FROM: Charles W. Challstrom
Acting Director, National Geodetic Survey
 

SUBJECT: INSTRUCTIONS: Field Reconnaissance for UTAH FBN, 1999 (GPS-1370)

Task Number: 8K6D2000
 

BACKGROUND:

The National Geodetic Survey (NGS), in accordance with the NGS Strategic Plan, is engaging in a campaign of observing stations of the Federal Base Network (FBN) to complete the ellipsoidal and orthometric height components of the FBN. Requirements for field reconnaissance to support the upcoming survey in Utah are outlined below.

The FBN in Utah consists of 26 stations (list and sketch included) that must be reconned. If a FBN station is not recoverable, a nearby station (preferably a bench mark) suitable for GPS should be recovered and the office informed.

Since Central Temporary Continuously Operating Reference Stations (CTCORS) throughout the state will be used in the GPS portion of the project, the reconn party should note which stations are suitable to serve as such (i.e., a receiver must be able to be left unattended for 24 hours a day for a several-day period).
 

RECONNAISSANCE SPECIFICATIONS:

Reconnaissance shall consist of a review of existing control, field recovery and mark maintenance, station selection, and compilation of updated station descriptions in standard NGS Blue Book format.
 

LIAISON:

For concerns regarding survey field operations, contact:

William T. McLemore, Jr.
Chief, Field Operations Branch, N/NGS41
PHONE: (301) 713-3215, ext. 117
FAX: (301) 713-4327
E-mail

For concerns regarding survey design or specifications, contact:

Stephen J. Frakes (Doug Hendrickson)
Chief, Project Development Branch, N/NGS21
PHONE: (301) 713-3194, ext. 111 (ext. 127)
FAX: (301) 713-4316
E-mail (E-mail)
 

DATA:

All records for this project shall be archived under the title "UTAH FBN, 1999" and accession number GPS-1370. Digital files shall be archived under filename "utro069.687".
 

REPORTS:

A summary of reconnaissance activities shall be included in the final project report.
 

ADDRESSES:

Keep N/NGS41 informed of the party's post office, physical address, and telephone number at all times.
 

PUBLICITY:

See NGS Operations Handbook, Section 1.4.1.
 

EXPENSES:

FBN expenses for this project will be charged to task number 8K6D2000.
 

TRAVEL:

Travel and per diem are authorized in accordance with Federal Travel Regulations, Part 301-11, Per Diem Expenses, and Appendix A to Chapter 301. Current per diem rates were effective January 1, 1999.
 

ACKNOWLEDGEMENT:

Please acknowledge receipt of these instructions in the Monthly Report and Journal.
 

cc: N/CS - N. Prahl
N/NGS - D. Zilkoski*
N/NGS - S. Misenheimer*
N/NGS1 - G. Mitchell
N/NGS1x1 - R. Cohen
N/NGS1x1 - D. Minkel
N/NGS1x1 - W. Stone
N/NGS11 - S. Cofer
N/NGS21 - S. Frakes
N/NGS21 - R. Anderson
N/NGS21 - D. Hendrickson*
N/NGS22 - T. Soler
N/NGS3 - E. Allen
N/NGS4 - E. Wade
N/NGS4 - D. Hoar
N/NGS41 - W. McLemore
N/NGS41 - J. Blackwell
N/NGS415 - G. Fredrick
FGCS Members*

Dennis Goreham, Utah Automated Geographic Reference Center
Dan Webb, Bureau of Land Management
Lyle Page, Utah Department of Transportation
Don Nay, Utah County
Ed Bell, Salt Lake County
Von Hill, Hill, Jamison, and Assoc., Inc.
Don Bloodworth, Arizona Department of Transportation
Connie Brown, Arizona Department of Transportation
Phil Tuwaletstiwa, Hopi Tribe
Lemont Yazzie, Navajo Nation
Dean Wiese, Bureau of Land Management
Stuart Lane, Mohave County Public Works
Jerry Lumsden, U.S. Bureau of Reclamation
Bernard Kelly, Idaho Transportation Department
Timothy Wolf, Las Vegas Valley Water District
Mike Londe, Bureau of Land Management
Carl Sumpter, Medicine Bow - Routt National Forest

