Athens, December 3-5, 2008.

    Kotsakis C. (2008) The geodetic framework of HEPOS (in Greek). Technical Seminar Series organized by KTIMATOLOGIO S.A., Athens, December 3-5, 2008.

    Kotsakis C. (2007) Coordinate transformations in surveying engineering applications (in Greek). Technical Seminar Series organized by the Northern Greece Association of Rural and Surveying Engineers, Thessaloniki, December 17, 2007.

    Published Book Reviews

    Kotsakis C. (2003) Review of the book Foundations of Time-Frequency Analysis (author: Grochenig K.), 359 pp., 15 figs., Birkhauser, Boston, 2001, ISBN 0-8176-4022-3. In IAG Newsletter, Journal of Geodesy, 76(9-10): 588-589.

     
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