When completed in the late 1990s, the Los Angeles Metro Rail project will provide a high speed transportation system servicing the metropolitan area. The Southern California Rapid Transit District, the governing authority for this major project, used Global Positioning Satellite (GPS) for control surveying in the early stages of the project's development. GPS surveys taken in a differential mode provide relative accuracies of 5 to 10 parts per million without the need for intervisibility of points and over distances either too long or too short for conventional surveying methods. Traffic congestion, diverse terrain, and limited visibility between points challenged the required accuracy and short time schedule for the project. GPS observations were begun on July 25, 1988. Six days were required to complete the GPS observations on 61 survey stations. Each day's observations were processed in a batch mode at night. A final step in the data processing was to combine all the base lines into a three-dimensional least squares network adjustment. The entire GPS survey for the MOS 2 line of the Metro Rail was completed in three weeks, which is three to four times faster than conventional surveying methods. A 30% cost savings was realized.

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  • Corporate Authors:

    Public Works Journal Corporation

    P.O. Box 688
    Ridgewood, NJ  United States  07451
  • Publication Date: 1989-6

Media Info

  • Features: Photos;
  • Pagination: p. 87-88
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00485292
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Jul 31 1989 12:00AM