* first page only

FROM:
Charles W. Challstrom
Acting Director, National Geodetic Survey

SUBJECT:
INSTRUCTIONS: UTAH FBN, 1999 (GPS-1370)
Task Number:  8K6D2000 (FBN)
 

GENERAL:

The National Geodetic Survey (NGS), in accordance with the NGS Strategic Plan, is engaging in a campaign of observing stations of the Federal Base Network (FBN) to complete the ellipsoidal and orthometric height components of the FBN.  This survey will  observe the 26 FBN stations in Utah.  This campaign will be continuous and will tie into adjoining states.  (Some states will be skipped for seasonal relocations.)

In addition, at the Red Butte Continuously Operating Reference Station (CORS) site, a pair of CORS reference marks is to be tied to both the local FBN/CBN and the CORS antenna.  The reference marks are RBUT A (PID AE4749) and RBUT B (PID AE4747).  The FBN/CBN tie station to use is PIERCE (PID AA3690).  The backup tie station is ZLC B (PID AA3701).

Lastly, absolute gravity station X 27 (PID LN0323) has been added to the project and is to be surveyed to FBN specifications.

A full-wavelength, dual-frequency Global Positioning System (GPS) receiver is needed to act as a Central Temporary CORS (CTCORS) where there are no existing CORS within 300 km of the ongoing observations.  The receiver shall be deployed at a relatively secure station within the vicinity of the ongoing observing sessions.  The receiver shall continuously collect data at a 30- second epoch collection interval for a minimum of 72 hours and for as long as observations are ongoing in the vicinity of the  CTCORS.  (Even if there is an existing CORS within 300 km of the ongoing observations, deploy a receiver at a relatively secure station and collect data for 72 hours or more.)

Mr. Gary Means, NGS field coordinator for the project, is coordinating the co-observing by various organizations of approximately 30 to 40 additional Cooperative Base Network (CBN) stations that are also to meet the FBN specifications for this project.  (One of these stations will be at the Four Corners border.)  The project will be performed under the technical management of NGS.

PURPOSE:

In order to meet America's accelerating positioning and navigation needs, the existing coordinate reference system must be continually enhanced to provide the accessibility and high accuracy required for use with GPS.  The digital revolution in mapping, charting, and surveying requires a National Spatial Reference System (NSRS) consisting of, among other components, a network of monumented points having four-dimensional positions.  The FBN fulfills the requirements for this component.  NGS is charged with the Federal responsibility for establishment, observation, monitoring, and maintenance of the FBN.  The FBN provides the critical network foundation for an accurate, consistent, reliable NSRS.

The NSRS, in turn, provides the common geographic framework for America's spatial data infrastructure.  As such, the NSRS serves as the basis for mapping, charting, navigation, boundary determination, property delineation, infrastructure development, resource evaluation surveys, and scientific applications, including crustal motion monitoring, modeling of flooding, storm surge, pollution trajectories, and agricultural runoff.  A modernized, accurate, consistent, reliable NSRS is of enormous benefit to state, county, tribal, local, and Federal authorities, as well as to the private sector.

The reference marks established at the Red Butte CORS site will provide a very accurate tie to the antenna as an aid to reposition the antenna should that become necessary.  The FBN/CBN tie to the CORS marks will also provide site station coordinates relative to the local FBN/CBN, thus reducing the potential for relative error between the reference marks and the local network. It will also provide a check on the FBN/CBN, relative to the CORS coordinates.

SPECIFICATIONS:

Project requirements for the FBN observations are to ensure 2- centimeter local accuracy in the horizontal component, as well as 2-centimeter local accuracy for the ellipsoid heights.

Data from the CORS in the region are to be used in the processing.  There is one NGS CORS in Utah and eight Basin and Range Geodetic Network (BARGN) CORS in Nevada and Utah combined. (Six BARGN CORS are in Utah and two are in Nevada.)  Also, there are three CORS in Utah operated by the University of Utah.  There is one NOAA CORS in New Mexico near the Four Corners border.

