GNSS for Hazard Monitoring

Summary of Activities

The research in this area focuses on the further development and applications of GNSS (Global Navigation Satellite Systems), especially the GPS (Global Positioning System) for the study of:

  • Deformation and dynamic behaviours of structures such as tall buildings, bridges and dams under various loading conditions;
  • The development of landslides;
  • Tectonic plate motion and crustal deformations; and
  • The variations of the state of the atmosphere for weather forecasting and related research.

The research group collaborates closely with other international research centres and the industry.

 

The technological services that we provide include:

  • Study and reduce the effects of various GNSS errors in precise deformation monitoring including especially the GNSS multipath effects and tropospheric delays;
  • Develop innovative solutions to problems encountered in GNSS deformation monitoring, such as the multi-antenna GNSS systems;
  • Develop new and more effective GNSS data processing methods and software systems;
  • Study with GNSS technologies ground and structural deformations and atmospheric conditions.

Representative Projects

  • Development of super-high accuracy GPS technology for structural deformation monitoring
  • Development of integrated GPS and accelerometer systems for structural deformation monitoring
  • High precision automatic measurement of natural and cut slope deformations to prevent disasters
  • Study of sea level change and vertical ground motion in Hong Kong
  • Estimation of real-time precipitable water vapor (PWV) in the Hong Kong region based on GPS measurements
  • Monitoring and modelling local ionosphere using regional GPS networks

 

Patented multi-antenna GPS system for structural and landslide monitoring

 

 

 

 

 

 

 

 

 

 

 

 

A highway slope monitored with a multi-antenna GPS system

 

A slope in Hong Kong and the motion of a point on the slope monitored with GPS

The Di-Wang tower in Shenzhen, China, monitored with GPS (the arrow shows the position of a GPS receiver)

Vibration of the Di-Wang tower in the North-South direction measured with GPS

 

Horizontal velocities of the GPS stations and their uncertainties at 95% confidence level relative to the Hong Kong fiducial network

Major Facilities

  • Over 10 geodetic quality GPS receivers
  • Various GPS data processing software packages

Selected Research Output

1.         Chan, W.S., Xu, Y.L., Ding, X.L., Xiong, Y.L., Dai, W.J. (2006) “Assessment of dynamic measurement accuracy of GPS in three dimensions”, Journal of Surveying Engineering, 132 (3): 108-117.

2.         Chan, W.S., Xu, Y.L., Ding, X.L. and Dai, W.J. (2006) “An integrated GPS-accelerometer data processing technique for structural deformation monitoring”, Journal of Geodesy, 80(12): 705-719.

3.         Chen, W., Hu, C.W., Chen, Y.Q., Ding, X.L. and Kwok, C.W. (2003) “GPS rapid static and kinematic positioning based on GPS active network”, Geo-Spatial Information Science, 6(1): 5-11.

4.         Chen, W. Chen, Y.Q. and Ding, X.L. (2006) “GNSS Applications in Deformation Monitoring, Intelligent Transport Systems, Precise Point Positioning and Atmosphere Study”, GIS Development Asia Pacific, 10(6): 38-43.

5.         Chen, W., Gao, G., Hu, C.W., Chen, Y.Q. and Ding, X.L. (2008) “Effects of ionospheric disturbances on GPS observation in low latitude area”, GPS Solutions, 12:33-41.

6.         Chen, W. Hu, C. Li, Z. Chen, Y.Q. Ding, X. L. Gao, S. and Ji, S. (2004) “Kinematic GPS Precise Point Positioning for Sea Level Monitoring with GPS Buoy”, Journal of Global Positioning Systems, 3(1-2): 302-307.

7.         Chen, Y.Q., Ding, X.L. and Shi, W.Z. (2004) “Hazards Monitoring and Mitigation with GPS and GIS: A Review”, Journal of Geospatial Engineering, 6(2): 1-9.

8.         Dai, W.J., Ding, X.L., Li, Z.W., Kwok, K.C.S. and Campbell, S. (2006) “Tropospheric Effects on GPS Measurements in Monitoring Tall Buildings”, Location, 5(1): 36-39.

9.         Ding, X.L., Huang, D.F., Yin, J.H., Chen, Y.Q., Lau, C.K., Yang, Y.W. and Sun, Y.R. (2003) “A new generation of multi-antenna GPS system”, Bulletin of Surveying and Mapping, 321: 13-15.

