CORS

CORS Articles and Documents

CORS-OPUS Applications

Soler, T. and Wang, G. (2016). Interpreting OPUS-Static results accurately, J. Surv. Eng., published online March 29, 2016, 14 p.

Smith, D., G. Mader and G. Sella (2015). Recent activities at the National Geodetic Survey (Part 1 of 4), The American Surveyor, 12(1), 18, 20, 22-23.

Smith, D., K. Choi, D. Prouty, K. Jordan, and W. Herring (2014). Analysis of the TXDOT RTN and OPUS-RS from the Geoid Slope Validation Survey of 2011: Case Study of Texas, J. Surv. Eng., 140(4), 05014003, 12p.

Weston, N.D., and T. Soler (2013). OPUS use in Alaska: A favored positioning tool from the North Slope to the remote Aleutian Islands, Proc. ISCORD 2013: Planning for Sustainable Cold Regions, ASCE, 289-296.

Wang, G., and T. Soler (2013). Using OPUS for measuring vertical displacements in Houston, Texas, J. Surv. Eng., 139(3), 126-134.

Weston, N.D., and T. Soler (2012). Rigorous geodetic positioning in the Americas, Proc. 8th FIG Regional Conference, Montevideo, Uruguay, 26-29 November, 13 p.

Wang, G., and T. Soler (2012). OPUS for horizontal subcentimeter-accuracy landslide monitoring: Case sudy in Puerto Rico and Virgin Islands region, J. Surv. Eng., 138(3), 143-153.

Soler, T., J.-Y. Han, and N.D. Weston (2012). Alternative transformation from Cartesian to geodetic coordinates by least squares for GPS georeferencing applications, Computer & Geosciences, 42, 100-109.

Snay, R., K. Choi, G. Mader, C. Schwarz, T. Soler, and N. Weston (2011). How precise is OPUS? Part 3: The rest of the story, The American Surveyor, 8(7), 42, 44-46.

Snay, R., K. Choi, G. Mader, C. Schwarz, T. Soler, and N. Weston (2011). How precise is OPUS? Part 2: Available precision estimates, The American Surveyor, 8(6), 42, 44, 46.

Snay, R., K. Choi, G. Mader, C. Schwarz, T. Soler, and N. Weston (2011). How precise is OPUS? Part 1: Experimental results, The American Surveyor, 8(5), 49-50, 52, 53-54.

Soler, T. (Ed.) (2011). CORS and OPUS for Engineers. Tools for Surveying and Mapping Applications, American Society of Civil Engineers, Reston, VA, vi+186.

Soler, T., and D. Smith (2010). Rigorous estimation of local accuracies, J. Surv. Eng., 136(3), 120-125.

Weston, N.D., T. Soler, and G.L. Mader (2009). Rover station positional accuracies from OPUS as a function of reference station spacing and rover station occupation time. Proc. FIG Working Week, Eilat, Israel, 3-8 May 2009, 11 p.

Schwarz, C.R., R.A. Snay, and T. Soler (2009). Accuracy assessment of the National Geodetic Survey's OPUS-RS utility, GPS Solutions, 13(2), 119-132.

Snay, R.A., and T. Soler (2008). Continuously Operating Reference Station (CORS): History, applications, and future enhancements, J. Surv. Eng., 134(4), 95-104.

Schwarz, C.R. (2008). Heuristic weighting and data conditioning in the National Geodetic Survey Rapid Static GPS software, J. Surv. Eng., 134(3), 76-82

Weston, N.D., G.L. Mader, and T. Soler (2007). OPUS Projects - A Web-based application to administer and process multi-day GPS campaign data, Proc. FIG Working Week, Hong Kong, May 13-17, 10p.

Weston, N.D., T. Soler, and G.L. Mader (2007). Web-based solution for GPS data. NOAA OPUS, GIM International, 21(4), 23-25

Snay, R., M. Cline, W. Dillinger, R. Foote, S. Hilla, W. Kass, J. Ray, J. Rohde, G. Sella, and T. Soler (2007). Using global positioning system-derived crustal velocities to estimate rates of absolute sea level change from North American tide gauge records, J. Geophys. Res., 112(B04409), 1-11

Martin, D. (2007). Geodetic connections. OPUS Rapid Static, The American Surveyor, 4(3), 44, 46-48