The NGS CORS in Utah is Red Butte (RBUT). The six BARGN CORS in Utah are (only id available): FOOT, SMEL, CAST, HEBE, COON,  and CEDA.  The two BARGN CORS in Nevada are GOSH and EGAN.  The three University of Utah CORS in Utah are East Ogden (EOUT), Lake Mountain (LMUT), and North Antelope Island (NAIU).  The name of the NOAA CORS in New Mexico near Four Corners is AZTEC (AZCN).

Positions and data for the NGS CORS are available from the NGS web site.  Contact Mr. Jim Normandeau, listed under LIAISON to obtain the BARGN CORS data; contact Mr. Robert Smith, again under LIAISON to obtain data from the three University of Utah CORS.   Data from the NOAA CORS in New Mexico is also available from the NGS web site.  Positions for the BARGN and University of Utah  CORS will be provided by Ms. Vasanthi Kammula of the Network Analysis Branch, N/NGS23 (see LIAISON).

It should be noted that there is a 30-day delay in the availability of the BARGN CORS data.

General specifications for the project are as follows.  At each FBN site, three sessions of 5 ½ hours duration for each session shall be observed.  The observing scheme shall be arranged so that for each station, the start time of one of the observing sessions shall be at least 4 hours different from the other two.  The observing scheme shall be arranged to ensure that adjacent FBN stations are directly connected in at least one observing session, and at least half of all base lines are repeated.

Specific to the Red Butte CORS site is that for the two  reference marks at the site, two sessions of 2 hours each shall be observed.  In order to provide a check, the equipment shall be broken down and reset with a minimum of 30 minutes between the two sessions.  Since the CORS site must be tied to the nearest FBN/CBN station, FBN/CBN tie station PIERCE (or backup station ZLC B) must be occupied simultaneously with the two reference marks.  The equipment breakdown and reset requirement of at least 30 minutes is also required for station PIERCE (or ZLC B, if that station is used).

In general, station occupation and observing procedures must be carried out according to appropriate sections of the "NGS Operations Handbook" and the current applicable receiver field manuals.  Data formats and digital file definitions are given in "Input Formats and Specifications of the National Geodetic Survey Data Base," Volume I. Horizontal Control Data, Federal Geodetic Control Subcommittee, September 1994, revised and reprinted November 1998.  Success in meeting the accuracy standards will be based on repeatability of measurements, analysis of loop misclosures, and adjustment residuals.

General specifications for the project are given in "Geometric Geodetic Accuracy Standards and Specifications for Using GPS Relative Positioning Techniques," Version 5.0:  dated May 11, 1988, reprinted with corrections August 1, 1989.  Specific project criteria and deviations from the general specifications are given in the following sections.

Project Network - A list (Table 1) and sketch of stations involved in this project will be provided.
Data Acquisition - Data collection must be accomplished as specified in the appropriate dual-frequency receiver field manuals in the compressed mode at a 15-second epoch collection interval.  The GPS receivers must be dual-frequency and full- wavelength.  Track satellites down to a 10-degree elevation angle.

The satellite observing scenario has been provided in Table 2. Sessions will generally begin at two observing windows at least 4 hours apart - 1530 UTC and 1930 UTC.  Vectors between the project stations shall be measured by single sessions consisting of continuously and simultaneously tracking for 5 ½ hours.

Each FBN station must be occupied at least three times - twice at one observing window and once at the other.  Each FBN station must be tied to a bench mark in at least two sessions.  A different bench mark must be used for each of the two ties.   Adjacent FBN stations must be directly connected in at least one observing session, and at least one-half of all FBN base lines must be repeated.  The CORS base lines will be repeated.  CORS and CTCORS data will be used throughout the project.

For this project, each CBN station must also be occupied three times as described above.  However, CBN stations can be tied to adjacent FBN stations (if the FBN station is closer than a CBN station), and a base line consisting of a CBN station and a FBN station can be used in the repeated-base line requirement mentioned above for the CBN portion of this project.

Record weather data just before, immediately after, and at the mid-point of each session.  Meteorological data shall also be collected immediately after an obvious weather front passes during a session and immediately before it passes, if possible.  Pressure and relative humidity measurements must be made near and at about the height of the GPS antenna phase center.  Indicate in the log the location of the barometer and psychrometer.

Survey operations shall be conducted with due regard to the safety of personnel and equipment.  Contact with the airport traffic control tower is mandatory during surveys at any controlled airports.

Vector Computations - Data management, quality review of collected data, and final vector processing for the FBN survey will be accomplished by the field party using PAGES.  Vectors shall be computed in the International Earth Rotation Service Terrestrial Reference Frame (ITRF) system, using the most current epoch and precise IGS ephemerides.  Use 30-second epoch intervals for data processing.  Monument positions will be used for CORS when available, otherwise, antenna reference point (ARP) positions will be used.   For stations where weather data are not available, or are suspect, predicted values computed based on the station's latitude, height above mean sea level, and time and day of year will be used.  Use 15 degrees as the cutoff elevation angle in data processing.  A cutoff angle of 10 degrees may be used when necessary to improve results.

The type of final solution, L1 versus ion-free, will depend on the length of the vectors.  For vectors which are less than 10 km in length, the final reduction will consist of a L1 fixed solution.  These vectors will be computed in a separate processing session from the longer vectors computed in an ion- free solution.

In general, vectors greater than 10 km in length are to be computed in an ion-free fixed, or partially-fixed, solution.  In all cases, integer ambiguities will be fixed for each vector whenever possible.

For the Red Butte CORS reference marks, the CORS antenna at the site will be used as the reference station in the data processing.

The quality of collected data shall be determined from the plots generated from PAGES, by analysis of repeated vectors and/or comparison of station positions, and free adjustment residuals and/or loop misclosures.  In addition, a constrained adjustment constraining all CORS will be performed.

Survey Section B will perform all quality checks for conformance with NGS format standards such as executing software programs COMPGB, OBSCHK, and OBSDES.  The final ITRF vectors will be assessed and transformed to the NAD 83 coordinate system using program ADJUST.

The data and results will be submitted to the Observation and Analysis Division.  All B-files and G-files must be complete, including *25* and *27* records.

Station Descriptions - Station recovery notes must be submitted in computer-readable form using DDPROC software.  Include the name, address, and telephone number of a property owner or other contact.

Special Requirements - Antenna set-up is critical to the success of this project.  Fixed-height tripods are preferred for all receivers.  The plumbing bubbles on the antenna pole of the fixed-height tripod must be shaded when plumbing is performed.  They must be shaded for 3 minutes before checking and/or re- plumbing.  Also, the perpendicularity of the poles must be checked at the beginning of the project and any other time there is suspicion of a problem.

When a fixed-height tripod is not used, the height of the antenna must be carefully measured to prevent station set-up blunders from occurring.  Tribrachs used for these set-ups must be checked and adjusted when necessary.  Totally independent measurements of the antenna height above the mark in both metric and English units must be made before and after each session.  Someone other than the observer must check the measurement computations by carefully comparing measurements and then entering his/her initials on the log.

Some GPS antennas have detachable ground planes and radomes.  In order to help identify what exactly was used at a particular site, it would be useful to have a snapshot of the setup.  All co-observers, please take a photograph of the setup, if possible, with a close-up of the antenna as viewed from the side.

In addition, a rubbing of the stamping of the mark must be made at each visit to a station.  If it is impossible to make a rubbing of the mark, a plan sketch of the mark must be substituted, accurately recording all markings.

Also, for each station visited, a visibility obstruction diagram must be prepared and the TO-REACH description carefully checked for errors or omissions.

Lastly, the following must be recorded at each occupation of a station:

     (1) receiver manufacturer,
     (2) antenna manufacturer,
     (3) receiver model number (part number),
     (4) antenna model number (part number),
     (5) the complete serial number of the receiver, and
     (6) the complete serial number of the antenna.

Success of this project requires that the highest quality GPS data be collected.  Therefore, during each station occupation, the operators shall carefully monitor the operation of the receivers.  Any irregularities in the data due to equipment malfunction, DOD adjustment of the satellite orbit, obstructions, etc., must be reported to the Field Operations Branch, N/NGS41, as soon as possible and noted on the observing log.  If the quality of observations for an observing session is questionable, notify the Field Operations Branch immediately.

