MEMORANDUM FOR: Clifton S. Middleton
Project Director, Survey Section B
FROM: Captain Lewis A. Lapine, NOAA
Director, National Geodetic Survey
SUBJECT: INSTRUCTIONS: WISCONSIN FBN, 1997 (GPS-1207)
Task Numbers: 8K6D2000(FBN)
RK6C0400(ANA)
8K6D4000(CORS)
8K6D5000(IGLD)
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 components of the FBN. This survey will observe
the 22 FBN stations in Wisconsin and establish Primary Airport
Control Stations (PACS) at 78 airports in the state in support of
the FAA Area Navigation Approach (ANA) project. NGS will observe
the FBN and bench mark ties.
Also, 58 Cooperative Base Network (CBN) stations will be observed
by the Wisconsin Department of Transportation (WisDOT) to the
same specifications. WisDOT will also observe eight non-ANA
airport stations which NGS will process. Both NGS and WisDOT
will observe the non-FBN/CBN PACS.
In addition, at the St. Paul Continuously Operating Reference
Station (CORS) site, a pair of newly established CORS reference
marks is to be tied to both the local FBN/CBN and the CORS
antenna. The reference marks are STP1 A and Z 125.
One station at each of seven International Great Lakes Datum
(IGLD) water level sites in Wisconsin, Illinois, and Michigan
will be surveyed in this project. These seven sites are
located in Wisconsin at Green Bay, Sturgeon Bay, Kewaunee,
and Milwaukee, in Illinois at Chicago, and in Michigan at
Ludington and Holland. Reconnaissance for these sites is being
coordinated by Mr. Jeffrey Oyler, NOAA. Mr. Ronald Brewer,
Illinois Geodetic Advisor, will occupy the Chicago site.
To support software tests that will determine if FBN surveys can
be computed along with standard CORS processing, an additional
full-wavelength, dual-frequency Global Positioning System (GPS)
receiver is needed to act as a Central Temporary Continuously
Operating Reference Station (CTCORS) throughout the project. The
receiver shall be deployed at a relatively secure station
(preferably a PACS), within the vicinity of the ongoing observing
sessions. The receiver shall continuously collect data at a 30-
second epoch collection interval for 72 hours or more, before
being relocated.
Duplicate sets of raw GPS data and copies of the observation logs
for each station comprising the FBN portion of the project will
be forwarded by the NGS observers to Nancy Doyle, Spatial
Reference System Division, at least every 3 days. The FBN
portion of the project consists of FBN, FBN/PACS, bench marks,
CORS reference stations, and the CTCORS.
WisDOT will co-observe initially with five Ashtech dual-frequency
(Z-12) receivers. After the project begins, three Leica and two
Trimble dual-frequency receivers may be substituted for the
Ashtech receivers. At all times, WisDOT will co-observe with
five receivers. Before the project begins, the NGS field party
will provide training to the WisDOT personnel in the appropriate
procedures and specifications required to perform the survey.
The project will be performed under the technical management of
NGS. NGS will process all observational data in return for
WisDOT's participation.
PURPOSE:
In order to meet America's accelerating positioning and
navigation needs, the existing coordinate reference system
must be continually renovated and monitored 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, and 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.
PACS will provide local control to support future high-accuracy
ANA surveys of airport features and obstructions.
The reference marks established at the St. Paul 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
ties 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 stations and the local network. It
will also provide a check on the FBN/CBN, relative to the CORS
coordinates.
The IGLD survey will provide GPS-derived ellipsoid heights,
accurate to 2 cm, on IGLD Water Level Marks around the Great
Lakes.
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. The
CBN will follow the same specifications.
Data from the CORS in the region are to be used in the
processing. These CORS include Milwaukee (MIL1), St. Paul 1
(STP1), Wisconsin Point 1 (WIS1), Sturgeon Bay 1 (STB1), and
Upper Keweenaw 1 CORS L1 Phase Center (KEW1).
If possible, the first session of the B-order observations should
include an existing A-order or CORS station.
General specifications for the project are as follows. At each
FBN/CBN site, three sessions of 5 1/2 hours duration 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 4 hours different than 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. These same
specifications apply to the CBN.