Ray, J., D. Crump, & M. Chin (2007). New Global Positioning System reference station in Brazil, GPS Solutions, 11(1), 1-10

Stone, W (2006). The evolution of the National Geodetic Survey's Continuously Operating Reference Station network and Online Positioning User Service, Proc. 2006 ION-IEEE Position, Location, and Navigation Symp., April 25-27, San Diego, CA, 653-663

Soler, T., & A. Hernández-Navarro (2006). OPUS becomes available in Mexico, The American Surveyor, 3(9), 46-49

Schwarz, C.R. (2006). Statistics of range of a set of normally distributed numbers, J. Surv. Eng., 132(4), 155-159

Soler, T., N.D. Weston, R.A. Snay, G.L. Mader & R.H. Foote (2006). Precise georeferencing using the On-line Positioning User Service (OPUS), Proc. XXIII International FIG Congress, 8-13 October 2006, Munich, Germany, 12p.

Hernández-Navarro, A., & T. Soler (2006). Rigorous geodetic point positioning in Mexico, Proc. XXIII FIG Congress, Munich, Germany, Oct. 8-13, 8p.

Soler, T., P. Michalak, N.D. Weston, R.A. Snay & R.H. Foote (2006). Accuracy of OPUS solutions for 1- to 4-h observing sessions, GPS Solutions, 10(1), 45-55.

Ray, J., M. Morrison, S. Hilla, W. Dillinger & G. Mader (2005). Geodetic sensitivity to surface meteorological data: 24-hr and 6-hr observing sessions, GPS Solutions, 9(1), 12-20.

McGowan, Steve (2004). Ohio DOT's VRS Network, Professional Surveyor, 24(12), 8, 9,12, 14.

Hilla, S. & M. Cline (2004). Evaluating pseudorange multipath effects at stations in the National CORS network, GPS Solutions, 7(4), 253-267.

Mader, G.L., N.D. Weston, M.L. Morrison, & D.G. Milbert (2003). The On-line Positioning User Service (OPUS), Professional Surveyor, 23(5), 26, 28, 30.

Soler, T., R.A. Snay, R.H. Foote & M.W. Cline (2003). Maintaining accurate coordinates for the National CORS network, Proc. FIG Working Week, Paris, France, April 13-17, 8 p.

Snay, R., G. Adams, M. Chin, S. Frakes, T. Soler & N. Weston (2002). The synergistic CORS program continues to evolve, Proc. ION-GPS 2002, Portland, OR, September 24-27, 2630-2639.

Snay, R.A., T. Soler & M. Eckl (2002). GPS precision with carrier phase observations: Does distance and/or time matter?, Professional Surveyor, 22(10), 20, 22, 24.

Eckl, M.C., R. Snay, T. Soler, M.W. Cline & G.L. Mader (2001). Accuracy of GPS-derived relative positions as a function of interstation distance and observing-session duration, Journal of Geodesy, 75(12),633-640.

Gan, W., W.H. Prescott (2001). Crustal deformation rates in central and eastern U.S. inferred from GPS, Geophysical Research Letters, 28, 3733-3736.

Marshall, J., M. Schenewerk, R. Snay & S. Gutman (2001). The effect of the MAPS weather model on GPS-determined ellipsoidal heights, GPS Solutions, 5(1), 1-14.

Schenewerk, M.J., J. Marshall & W. Dillinger (2001). Vertical ocean-loading deformation derived from a global GPS network,J. Geodetic Soc. of Japan, 47(1).

Soler, T., R.E. Johnson, L.F. Thormahlen & R.H. Foote (2001). Combining two GPS techniques: Parting the waters, GPS World, 12(5), 28-30, 31.

Snay, R.A. (2000). The National and Cooperative CORS systems in 2000 and beyond, Proc. ION GPS-2000, Salt Lake City, UT, September 19-22, 55-58.

Soler, T., R.H. Foote, D. Hoyle & V. Bocean (2000). Accurate GPS orientation of a long baseline for neutrino oscillation experiments at Fermilab, Geophysical Research Letters, 27(23), 3921-3924.

Schenewerk, M.S., T.M. Vandam & R.S. Nerem (1999). Seasonal motion in the Annapolis, Maryland GPS monument. GPS Solutions, 2(3), 41-49.

Snay, R.A. & N.D. Weston (1999). Future directions of the National CORS system. Proc. 55^th Annual Meeting of the Institute of Navigation, Cambridge, MA, June 28-30, 301-305.

