<?xml version="1.0" ?><rss version="2.0"><channel><title><![CDATA[National Radio Astronomy Observatory GPS Marker]]></title><link><![CDATA[http://explorer.altopix.com/map/q2vyaa/National_Radio_Astronomy_Observatory_GPS_Marker.htm#comments]]></link><description><![CDATA[NASA ID: North Liberty-VLBA GPS STATION MARK-JPL 4007-S 1992]]></description><language>en-us</language><pubDate>2007-08-09T21:58:01-4294967289:00</pubDate><lastBuildDate>2008-12-02T14:43:47-4294967289:00</lastBuildDate><generator>Altopix RSS generator</generator><webMaster>explorer@altopix.com</webMaster><item><title><![CDATA[krešimri Ljulj]]></title><link><![CDATA[http://explorer.altopix.com/map/q2vyaa/National_Radio_Astronomy_Observatory_GPS_Marker.htm#comments]]></link><author><![CDATA[explorer@altopix.com]]></author><description><![CDATA[this is central station for GPS, which contol GPS constalation by using pseudodistances from another 5 control station]]></description><pubDate>2006-08-31T01:37:14-4294967289:00</pubDate></item><item><title><![CDATA[Less]]></title><link><![CDATA[http://explorer.altopix.com/map/q2vyaa/National_Radio_Astronomy_Observatory_GPS_Marker.htm#comments]]></link><author><![CDATA[explorer@altopix.com]]></author><description><![CDATA[The mark for Station 7617 is a point represented by the perpendicular intersection of a plane through the elevation axis with the azimuth axis of the NRAO VLBA (Very Long Base Array) antenna. The point is not accessible and cannot be occupied. No survey disk or mark designates the point. It should be noted that the antenna elevation axis is offset by 3.133 meters (7 feet) from the azimuth axis.

Reference Mark 1 is a punchmark in the rounded top of a 0.014 meter diameter stainless steel rod set 0.10 meters below ground. (NOTE: the punchmark is not set exactly on the top center of the rod, but approximately 1 to 2 mm toward the northeast. The rod is set in concrete in the center of a 0.15 meter diameter PVC pipe which is encased in a 0.5 x 0.6 meter concrete monument. The monument is covered with 0.18 meters of soil to the top of an aluminum logo cover attached to the top of the PVC pipe. The logo cover is stamped "7617 RM1". The monument is located 10.16 meters north of the NRAO site north fence corner and 8.65 meters south of the NRAO north property corner (iron pipe). It is set at a distance of 71.6 meters and at a geodetic azimuth of 346.1 degrees from Station 7617.

Reference Mark 2 is a punchmark in the rounded top of a 0.014 meter diameter stainless steel rod set 0.07 meters below ground. The rod is set in concrete in the center of a 0.15 meter diameter PVC pipe which is encased in a 0.34 meter diameter concrete monument. The monument is covered with 0.05 meters of soil to the top of an aluminum logo cover attached to the top of the PVC pipe. The logo cover is stamped "7617 RM2". The monument is located 11.02 meters northeast of the NRAO site east fence corner and 17.48 meters northeast of the NRAO east property corner (iron pipe). It is set at a distance of 42.1 meters and at a geodetic azimuth of 73.2 degrees from Station 7617.

Reference mark 3 is a standard NASA-GSFC brass disk. The disk is counter-sunk 0.015 to 0.020 meters and epoxied into a 0.37 x 0.67 meter section exposed lava outcropping. The disk is stamped "7617 RM3". The lava outcrop is located at the northeast base of a long sloping ridge line consisting of jagged broken lava rocks. it is set 27.08 meters south of the NRAO site south fence corner and 1.48 meters southwest of the NRAO south property corner (iron pipe). It is located at a distance of 53.4 meters and at a geodetic azimuth of 182.9 degrees from Station 7617.

One additional survey monument is set inside the fenceline of the NRAO site. It was designated "VLBA BM". The station mark is a 0.050 meter diameter brass disk set flush in the center of a 1.00 meter diameter concrete monument. The monument slopes up from ground level to 0.04 meters above the ground at the brass disk. The disk is unstamped. It is located 38.5 meters southeast of the centerline of the NRAO site entrance road/gate. 2.28 meters southeast of fence pole #12 as counted from the entrance gate southeast fence pole and 1.12 meters north of fence pole #13. It is set 0.87 meters northeast of the fenceline.]]></description><pubDate>2005-11-18T11:54:47-4294967289:00</pubDate></item></channel></rss>