For the field surveyor to note his idea of the most

Info icon This preview shows pages 7–9. Sign up to view the full content.

View Full Document Right Arrow Icon
for the field surveyor to note his idea of the most logical route of leveling from the nearest located bench mark to the subject CGPS station. A location on the form was also provided to note the date that the field data was transmitted to the NGS via the NGS Online Recovery Program. A digital map file was prepared for each site showing the CGPS location as well as the NGS record location of the nearest five bench marks (see Appendix D for example). This allowed our field surveyors to drive directly to the area and to the best available record location of the bench marks using GPS navigation and moving map technology. In addition to the map, NGS data sheets were obtained via the NGS website for all of the known bench marks near the CGPS sites. These were furnished to the field surveyors in both printed and digital format for their use in locating, identifying, and verifying the existence and usability of the vertical control in the area. All necessary changes to the NGS records, along with the handheld GPS positions, which were derived from the reconnaissance operation, were transmitted to the NGS for incorporation into the National Geodetic Survey database via the NGS Online Recovery System. Field Leveling The following is the initial leveling instructions and procedures to field crews: Main Idea for Field Leveling: Version 1.10 (October 28, 2004) Page 7 of 36 6/14/2018 2:20 AM
Image of page 7

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

View Full Document Right Arrow Icon
At each CGPS site, level from the nearest NGS 1 st order NAVD88 benchmark to the antenna reference divot (ARD) (“punch mark”) on the CGPS “tripod” leg or base, following the Second Order, Class II CSRC Modified Specification (Appendix A). This specification details the process of a double run (closed loop) from the benchmark to the CGPS site with an additional single run to a second 1 st order benchmark for a check. Recommended Equipment: Leica NA 3003 Digital Level (with Version 3.3 firmware or higher) or equivalent Certified one piece bar code rods, with the stays (recommended) Stiff leg tripod Turning pucks Turning drive pins Steel rule, calibrated in meters and feet Field Procedures: 1. Calibration (collimation of level) to be accomplished once per day and the result entered into the level and used until the next calibration. 2. When using turning pucks for turn point, make sure personnel handling the rod are trained to step on the puck to assure that it is down as far as it will go and completely stable during the turn. Also make sure any drive pins set for turns are completely stable. 3. Maximum site length not to exceed 60 meters (Leica level specification) 4. Backsight/Foresight balance to be not more than 10 meters per setup and 10 meters accumulated per section. 5. Designate one rod as “A” Rod, use an even number of turns per section to make sure you take off the bench with “A” Rod and get back on the next bench with the same “A” Rod.
Image of page 8
Image of page 9
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