Soler, T., N.S. Doyle & L.W. Hall (1999). Rigorous transformation of GPS-determined vector components, Proc. ION GPS-99, Nashville, TN, September 14-17, 27-32.

Spofford, P.R. & N.D. Weston (1998). National Geodetic Survey Continuously Operating Reference Station project. Status and Plans. ACSM Bulletin, 172, 20-25.

Cheves, M. (1997). CORS update, Professional Surveyor, 17(2), 34-35.

Cheves, M. (1996a). No-cost GPS observations available nationally, Professional Surveyor, 16(2), 6, 8, 10.

Cheves, M. (1996b). CORS - A case study of a 1-man GPS crew, Professional Surveyor, 16(2), 10, 12, 13.

Strange, W.E. & N.D. Weston (1995). The establishment of a GPS Continuously Operating Reference Station system as a framework for the National Spatial Reference System. Proc. ION Nat. Tech. Meeting, Anaheim, CA, January 18-20, 19-24.

Strange, W.E.(1994). A national spatial data system framework continuously operating GPS reference stations. Proc. First Federal Geographic Technology Conference. GIS in Government, Washington D.C., September 26-28, 37-41.USA GIS World, Fort Collins, CO, USA.

Prusky, J. (2001). The Cooperative CORS Program, Professional Surveyor, 21(1), 14, 16, 22.

Antenna Calibrations

Bilich A., & G.L. Mader (2010). GNSS absolute antenna calibration at the National Geodetic Survey, Proc. ION 23rd International Technical Meeting, Portland, OR, Sept. 21-24, 1369-1377.

Mader, G.L. (1999). GPS antenna calibration at the National Geodetic Survey, GPS Solutions, 3(1), 50-58.

Tectonic Applications of CORS Data

Snay, R.A. & C. Pearson (2010). Coping with tectonic motion, The Am. Surv., 7(9), 28, 37-38, 40, 42.

Sella, G.F., S. Stein, T.H. Dixon, M. Craymer, T.S. James, S. Mazzotti & R.K. Dokka (2007). Observation of glacial isostatic adjustment in "stable" North America with GPS, Geophys. Res. Lett., 34(L02306), 1-6.

Dixon, T.H., F. Amelung, A. Ferretti, F. Novali, F. Rocca, R. Dokka, G. Sella, S.-W. Kim, S. Wdowinski & D. Whitman (2006). Subsidence and flooding in New Orleans. A subsidence map of the city offers insight into the failure of the levees during Hurricane Katrina, Nature, 441, 587-588. Supplementary information

Dokka, R.K, G.F. Sella & T.H. Dixon (2006). Tectonic control of subsidence and southward displacement of southeast Lousiana with respect to stable North America, Geophys. Res. Lett., 33(L23308), 1-5.

Coordinate Systems

A series of four papers about Terrestrial Reference Systems

Snay, R.A. & T. Soler (1999). Part 1 - Modern Terrestrial Reference Systems. Professional Surveyor, 19(10), 32-33.

Snay, R.A. & T. Soler (2000). Part 2 - The evolution of NAD83. Professional Surveyor, 20(2), 16, 18.

Snay, R.A. & T. Soler (2000). Part 3 - WGS 84 and ITRS. Professional Surveyor, 20(3), 24, 26, 28.

Snay, R.A. & T. Soler (2000). Part 4 - Practical considerations for accurate positioning. Professional Surveyor, 20(4), 32-34.

Reference Frames

Weston, N.D., & T. Soler (2014). Global Terrestrial Reference Systems and Frames in Reference Frames in Practice Manual, FIG Publication No. 64, G. Blick (Ed.), 15-18

Weston, N.D., T. Soler & D. Roman (2012). Recently adopted changes to the terrestrial reference frames used in the United States, Proc. FIG Working Week 2012, Rome, Italy, 6-10 May,14 p.

Collilieux, X., L. Métivier, Z. Altamimi, T. van Dam & J. Ray (2011). Quality assessment of GPS reprocessed terrestrial reference frame, GPS Solutions, 15(3), 219-231.

Ray, J., Z. Altamimi, X. Collilieux & T. van Dam (2008). Anomalous harmonics in the spectra of GPS position estimates, GPS Solutions, 12(1), 55-64.

