Using the Global Positioning System for Coastal Monitoring

Richard C. Daniels & Peter Ruggiero
Department of Ecology
Coastal Monitoring & Analysis Program
P.O. Box 47600
Olympia, WA 98504-7600

Slide Show!
  1. A word slide describing the basic methods used by the Global Positioning System (GPS) to calculate location based on known satellite locations.



  2. A word slide showing how distances are calculated between satellites and the receiver on the ground.



  3. A word slide showing how the derived GPS location for a point may be improved by the use of two or more receivers with one receiver located at a point with known X, Y, Z coordinates.



  4. Example of a new style National Geodetic Survey vertical control station (benchmark). This one is located in vegetated dunes near Astoria, OR.




  5. Example of an old style National Geodetic Survey horizontal control station. This one is located near the Pacific Ocean on a World War II observation bunker near Astoria, OR.



  6. A real time kinematic (RTK) GPS system with a 2-meter fixed height tripod with a L1/L2 GPS antenna with groundplain setup over a vertical control station. The large yellow box at the base of the 2-m tripod contains a Trimble 4000SI base receiver. The blue and white pole is the radio antenna that sends real time corrections to other roving GPS receivers. These corrections allow the roving receivers to correct their point location to within +/- 1 cm.

  7. A Trimble 4000SI receiver showing cable connections for the L1/L2 GPS antenna, battery, and external radio (blue cable).




  8. A Pacific Crest 35-watt radio connected to the base GPS receiver. This radio is used to send real-time radio corrections to the roving receivers.




  9. Radio repeater used to extend the range over which the roving receivers may travel by retransmitting the GPS corrections received from the base station 35-watt radio.




  10. Close up of a Pacific Crest Radio Repeater.






  11. A roving receiver taking a static point (control point). Note the L1/L2 GPS antenna on top of a 2-meter range pole and the black radio antenna attached to the backpack. This antenna allows the roving receiver to receive the GPS differential corrections broadcast by the base station radio.


  12. A roving receiver taking a ground control point at a feature that is visible on 1:12,000 air photography. This point (a World War II gun emplacement) will be used in the orthorectification process for the air photography.



  13. A roving receiver taking continues data as the operator walks a transect.





  14. A roving receiver mounted on a six-wheeled vehicle taking continues data. The vehicle is being used to obtain GPS data to derive a topographic map of the beach.




  15. A roving receiver mounted on a six-wheeled vehicle taking continues data. In this operation the GPS data is being stored into a laptop computer mounted inside the vehicle. This allows the operator to visually monitor the vehicles current and past location in real-time on the computers LCD screen.


  16. Vehicle operator navigating based on real-time position information displayed on a laptop computer mounted within the vehicle.




  17. Combined GPS and ecosounder system developed by Oregon State University. Note the L1/L2 GPS antenna mounted next the radio antenna. The ecosounder is mounted in the hull of the personal watercraft. The GPS data and depth data are combined to obtain detailed bathymetry data in the nearshore region, an area not reachable by conventional surveying methods.


  18. Launching the combined GPS and ecosounder system.





  19. Operation of the combined GPS and ecosounder system on the southwest Washington coast.




  20. Three-dimensional topographic surface derived from combined bathymetry and GPS data in Grayland, WA. Longshore direction is from right to left. Note the beach cusps that have been mapped near mean low water (yellow area). Colors indicate elevations in meters above NAVD88.



  21. The sun setting on the Pacific behind the full suite of RTK GPS equipment. Note that the GPS base station, 35-watt radio, and the GPS rover backpack are visible in this photo.

References

Kaminsky, G.M., P. Ruggiero, and G. Gelfenbaum. 1998. Monitoring coastal change in Southwest Washington and Northwest Oregon during the 1997/98 El Niño. Shore and Beach 66:42-51.

Kennedy, M. 1996. The Global Positioning System and GIS, An Introduction. Ann Arbor Press, Chelsea, MI.

Ruggiero, P., J. Côté, G. Kaminsky, and G. Gelfenbaum. 1999. Scales of variability along the Columbia River littoral cell. Coastal Sediments'99, ASCE, Long Island, NY.

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