Oregon GPS Users Group

Subject: Oregon GPS Users Group Content-Type: multipart/mixed; boundary="------------3131330723DC" Status: RO X-Status: This is a multi-part message in MIME format. --------------3131330723DC Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit http://www.teleport.com/~kchamber/welcome.htm --------------3131330723DC Content-Type: text/html; charset=us-ascii; name="welcome.htm" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="welcome.htm" Content-Base: "http://www.teleport.com/~kchamber/welc ome.htm" Oregon GPS Users Group

Oregon GPS Users Group

Next Meeting Thursday, January 22, 1998

Last Update of this Page: 1-14-98

The Oregon GPS Users Group is now hosting the 1998 Oregon High Accuracy Reference Network Home Page. Here you will find information about this project; including reconnaissance status, station recovery and observation forms, and schedules.
This site is under construction: Please check back often for new information.

The Oregon GPS Users Group was established in 1988 to promote the use and understanding of GPS for surveying and mapping in the State of Oregon. The Users Group membership is made up of GPS users from the private sector as well as from city, county, and Federal governments. Presently the group is co-chaired by Ken Bays, of the U.S. Bureau of Land Management, Oregon State Office, and Ken Chamberlain, of the US Forest Service, Pacific Northwest Region. Curtis Smith, the new National Geodetic Survey Adviser for Oregon, also works closely with the Users Group.

One of the first missions of the User Group was to promote the completion of an order-B GPS High Accuracy Reference Network (HARN) in the State of Oregon. User Group members cooperated to forge funding agreements and to perform reconnaissance, monumentation, and leveling to establish the network. The National Geodetic Survey performed the GPS observations, and then adjusted and published the final positions in the National Spatial Reference System referenced to the North American Datum of 1983 (1991 adjustment). The Oregon HARN network has served as a valuable resource for GPS users in Oregon, providing B-order horizontal control survey stations that are easily accessible and usable for GPS. In 1998, the National Geodetic Survey will be reobserving that portion of the HARN that is made up of Federal Base Network stations, and the Oregon GPS Users Group is coordinating simultaneous reobservations of that portion of the HARN that is made up of Cooperative Base Network stations. Please check out our home page for the 1998 HARN observation campaign..

Current Projects:

GPS Survey Specifications

One goal of the User Group is to promote standards for GPS surveying and mapping. A subcommittee of the group has been formed to review existing specifications and guidelines used around the country. Listed below are some of the background documents we will be working with to develop GPS Specifications for optional use in our state.

The Federal Geodetic Control Subcommittee (FGCS) has written up the draft document "GeospatialPositioning Accuracy Standards", and has recommended their adoption by the Federal Geographic Data Committee. They released the document for a period of public review and comment ending May 15, 1997. The purpose of these standards is to provide a common accuracy standard model for many geographic data types, so that the accuracy of any geographic data type can be evaluated in comparison to another geographic data type.

Requests for written copies of the standards can be obtained by contacting: Geospatial Positioning Accuracy Standards Review, FGDC Secretariat, (Attn Jennifer Fox), US Geological Survey, 590 National Center, 12201 Sunrise Valley Drive,Reston, VA, 22092; 703-648-5514; fax: 703-648-5755; e-mail:gdc@usgs.gov. The standards may also be downloaded from the Internet at URL "http://www.fgdc.gov/pub/standards/Accuracy/" These standards do not contain the specifications for methodology and equipment which are required to achieve a certain accuracy standard.

The California Geodetic Control Committee has written the Specifications for Geodetic Control Networks Using High-Production GPS Surveying Techniques which provide guidelines for GPS methodology and equipment. These specifications build on the outdated FGCS document "Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques", version 5.0, May 1988, reprinted with corrections August 1, 1989. This 1989 document was widely distributed and used; however, it was never formally adopted by the Federal Geodetic Control Subcommittee. The California Specifications update certain portions of the 1989 FGCS standards which are out of date due to GPS equipment and methodology advances.

Click here to download California High Production GPS Specifications: hpgpsmsw.exe is a MS Word v.7 format| hpgpswpd.exe is a Word Perfect v.6.1 format

GPS Training

The Oregon GPS Users Group, with help from the Washington GPS Users Group and the Lower Columbia Chapter of the Land Surveyors Association of Washington, sponsored a one day workshop on GPS-derived Orthometric Heights on June 6, 1997. The workshop covered vertical datums, Geoid96 use, and the development and use of the NGS guidelines for 2 and 5 cm height determinations. The Oregon Users Group thanks the instructors Dave Zilkoski and Dru Smithof the National Geodetic Survey. They did an excellent job!

We plan on sponsoring other workshops in the future, so please email your suggestions for topics and/or instructors.

Upcoming GPS Training in Oregon.

What's New:

Corpscon, V. 5

The U.S. Army Topographic Engineering Center, Geospatial Engineering Branch has a new version of Corspscon. Corpscon, Version 5.x, is a MS-Windows-based program which allows the user to convert coordinates between Geographic, State Plane and Universal Transverse Mercator (UTM) systems on the North American Datum of 1927 (NAD 27), the North American Datum of 1983 (NAD 83) and High Accuracy Reference Networks (HARNs). Corpscon uses the National Geodetic Survey (NGS) program Nadcon to convert between NAD 27, NAD 83 and HARNs. Corpscon, Version 5.x, performs vertical conversions to and from the National Geodetic Vertical Datum of 1929 (NGVD 29) and the North American Vertical Datum of 1988 (NAVD 88). Vertical conversions are based on the NGS program Vertcon and can be performed for the continental U.S. only. Corpscon, Version 5.x, will also calculate geoid-ellipsoid separations based on the NGS program Geoid96. Geoid-ellipsoid separations can be calculated for the Continental U.S., Alaska, Hawaii and Puerto Rico/U.S. Virgin Islands. Click here to download free from the following Internet site: http://calvin.tec.army.mil/.

The Continuously Operating Reference Station (CORS) in Appleton, Washington is now operational: It is located in southern Washington, northwest of The Dalles, Oregon, just north of the Columbia River Gorge, and is operated by the Federal Railroad Administration. GPS differential corrections are broadcast at 300 watts from a 300 ft. tower. Early reports have indicated reception as far as Medford, Oregon (about 250 mountainous miles) with very strong reception in the Portland Metro area and the Willamette Valley. Oregon GPS User Group Appleton CORS Page

In order to better determine customer needs and to avoid confusion between antenna L1 phase center (L1PC) and antenna reference point (ARP) coordinates, the National Geodetic Survey (NGS) is providing a questionnaire for users or potential users of their Continuously Operating Reference Stations(CORS) .

Next Meeting is a joint meeting of

the Oregon & Washington GPS User Groups

Thursday, January 22, 1998

10:00 AM

USGS Cascades Volcano Observatory

5400 MacArthur Blvd.

Vancouver, WA 98661

click here for a meeting agenda

Please email your suggestions for meeting agenda .

Minutes of November 7. 1997 meeting

Minutes of September 10, 1997 meeting