Collilieux, X., Z. Altamimi, D. Coulot, J. Ray & P. Sillard (2007). Comparison of very long baseline interferometry, GPS, and satellite laser ranging height residuals from ITRF2005 using spectral and correlation methods, J. Geophys. Res., 112(B12403), 1-18.

Ray, J., J. Kouba & Z. Altamimi (2005). Is there utility in rigorous combination of VLBI and GPS EOPs?, Journal of Geodesy, 79(9), 505-511.

Ray, J. & Z. Altamimi (2005). Evaluation of co-location ties relating the VLBI and GPS reference frames, Journal of Geodesy, 79, 189-195.

Ray, J., D. Dong & Z. Altamimi (2004). IGS reference frames: status and future improvements, GPS Solutions, 8(4), 251-266.

Timing

Senior, K.L., Kouba, J., & Ray, J.R. (2010). Status and prospects for combined GPS load and VLBI UT1 measurements, Artificial Satellites, 45(2), 57-63.

Senior, K.L., Ray, J.R., & Beard, R.L. (2008). Characterization of periodic variations in the GPS satellite clocks, GPS Solutions, 12(3), 211-225.

Ray, J., & K. Senior (2005). Geodetic techniques for time and frequency comparisons using GPS phase and code measurements, Metrologia, 42(4), 215-232.

Orbits

Griffiths, J. & J.R. Ray (2009). On the precision and accuracy of IGS orbits, J. Geod., 83(3-4), 277-287.

Kass, W.G., R.L. Dulaney, J. Griffiths, S. Hilla, J. Ray & J. Rohde (2009). Global GPS data analysis at the National Geodetic Survey, J. Geod., 83(3-4), 289-295.

Transformations of Frames and Vectors

Soler, T., and J.-Y. Han (2016). On rotation of frames and physical vectors: an exercise based on plate tectonics theory, GPS Solutions., First online: 26 February 2016, pp 1-17

Soler, T., J.-Y. Han and N.D. Weston (2016). Variance-covariance matrix of transformed GPS positions: Case study for the NAD 83 geodetic datum, J. Surv. Eng., 142(1), 13 p. (04015004)

Soler, T., J-Y Han, and N.D. Weston (2014). On deflection of the vertical components and their transformations, J. Surv. Eng., 140(2), 04014005-1-15.

Snay, R. A., J. T. Freymueller, and C. Pearson (2013). Crustal motion models developed for version 3.2 of the Horizontal Time-Dependent Positioning Utility J. Appl. Geod., 7, 173-190.

Han, J-Y, T. Soler, J. Guo (2011). Utilizing non-iterative linear transformations between non-uniformly dilated 3D frames, Scientific Research and Essays, 6(31), 6435-6443.

Pearson, C., R. McCaffrey, J.L. Elliot, and R. Snay (2010). HTDP 3.0: Software for coping with the coordinate changes associated with crustal motion, J. Surv. Eng., 136(2), 80-90.

Han, J-Y, B.H.W. van Gelder, T. Soler, R.A. Snay (2007). Geometric combination of multiple terrestrial network solutions, J. Surv. Eng., 134(4), 126-131.

Soler, T. (2006). What is the relationship between the NAD 83 and WGS84 coordinates?GPS World Discussion Forums, 12-05-2006. Recent update, (2014). Transformations between WGS84 (G1674) and NAD 83 (2011) NGS Internal Document, 4p.

van Gelder, B.H.W. & Soler, T. (2005). Effects of errors in coordinates on transformation parameters [Discussion], J. Surv. Eng., ASCE, 131(4), 143-143.

Soler, T. & R.A. Snay (2004). Transforming positions and velocities between the International Terrestrial Reference Frame of 2000 and North American Datum of 1983, J. Surv. Eng., ASCE, 130(2), 49-55.

Snay, R.A. (2003). Horizontal Time-Dependent Positioning, Professional Surveyor, 23(11), 30, 32, 34.

Snay, R.A. (2003). Introducing two spatial reference frames for regions of the Pacific Ocean, Surveying and Land Information Science, 63(1), 5-12.

Soler, T. & J. Marshall. (2003). A note on frame transformations with applications to geodetic datums, GPS Solutions, 7(1), 23-32.

Soler, T. & J. Marshall. (2002). Rigorous transformation of variance-covariance matrices of GPS-derived coordinates and velocities, GPS Solutions, 6(1-2), 76-90.