The survey team shall not depart the project area until they have quality reviewed all data, advised N/NGS21, and notified N/NGS41.

GPS DATA:

Visibility tables and plots of the present satellite constellation for June 7, 1999, have been reviewed and two observing windows selected.  For operational use, current data must be generated with Trimble mission planning software or from program SATMAP.

Project report and data listed in Annex L of "Input Formats and Specifications of the NGS Data Base" and in the attached addendum for the adjustment portion must be transmitted.  Any data considered suspect as to quality in achieving accuracy standards should be sent via FedEx immediately for office review.  Backup of transmitted data must be held until notified by the Field Operations Branch, N/NGS41.

The data set collected during the project shall be named "utro069d.687".  All records in connection with this project shall be titled "UTAH FBN, 1999".  The project number (accession number) is GPS-1370.

LIAISON:

Liaison must be maintained with designated offices at the  National Geodetic Survey headquarters located at:

          1315 East-West Highway
          Silver Spring, Maryland  20910-3282

Questions and problems concerning survey field operations should be directed to:

          William T. McLemore, Jr.
          Chief, Field Operations Branch
          Observation and Analysis Division
          N/NGS41
          Telephone:  301-713-3215, ext. 117
          Fax:  301-713-4327
            E-mail

Questions and problems concerning adjustment processing should be directed to:

          Maralyn L. Vorhauer
          Observation and Analysis Division
          N/NGS4
          Telephone:  301-713-3176, ext. 104
          Fax:  301-713-4327
           : E-mail

Questions and problems concerning vector processing should be directed to:

          Juliana Blackwell
          Field Operations Branch
          Observation and Analysis Division
          N/NGS41
          Telephone: 301-713-3215, ext. 108
          Fax: 301-713-4327
           : E-mail

Questions and problems concerning using CORS data in processing should be directed to:

          Neil Weston
          Geosciences Research Division
          N/NGS6
          Telephone:  301-713-2847, ext. 202
          Fax:  301-713-4475
           : E-mail

To obtain positions for the BARGN and University of Utah CORS, contact:

          Vasanthi Kammula
          Network Analysis Branch
          Spatial Reference System Division
          N/NGS23
          Telephone: 301-713-3197, ext. 115
          Fax: 301-713-4324
           : E-mail

Questions and problems which could affect the technical adequacy of the project should be directed to:

  Stephen J. Frakes (Douglas Hendrickson)
          Chief, Project Development Branch
          Spatial Reference System Division
  N/NGS21
  Telephone:  301-713-3194, ext. 111 (ext. 127)
          Fax:  301-713-4316
            E-mail (E-mail)

The field coordinator for the project is:

          Mr. Gary Means
          National Geodetic Survey
          Field Operations Branch
          538 Front Street
          Norfolk, Virginia 23510
          Telephone: 757-441-6264
           : E-mail

Tentative contacts for the CBN are:

          Jim W. Pierce
          Salt Lake County Surveyor's Office
          2001 South State, Suite N1500
          Salt Lake City, Utah 84190-1350
          Telephone: 801-468-2044
            E-mail

          Ross Workman
          Land Surveyor
          Utah State Office
          P.O. Box 45155
          Salt Lake City, Utah 84145-0155
          Telephone: 801-539-4155
          Fax: 801-539-4134
            E-mail

          Cindy Lou McDonald
          Geographic Information Specialist
          Carbon County
          120 East Main
          Price, Utah 84526
          Telephone: 435-636-3265
          Fax: 435-636-3210
           : E-mail

          David F. Hanrion
          C/o LarWEST Engineering & Surveying
          1770 North Research Park Way
          Suite 130
          North Logan, Utah 84341
          Telephone: 800-876-0153
          Fax: 435-753-0619
            E-mail

          Curt Neilson
          Cedar City Corp.
          P.O. Box 249
          Cedar City, Utah 84721
          Telephone: 435-586-2963
          Fax: 435-586-4362
          nbsp;: E-mail

          Ernest D. Rowley, PLS
          Chief Deputy Weber County Survey
          2380 Washington, Blvd., Suite 260
          Ogden, Utah 84401
          Telephone: 801-399-8020
          Fax: 801-399-8316
           : E-mail

The e-Mail and web site addresses for obtaining NBAR CORS data are:

          Mr. Jim Normandeau
           : E-mail
          web site: http://lox.ucsd.edu/permanentGPSSites

The e-Mail and web site addresses for obtaining University of Utah CORS data are:

          Mr. Robert B. Smith
           : E-mail
          web site: http://www.mines.utah.edu/~rbsmith/RESEARCH/UUGPS.html

Names and telephone numbers of local contacts are given in the station description material.

