Each cgps has a reference mark or divot ard on one of

Info icon This preview shows pages 6–8. Sign up to view the full content.

View Full Document Right Arrow Icon
Each CGPS has a reference mark or divot (ARD) on one of the tripod legs. This mark was created as part of the original installation contract of the Wyatt drilled-braced monument installations (CSRC, 2003). (A similar mark was created on the other types of monument installations for use in this leveling project.) The leveling project would establish an elevation on each of these ARD using the electronic leveling equipment. From this ARD mark, a manual measurement (using a steel rule) would be made up to the bottom of the antenna adaptor, which can be accessed from the underside of the tripod/antenna connection. Then the radome would be removed which allows access to measure from the bottom of the adaptor to the top of the adaptor. This measurement was to be done in each of the cardinal directions, in both meters and feet (for a check), and then averaged to determine the adaptor height. These measurements allow for calculation of the GRM and BPA elevations, based on the machining specifications of the adaptors (SCIGN, 1999), and are able to be completed in a few minutes for minimized disruption of the GPS data. The following general formulas are used to determine the elevations: Leveled ARD elevation + distance to bottom adaptor + adaptor height = BPA elevation BPA calculated elevation – 0.0083 meters = GRM elevation (with SCIGN adaptor) The time of removal and replacement of the radome was to be recorded for use by SOPAC/SCIGN to track any anomalies in the data. Version 1.10 (October 28, 2004) Page 6 of 36 6/14/2018 2:20 AM Figure No. 2. Typical SCIGN antenna.
Image of page 6

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Field Project Mobilization (after issuance of contract) Once the final sites were determined, site contact personnel were notified of the pending survey. This proved to be more of an issue than initially expected due to the fact that many of the on-site contacts listed in the SCIGN database had retired or moved on since last contacted by any of the CGPS network personnel. Field note forms to be used in the reconnaissance phase were prepared. Two different forms were prepared. The first form was designed for use in recording the site condition and the measurements necessary to determine the height difference from the antenna reference divot (ARD), which is generally a punch mark on the leg of the CGPS tripod. Additionally, this form was used to record the surveyor, date, the time of removal and reinstallation of the radome, the antenna make and the antenna serial number (see Appendix B for example). The second reconnaissance form was designed to record the condition of the found benchmark monuments (see Appendix C for example). These note sheets had blanks for recording the NGS permanent identification numbers (PID) of the marks and the stampings of the marks. The form provided blanks for latitude and longitude of the mark as determined by handheld GPS, suitability for use of the mark by GPS, and space for any notes thought necessary by the field surveyor to show changes from the NGS records, or any other data that might be pertinent to the project. Additionally, space was provided
Image of page 7
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern