ACE2: The New Global Digital Elevation Model

  • P. A. M. BerryEmail author
  • R. G. Smith
  • J. Benveniste
Conference paper
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 135)


Detailed accurate Digital Elevation Model (DEM) data have historically not been available on other than a regional scale, and often have uncertainties in both vertical and horizontal precision.

This paper presents the results of a global assessment of the unique Shuttle Radar Topographic Mission (SRTM) DEM using more than 100 million height datapoints derived from ERS1, ERS2, Topex, EnviSat and Jason-1 radar altimeter data, retracked using an expert system approach. This paper outlines the retracking approach taken to derive heights from the altimeter waveforms and describes the methodology for fusion of these data with the SRTM dataset, correcting errors in the SRTM heights and providing accurate measurements beyond the SRTM latitude limit, to produce a full global DEM.

Of particular interest, the unique ability of radar altimeters to provide very precise vertical measurements has allowed the correction of vertical offsets to better than 1 m within ACE2, and has also allowed identification of horizontal misplacements. As part of this development, a detailed quality matrix is being generated, to give users information both on the data source of each pixel, and an assessment of the vertical precision of the measurement. It is this detailed global assessment of quality that makes the ACE2 development both unique and of special value for a range of geodetic applications.

The first full release of ACE2 is scheduled for later in 2008.


Altimetry Digital elevation model (DEM) Shuttle radar topographic mission (SRTM) 



The authors wish to acknowledge ESA, NASA, JPL and CNES for supply of data used in this development.


  1. Algiers, J. (1993). TOPEX ground system software interface specification, (SIS-2) altimeter sensor data record (SDR) – Alt SDR data (NASA), March, 1993, JPL D-8591 (Rev. C), TOPEX 633-751-23-001, Rev. C.Google Scholar
  2. Benada, R. and S. Digby (1997). TOPEX/POSEIDON altimeter merged geophysical data record generation B (NASA/PO.DAAC), JPL PO.DAAC 068.D002. Jet Propulsion Laboratory, Pasadena, CA.Google Scholar
  3. Benveniste, J., S. Baker, O. Bombaci, C. Zeli, P. Venditti, O.Z. Zanife, B. Soussi, J.P. Dumont, J.P. Stum, and M. Milagro-Perez (2002). ENVISAT RA-2/MWR product handbook, Issue 1.2, PO-TN-ESR-RA-0050. European Space Agency, Frascati, Italy.Google Scholar
  4. Berry, P.A.M. (2000). Topography from land radar altimeter data: possibilities and restrictions. Phys. Chem. Earth(A), 25(1), 81–88.CrossRefGoogle Scholar
  5. Berry, P.A.M., J.E. Hoogerboord, and R.A. Pinnock (2000). Identification of common error signatures in global digital elevation models based on satellite altimeter reference data. Phys. Chem. Earth(A), 25(1), 95–99.CrossRefGoogle Scholar
  6. Berry, P.A.M., J.D. Garlick, and R.G. Smith (2007). Near-global validation of the SRTM DEM using satellite radar altimetry. Remote Sens. Environ., 106(1), 17–27, DOI: 10.1016/j.rse.2006.07.011.CrossRefGoogle Scholar
  7. Brown, C.G., Jr., K. Sarabandi, and L.E. Pierce (2005). “Validation of the shuttle radar topography mission height data,” geoscience and remote sensing. IEEE Trans., 43(8), 1707–1715, August 2005.Google Scholar
  8. CA. Capp, P. (2001). Altimeter waveform product ALT.WAP compact user guide, Issue 4.0, PF-UG-NRL AL-0001, Infoterra Ltd., UK.Google Scholar
  9. Denker, S. (2004). Evaluation of SRTM3 and GTOPO30 terrain data in Germany. In: Jekeli C. et al. (eds), International association of geodesy symposia, gravity, geoid and space missions, Vol 129. Springer Verlag, Berlin, pp. 218–223.Google Scholar
  10. Hall, O., G. Falorni, and R.L. Bras (2005). Characterization and quantification of data voids in the shuttle Radar topography mission data. Geosci. Remote Sens. Lett. IEEE, 2(2), 177–181, April 2005.CrossRefGoogle Scholar
  11. Hensley, S., P. Rosen, and E. Gurrola (2000). “The SRTM topographic mapping processor,” Geoscience and Remote Sensing Symposium, 2000. Proceedings. IGARSS 2000. IEEE 2000 Int., 3, 1168–1170.Google Scholar
  12. Hilton, R.D., W.E. Featherstone, P.A.M. Berry, C.P.D. Johnson, and J.F. Kirby (2003). Comparison of digital elevation models over Australia and external validation using ERS-1 satellite radar altimetry. Aust. J. Earth Sci., 50(2), 157–168(12), April 2003, DOI:10.1046/j.1440-0952.2003.00982.x.CrossRefGoogle Scholar
  13. Kellndorfer, J.M., W.S. Walker, L.E. Pierce, M.C. Dobson, J.A. Fites, C. Hunsaker, et al. (2004). Vegetation height estimation from shuttle radar topography mission and national elevation datasets. Remote Sens. Environ., 93, 339–358.CrossRefGoogle Scholar
  14. Lemoine, F.G., D.E. Smith, L. Kunz, R. Smith, E.C. Pavlis, N.K. Pavlis, S.M. Klosko, D.S. Chinn, M.H. Torrence, R.G. Williamson, C.M. Cox, K.E. Rachlin, Y.M. Wang, S.C. Kenyon, R. Salmon, R. Trimmer, R.H. Rapp, and R.S. Nerem (1997). The development of the NASA GSFC and NIMA joint geopotential model. In: Segawa, J. et al. (eds), International association of geodest symposia, gravity, geoid and marine geodesy, vol 117. Springer Verlag, Berlin, pp. 461–469.Google Scholar
  15. Scharroo, R. and P.N.A.M. Visser (1998), Precise orbit determination and 459 gravity field improvement for the ERS satellites. J.. Geophys. Res., 103(C4), 8113–8127.CrossRefGoogle Scholar
  16. Smith, B. and D. Sandwell (2003). Accuracy and resolution of Shuttle Radar 462 topography mission data. Geophys. Res. Lett., 30(9), 1467.CrossRefGoogle Scholar
  17. Zanife, O.Z., J.P. Dumont, J. Stum, and T. Guinle (2004), SSALTO Products Specifications – Volume 1: Jason-1 User Products, Issue 3.1, SMM-ST-M-EA-10879-CN, CLS/CNES. Toulouse, France.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2010

Authors and Affiliations

  1. 1.E.A.P.R.S. LabDe Montfort UniversityLeicesterUK
  2. 2.Earth and Planetary Remote Sensing LaboratoryDe Monfort UniversityLeicesterUK
  3. 3.Applications and Future Technologies DptEuropean Space Agency, Earth Observation ScienceFrascatiItaly

Personalised recommendations