ADDRESS:

Keep N/NGS41 informed of the party's post office, physical address, and telephone number at all times.

PUBLICITY:

See "NGS Operations Handbook," Section 1.4.1.

EXPENSES:

FBN expenses for this project will be charged to task number 8K6D2000.

TRAVEL:

Travel and per diem are authorized in accordance with Federal Travel Regulations, Part 301-7, Per Diem Allowances.  Current per diem rates were effective January 1, 1999.

ACKNOWLEDGMENT:

Please acknowledge receipt of these instructions in your Monthly Report.

Attachment

cc:  N/NGS - D. Zilkoski*
     N/NGS - S. Misenheimer*
     N/NGS1 - G. Mitchell
     N/NGS1x1 - R. Cohen
     N/NGS1x1 - D. Minkel
     N/NGS1x1 - W. Stone
     N/NGS11 - S. Cofer
     N/NGS21 - S. Frakes
     N/NGS21 - R. Anderson
     N/NGS21 - D. Hendrickson*
     N/NGS22 - T. Soler
     N/NGS3 - E. Allen
     N/NGS4 - E. Wade
     N/NGS4 - M. Vorhauer
     N/NGS4 - D. Hoar
     N/NGS41 - W. McLemore
     N/NGS41 - J. Blackwell
     N/NGS412 - G. Means
     N/NGS415 - G. Fredrick
     N/NGS5 - R. Snay
     N/NGS6 - N. Weston
     FGCS Members*

     Dennis Goreham, Utah Automated Geographic Reference Center
     Dan Webb, Bureau of Land Management
     Lyle Page, Utah Department of Transportation
     Don Nay, Utah County
     Ed Bell, Salt Lake County
     Von Hill, Hill, Jamison, and Assoc., Inc.
     Jim Pierce, Salt Lake County Surveyor's Office
     Ross Workman, Utah State Office
     Cindy Lou McDonald, Carbon County
     David Hanrion, LarWEST Engineering & Surveying
     Curt Neilson, Cedar City Corp.
     Ernest Rowley, Weber County Survey
     Don Bloodworth, Arizona Department of Transportation
     Connie Brown, Arizona Department of Transportation
     Phil Tuwaletstiwa, Hopi Tribe
     Lemont Yazzie, Navajo Nation
     Dean Wiese, Bureau of Land Management
     Stuart Lane, Mohave County Public Works
     Jerry Lumsden, U.S. Bureau of Reclamation
     Bernard Kelly, Idaho Transportation Department
     Timothy Wolf, Las Vegas Valley Water District
     Mike Londe, Bureau of Land Management
     Carl Sumpter, Medicine Bow - Routt National Forest

* first page only

DATA TO BE SENT TO HEADQUARTERS RELATING TO THE ADJUSTMENT PORTION OF THE PROJECT

Note that all except specified files or listings can be paper printouts or ASCII files on disk; be sure to keep backups until notified that the data base is loaded.

Free adjustment.

[For A- and B-order projects, the data are not scaled.  First- order projects would also have a free adjustment using the modified G-file.]

Constrained horizontal adjustment holding previously published A- and B-order stations and ellipsoid heights (optional).

Constrained vertical adjustment holding NAVD 88 heights.

Final combined Blue Book file (ASCII required).

Free adjustment with accuracies.

Accuracy listing (output of BBACCUR).  (Paper required).

ELLACC output.

OBSCHK output*.

CHKDESC output*.

OBSDES output*.

*any errors or warning messages must be explained.

Copies of data used to determine fixed control, both horizontal and vertical.

Final description file (ASCII required).

Final G file (ASCII required).