10.     Ding, X.L., Huang, D.F., Yin, J.H., Chen, Y.Q., Lau, C.K., Yang, Y.W., Sun, Y.R., Chen, W., He, X.F. (2003) Development and Field Testing of a Multi-Antenna GPS System for Deformation Monitoring, Wuhan University Journal of Natural Sciences, Vol. 8, No. 2B, pp. 671-676.

11.     Ding, X.L., Zheng, D., Dong, D.N., Ma, C., Chen, Y.Q. and Wang, G.L. (2005) “Seasonal and secular positional variations at collocated GPS and VLBI stations”, Journal of Geodesy, 79:71-81.

12.     Fan, K.K. and Ding, X.L. (2006) “Estimation of GPS carrier phase multipath signals based on site environment”, Journal of Global Positioning Systems, 5(1-2): 22-28.

13.     He, X.F., Sang, W.G., Chen, Y.Q. and Ding, X.L. (2005) “Steep-slope monitoring: GPS multiple-antenna system at Xiaowan dam”, GPS World, November, pp. 20-25.

14.     He, X.F., Yang, G., Ding, X.L. and Chen, Y.Q. (2004) “Application and Evaluation of a GPS Multi-Antenna System for Dam Deformation Monitoring”, Earth Planets Space, 56(11): 1035-1039.

15.     Ji, S.Y., Chen, C., Zhao, C.M., Ding, X.L. and Chen, Y.Q. (2007) “Single epoch ambiguity resolution for Galileo with the CAR and LAMBDA methods”, GPS Solutions, 11:259-268.

16.     Li, Z.W., Ding, X.L., Liu, G.X. and Huang, C. (2003) “Atmospheric Effects on InSAR Measurements - A Review”, Geomatics Research Australasia, 79: 43-58.

17.     Sun, Y.R., Ding, X.L., Chen, W. and Liu, J.Y. (2003) “Data Acquisition and Control of a Multi-Antenna GPS”, Data Acquisition and Processing, 18(1): 74-77.

18.     Xiong, Y.L., Ding, X.L., Huang, D.F., Dai, W.J. and Chan, W.S. (2005) “Integrated Single Epoch Algorithm Based on Wavelet Transform and Its Application to Structural Vibration Monitoring”, ACTA Geodaetica et Cartographica Sinic, 34(3): 202-207.

19.     Xiong, Y.L. and Ding, X.L. (2005) “Mitigation of GPS diffraction effects for deformation monitoring applications based on environment modeling”, ACTA Geodaetica et Cartographica Sinica.

20.     Yin, J.H., Ding, X.L. and Yang, Y.W. (2003) “Application of GPS and Traditional Methods to Remotely Monitor Landslides”, Chinese Journal of Disaster Prevention and Mitigation Engineering, 23(2): 14-21.

21.     Yuan, L.G., Huang, D.F., Ding, X.L., Xiong, Y.L., Zhong, P. and Li, C.G. (2004) “On the influence of signal multipath effects in GPS carrier phase surveying”, Acta Geodaetica et Cartographica Sinica, 33(3): 210-215.

22.     Zhong, P., Ding, X.L., Zheng, D.W., Chen, W. and Huang, D.F. (2008) “Adaptive wavelet transform based on cross-validation method and its application to GPS multipath mitigation”, GPS Solutions, 12:109-117.

23.     Zhong, P., Ding, X.L., Zheng, D., Chen, W., Huang, D.F. (2007) “An adaptive wavelet transformation based on cross-validation and its application to mitigate GPS multipath effects”, ACTA Geodaetica et Cartographica Sinica, 36(3): 279-285.

24.     Zhong, P., Ding, X.L., Zheng, D., Chen, W. and Xu, Y.L. (2007) “Filtered based GPS structural vibration monitoring methods and comparison of their performances”, ACTA Geodaetica et Cartographica Sinica, 36(1): 31-36.

25.     Zhong, P., Ding, X.L. and Zheng, D.W. (2005) “Study of GPS Multipath Effects with Method of CVVF”, ACTA Geodaetica et Cartographica Sinica, 34(2): 161-167.

Contact Information of the Contact Person

Prof. Xiao-Li Ding
Department of Land Surveying and Geo-Informatics
The Hong Kong Polytechnic University
Telephone: +852 2766 5965
Fax: +852 2330 2994
Email: lsxlding@polyu.edu.hk

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Research Centre for Urban Hazards Mitigation