Soler, T., N.D. Weston, & H. Han. (2002). Computing NAD 83 coordinates using ITRF-derived vector components, Proc. XXII FIG International Congress, ACSM/ASPR Annual Conference, April 19-26, Washington D.C., 6 pg.

Soler, T. (2001). Densifying 3D GPS networks by accurate transformation of vector components, GPS Solutions, 4(3), 27-33.

Soler, T. (2001). Transformaciones rigurosas de vectores GPS al marco de referencia SIRGAS, Revista Cartográfica, 72, 139-142. (in Spanish, English abstract)

Soler, T. (1999). Transformaciones rigurosas entre sistemas coordenados de referencia: Aplicación al GPS (ITRF, WGS84) y GLONASS (PZ-90), GeoConvergencia, 2(1), 30-38. (in Spanish and Portuguese)

Snay, R.A. (1998). Using HTDP software to transform spatial coordinates across time and between reference frames, Surveying and Land Information Systems, 59(1), 15-25.

Craymer, M., R. Ferland & R. Snay (1998). Realization and unification of NAD83 in Canada and the U.S. via the ITRF. In Proc. Int. Symp. IAG, Sect. II, "Towards an Integrated Geodetic Observing System (IGGOS), Munich, October 5-9, 5p.

Soler, T. (1998). A compendium of transformation formulas useful in GPS work, Journal of Geodesy, 72(7-8), 482-490.

Soler, T. (1991). Transforming deflections of the vertical between datums [in Spanish; English abstract], Revista Cartográfica, 60, 160-176.

Soler, T. & L.D. Hothem (1988). Coordinate systems used in geodesy: Basic definitions and concepts, J. Surv. Eng., ASCE, 114(2), 84-97.

Soler, T. & S.D. Johnson (1988). On stellar proper motion and its updating, Manuscripta Geodaetica., 13(1), 40-46.

Soler, T. & B.H.W. van Gelder (1987). On differential scale changes and the satellite Doppler system z-shift, Geophys. J.R. astr. Soc., 91, 639-656.

Soler, T. & S.D. Johnson (1987). Alternative geometric determination of altazimuthal-distance covariance matrices, J. Surv. Eng., 113(2), 57-69.

Soler, T. & M. Chin (1985). On transformation of covariance matrices between local Cartesian coordinate systems and commutative diagrams, Technical Papers. 45th Annual Meeting ACSM, Washington, D.C., March 10-15, 1985, 393-406.

Soler, T. (1985). A matrix representation of the potential second-rank gradient tensor for local modelling, Geophys. J. R. astr. Soc., 81(2), 363-379.

Soler, T. (1984). A new matrix development of the potential and attraction at exterior points as a function of the inertia tensors, Celestial Mechanics, 32(3), 257-296.

Soler, T. & I.I. Mueller (1980). Global plate tectonics and the secular motion of the pole, Nutation and the Earth's Rotation, IAU Symposium no. 78, 243-244.

Soler, T. & I.I. Mueller (1979). Global plate tectonics and the secular motion of the pole, Bull. Geod. 52(1), 39-57.

Soler, T. (1976). On differential transformations between Cartesian and curvilinear (geodetic) coordinates, Depart. of Geodetic Science, Report no. 236. The Ohio State University, Columbus, Ohio.

Other GPS Applications

Ray, J., J. Griffiths, X. Collileux, P. Rebischung (2013). Subseasonal GNSS positioning errors, Geophys. Res. Lett., 40(22), 5854-5860.

Collilieux, X., T. van Dam, J. Ray, D. Coulot, L. Métivier, Z. Altamimi (2012). Strategies to mitigate aliasing of loading signals while estimating GPS frame parameters, J. Geod., 86(1), 1-14.

Smith, D.A., E.A. Araujo-Pradere, C. Minter & T. Fuller-Rowell (2008). A comprehensive evaluation of the errors inherent in the use of a two-dimensional shell for modeling the ionosphere, Radio Sci., 43(RS6008), 1-23.

Scott, G. & P. Hensel (2007). Geodesy on the water's edge: Applications of accurate heights in the coastal zone, Hydro Int., 11(5), 16-18.

Hernández-Navarro, A. & T. Soler (2002). Glosario GPS y términos afines, Revista Cartográfica, 74-75, 148-226.

Soler, T. & R.J. Fury (2000). GPS alignment survey and meridian convergence, J. Surv. Eng., ASCE, 126(3), 69-82.