For the IGLD stations, three 5-hour sessions are required, and
the observation times must be staggered over an approximate 12
hour period. (Suggested times are 7:00 a.m. to 12:00 noon, 9:30
a.m. to 2:30 p.m., and 1:00 p.m. to 6:00 p.m.) The seven
stations must be occupied continuously and simultaneously for
the entire 5-hour period, and they must be occupied with the same
type of receiver.
Specific to the St. Paul CORS project is that for the two
reference stations at the site and the nearest FBN/CBN station
(station OVERMAN in Minnesota), 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. The other receivers should occupy
Wisconsin stations as usual for the FBN/CBN survey, i.e., occupy
stations continuously for the 5 1/2 hour session. The CORS site
must be tied to the nearest FBN/CBN station (station OVERMAN in
Minnesota which Dixon Hoyle, Minnesota Geodetic Advisor, may be
able to occupy).
In general, station occupation and observing procedures must be
carried out according to appropriate sections of the "NGS
Operations Handbook," the current Trimble receiver field manuals,
and the appropriate field manuals for the Ashtech and Leica dual-
frequency receivers. 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. Success
in meeting the accuracy standards will be based on repeatability
of measurements, analysis of loop misclosures, adjustment
residuals, and comparison of results with standards external to
the project such as Eastern Strain Network measurements.
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 of stations (Table 1) and observing
scheme (Table 3) will be provided.
Data Acquisition - Data collection must be accomplished as
specified in the appropriate Trimble, Ashtech, and Leica 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 will be provided in Table 2.
(Sessions will generally begin at two observing windows 4 hours
apart - 1330 UTC and 1730 UTC. Each FBN and CBN must be occupied
twice at one time and once at the other.) Vectors between the
project stations shall be measured by single sessions consisting
of continuously and simultaneously tracking for 5 1/2 hours
(except as indicated above for the CORS reference marks).
Each FBN and CBN (including PACS that are FBNs or CBNs) must
be occupied at least three times - twice at one observing
window and once at the other observing window. Each FBN and
CBN must be tied to a bench mark in at least two sessions.
A different bench mark must be used for each of the two sessions.
PACS that are not FBNs or CBNs only need to be occupied twice.
However, each PAC needs both a bench mark tie and a FBN/CBN tie.
Bench marks as ties for FBNs, CBNs, and PACS only need to be
occupied once.
If FBNs are to be occupied in a session, at least two must be
occupied together (i.e., the FBN must be able to "stand on its
own.") Again, the observing scheme shall be arranged to ensure
that adjacent FBN and adjacent CBN stations are directly
connected in at least one observing session, and at least half of
all FBN and CBN base lines are repeated.
Also, some airports have existing B-order stations that were not
suitable as PACS. If possible, ties should be made between these
stations and the PAC at these airports.
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 controlled
airports.
Vector Computations for the FBN/CBN and Airport Stations -
Data management, quality review of collected data, and final
vector processing for the FBN/CBN survey will be accomplished by
the field party using OMNI. Vectors shall be computed in
theInternational Terrestrial Reference Frame (ITRF) system, using
the most current epoch and precise IGS ephemerides. Use
30-second epoch intervals, but 15-second epoch data may be used
if it improves ease of data processing. In all cases, integer
ambiguities will be fixed. Refer to Chapter 8 of the OMNI 3.42
manual for the latest techniques on fixing integers on medium and
long base lines. Refer to "DRAFT Final Processing Procedures"
dated January 1995 for specific information on data processing.
The quality of collected data shall be determined from the plots
generated from OMNI and by analysis of repeated vectors and free
adjustment residuals and/or loop misclosures (most loops
consisting of repeated vectors).
Survey Section B will perform all quality checks for conformance
to NGS format standards, including 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.
Vector Computations for the CORS and IGLD Sites - Data
management, quality review, and final vector processing will be
accomplished using OMNI. Vectors will be computed in the
International Terrestrial Reference Frame (ITRF) 1994, Epoch
1996.0, using precise IGS ephemerides. The GPS data and
positions for the CORS antennae are available from NOAA's CORS
GPS network. The CORS antenna will be used as the reference
station in the OMNI processing for each project.
The type of final solution, L1 versus ion-free, will depend on
the length of the vectors. For projects in which the vectors
from the CORS antenna to the other stations at the site are less
than 5 km in length, the final reduction will consist of a L1
fixed solution. For projects which include local FBN/CBN ties,
there may be vectors computed from the CORS antenna to the ties
which are greater than 5 km in length. These vectors will be
computed in a separate processing session from the short (less
than 5 km) vectors.
