Global Positioning System (GPS) surveyors on top of Capitol Building. L to R - David R. Doyle, NGS; unknown; Roy W. Anderson, NGS; Dennis Hoar, NGS. Front L to R -- Eric Desroche of Measurement Science Corp. and George Ott of Trimble Navigation. Observations made at the center of the Capitol Dome during maintenance and restoration of the Statue of Freedom

Looking SW from ground at scaffolding surrounding the top of the Capitol Building with the Statue of Freedom removed.

Statue of Freedom after restoration work and prior to being placed back atop the Capitol Building.

Staircase leading to the top of the Capitol Dome. The stairs get steeper the higher one goes. This was the route to the top of the Capitol for the GPS surveyors.

GPS antenna over Station Jefferson Pier. Looking south with the Jefferson Memorial in the background.

Inscription on Station Jefferson Pier

GPS antenna over Station Jefferson Pier with the Washington Monument in the background. Looking east.

Looking down on a brass plug marking the center of the Jefferson Pier. The grooves cut in the top of the stone monument run E/W and N/S.

GPS antenna over Station Jefferson Pier. Looking south with the Jefferson Memorial in the background.

View looking westerly up Pennsylvania Avenue from the top of the Capitol Building during GPS surveying operations. The Washington Monument is in the upper left corner of the image.

A GPS receiver sits astride the apex of the Washington Monument. Looking east towards the Capitol Building.

Mount used for placing GPS receivers on top of the Washington Monument. This mounting device was manufactured by the National Institute of Standards and Technology (NIST) in Gaithersburg, Maryland.

Looking north from the top of the Washington Monument during GPS surveying operations. The White House is in the center of the photo.

Atop the Washington Monument. Roy Anderson of the National Geodetic Survey is on left with David Ward of National Institute of Standards and Technology.

Looking down a 60-foot ladder from the top of the Washington Monument. All instruments and equipment had to be carried up and down this near vertical ladder during GPS operations. Not a good place for those with vertigo. Roy Anderson of NGS is on his way up.

View looking west from the top of the Washington Monument towards the Lincoln Memorial and the Reflecting Pool.

Mount used for placing GPS receivers on top of the Washington Monument. This mounting device was manufactured by the National Institute of Technology (NIST). David Ward of NIST is below and to right of mounting device.

Looking down and to the SE from the top of the Washington Monument. David Ward of NIST is to right of GPS receiver and mounting device that was made by NIST.

Roy Anderson of the National Geodetic Survey is setting up the mounting device manufactured by the National Institute of Standards and Technology for observing the top of the Washington Monument by GPS receivers.

View to the S from the top of the Washington Monument with the Jefferson Memorial in the center and Reagan National Airport in the background. Taken during GPS surveying operations on the Washington Monument.

Roy Anderson of the National Geodetic Survey monitoring a GPS receiver atop the Capitol Building.

A GPS receiver set up atop the U. S. Capitol Building. The receiver is occupying the location of the Statue of Freedom which had been removed for maintenance and restoration.

L to R - David Doyle, Roy Anderson, and Dennis Hoar are atop the Capitol Building during GPS surveying operations.

Looking west from the Capitol Building towards the Washington Monument during GPS surveying operations.

Looking up the paramedial of the Washington Monument. This is an interior vertical passage. Daniel Szwed of Alpha Corporation is up the ladder and opening a door to progress further up.

GPS receiver collecting data from above an elevator shaft in the interior of the Washington Monument.

The Hawaii Memorial Stone, one of many memorial stones placed in the Washington Monument.

Differential leveling with a Zeiss Digital Bar Code Level. David B. Crockett making observations and Joyce Turpin recording.

Leveling inside the Washington Monument. Edward Carlson holding the rod and Roy Anderson marking a place to hold the rod.

Leveling inside the Washington Monument. Edward E. Carlson is holding the rod and David B. Crockett is making observations with the leveling instrument.

Leveling operations on the Washington Monument grounds. Edward E. Carlson at left and David B. Crockett at the instrument.

Bench Mark A which is a monolite replica of the Washington Monument which is 12-feet tall and placed under a manhole cover on the south side of the Washington Monument grounds. Used during leveling operations.

The bench mark at Braddock's Rock. Used during leveling operations on the Washington Monument grounds.

The Jefferson Pier

The U. S. Meridian Stone which is located approximately in the center of the Ellipse south of the White House. The lines etched on the top are oriented N/S and E/W.

Roy W. Anderson, NGS, atop the Washington Monument

David R. Doyle, NGS, atop the Washington Monument

David B. Crockett, NGS, atop the Washington Monument

Ellis Veatch of Spectra Precision climbing 60-foot ladder for the final climb to the top of the Washington Monument

Roy W. Anderson, NGS, phoning the office from atop the Washington Monument.

Joseph G. Evjen, NGS, atop the Washington Monument

Looking straight down the west side of the scaffolding surrounding the Washington Monument from the 500-foot level.

Joseph G. Evjen, NGS, at Station Meridian Stone with scaffold shrouded Washington Monument in background.

Joseph G. Evjen, NGS, at Station Meridian Stone with the White House in the background.

Mike Nixon (L) and Ellis Veatch occupying the Zero Milestone of the Chesapeake and Ohio Canal with the Washington Monument in the background.

Looking west from atop the Washington Monument to the Reflecting Pool and the Lincoln Memorial. An airplane approaching Washington Reagan National Airport and Rosslyn, Virginia, are in the background.

Washington Monument with scaffolding still lit up in the dawn's early light.

View to the S from the top of the Washington Monument with the Jefferson Memorial in the center and Reagan National Airport in the background. Taken during GPS surveying operations on the Washington Monument.

Looking NNE. The Department of Commerce Building is in the foreground.

View looking ENE from the top of the Washington Monument. Smithsonian Museums are in the foreground and center while Capitol Building is in upper right.