Soler, T., L.W. Hall & C.K. Reed (1998). Establishment of a high accuracy reference geodetic network in the Caribbean, Surv. and Land Inf. Systems, 58(1), 13-24.

Soler, T., G. Álvarez-García, A. Hernández-Navarro & R. Foote(1996). GPS high accuracy networks in Mexico, J. Surv. Eng, ASCE, 122(2), 80-94.

Soler, T., L.W. Hall (1995). Establishment of a high accuracy geodetic network in Romania, Surv. and Land Inf. Systems, 55(4), 183-191.

Soler, T., W.E. Strange, & L.D. Hothem (1992). Accurate determination of Cartesian coordinates at geodetic stations using the Global Positioning System, Geophys. Res. Lett., 19(6), 533-536.

Soler, T., J.D. Love, L.W. Hall & R.H. Foote (1992). GPS results from statewide high precision networks in the United States, Proc. Sixth Int. Geodetic Symp. on Satellite Positioning, The Ohio State University, 17-20 Sept., 573-582.

Soler, T., W.E. Strange & J.S. Ferguson (1991). Geodetic coordinate systems in Florida: GPS contribution, J. Surv. Eng., ASCE, 117(2), 77-96.

Soler, T., A.E. Carlson, Jr. & A.G. Evans (1989). Determination of vertical deflections using the Global Positioning System and geodetic leveling, Geophysical Research Letters, 16(7), 695-698.

Earth Rotation

Wu X., J. Ray, T. van Dam (2012). Geocenter motion and its geodetic and geophysical implications, J. Geodynamics, 58(1) 44-61.

Collilieux X., Z. Altamimi, J. Ray, T. van Dam, & X. Wu (2009). Effect of the satellite laser ranging network distribution of geocenter motion estimation, J. Geophys. Res., 114(B04402), 1-17.

Johnson, T.J., B.L. Luzum & J.R. Ray (2005). Improved near-term Earth rotation predictions using atmospheric angular momentum forecasts, J. Geodynamics, 39(3), 209-221.

Miscellaneous

Soler, T. (2014). William Bowie: Eminent Scientist. First Chairman (1926-1940) of ASCE's Surveying and Mapping Division, J. Surv. Eng., 140(1), 2-11.

Soler, T. (2013). Impact Factor Conundrum, J. Surv. Eng., 139(2), 69-71.

Soler, T., J.-Y. Han, and D. Smith (2012). Local accuracies, J. Surv. Eng., 138(2), 77-84.

Soler, T., and D. Smith (2012). "Closure to 'Rigorous estimation of local accuracies' by Tomás Soler and Dru Smith", J. Surv. Eng., 138(1), 48-50.

Soler, T. (2011). Book Review: Measure of the Earth: The Enlightenment expedition that reshaped our world by Larrie D. Ferreiro, J. Geod., 85(11), 882-884.

Soler, T. (2010). Advocating a renewed culture of surveying education, J. Surv. Eng., 136(3), 101.

Han, J.-Y., van Gelder, H.B.W. & Soler, T. (2007). On covariance propagation of eigenparameters of symmetric n-D tensors, Geophys. J. Int., 170, 503-510.

Soler, T. & M. Ruíz-Morales (2006). Letters from Carlos Ibáñez e Ibáñez de Ibero to Aimé Laussedat: new sources for the history of nineteenth century geodesy, J. Geod., 80, 313-321.

Soler, T. (1998). Book Review: The Problem of the Earth's Shape from Newton to Clairaut by John Leonard Greenberg, J. Geod., 72(3), 183-184.

Soler, T. (1997). A profile of General Carlos Ibáñez e Ibáñez de Ibero: first president of the International Geodetic Association, J. Geod., 71(3), 176-188.

Soler, T. (1997). Spain honors an illustrious geodesist: Jorge Juan y Santacilia (1713-1773), Prof. Surv., 17(6), 38, 40.

Soler, T. (1997). Arbitrary alterations, GPS World, 8(2), 12.

Soler, T., & D.W. Eisemann (1994). Determination of look angles to geostationary communication satellites, J. Surv. Eng. ASCE, 120(3), 115-127.

Soler, T., & B.H.W. van Gelder (1991). On covariances of eigenvalues and eigenvectors of second-rank symmetric tensors, Gophys. J. Int., 105(2), 537-546. See also Corrigendum