In general, vectors greater than 30 km in length are to be
computed in an ion-free fixed, or partially-fixed, solution. For
vectors between 5-30 km in length, compare both the L1 and ion-
free solutions to determine which has the best Post-Fit Residual
(PFR) plots. In all cases, integer ambiguities will be fixed for
each vector whenever possible. Refer to Chapter 8 of the OMNI
3.42 manual for techniques on fixing integers. The weather data
collected at each CORS site shall be averaged, and the average
values input into the MERGE program for all stations located at
the site.
The quality of collected data shall be determined from the plots
generated from OMNI and by analysis of repeated vectors and free
adjustment residuals and/or loop misclosures.
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 NAD 83 (Epoch 1996.0) position for the CORS
antennae will be used in the adjustments as the constraint. For
the other stations, compare the computed NAD 83 positions to the
published NAD 83 positions, if available.
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.
For the IGLD data, send a copy of the raw data and observation
logs to Nancy Doyle, Spatial Reference System Division, as soon
as they are received from the field personnel.
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 - Coordination must be maintained with the
following people who are involved in the project:
(1) Mr. Paul Hartzheim, WisDOT, who is assisting with the
Wisconsin FBN/CBN/PACS portion of the project,
(2) Mr. Glen Schaefer, WisDOT, who is assisting with the
Wisconsin FBN/CBN/PACS portion of the project,
(3) Dr. D. David Moyer, Wisconsin Geodetic advisor,
who is assting with the Wisconsin FBN/CBN/PACS
portion of the project,
(4) Mr. Ronald Brewer, Illinois Geodetic Advisor, who
will possibly occupy Illinois stations,
(5) Mr. Ronald Ramsey, Michigan Geodetic Advisor, who
will possibly occupy Michigan stations,
(6) Mr. Dixon Hoyle, Minnesota Geodetic Advisor, who
will possibly occupy station OVERMAN as the nearest
FBN/CBN tie for the St. Paul CORS site,
(7) Mr. Jeffrey Oyler, who can supply IGLD information,
and
(8) Messrs. Joe Lecner and Maurice Geiken,
points-of-contact for the St. Paul CORS site.
Antenna set-up is critical to the success of this project.
Fixed-height tripods are required 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.
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. In addition, a layout sketch of the CORS
and IGLD facilities should be made. Include the location of
the marks, antenna, buildings, and any other identifying
characteristics of the area on the sketch, as well as the
approximate height of the CORS antenna.
For each station visited, a visibility obstruction diagram must
be prepared and the TO-REACH description carefully checked for
errors or omissions.
Because of the different types of receivers being used in the
project, 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 September 16, 1997, will be provided. 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
"wiro097d.552". All records in connection with this project
shall be titled "WISCONSIN FBN, 1997". The project number
(accession number) is GPS-1207.
LIAISON:
Liaison must be maintained with designated offices at
the National Geodetic Survey headquarters located at:
1315 East-West Highway
Silver Spring, Maryland 20910
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, SSMC III, Station 8564
Telephone: 301-713-3215, ext. 117
Fax: 301-713-4327
e-Mail: mclemore@ngs.noaa.gov
Questions and problems concerning adjustment processing should be
directed to:
Maralyn L. Vorhauer
Observation and Analysis Division
N/NGS4, SSMC III, Station 8562
Telephone: 301-713-3176, ext. 104
Fax: 301-713-4327
e-Mail: maralyn@ngs.noaa.gov
Questions and problems concerning vector processing should be
directed to:
Juliana Blackwell
Field Operations Branch
Observation and Analysis Division
N/NGS41, SSMC III, Station 8458
Telephone: 301-713-3215, ext. 108
Fax: 301-713-4327
e-Mail: juliana@ngs.noaa.gov
Questions and problems concerning using CORS data in processing
should be directed to:
Neil Weston
Spatial Reference System Division
N/NGS2, SSMC III, Station 8622
Telephone: 301-713-3169, ext. 146
Fax: 301-713-4315
e-Mail: nweston@ngs.noaa.gov
The contact point for the duplicate set of NGS WI data that will
be sent to headquarters is:
Nancy S. Doyle
Global Positioning System (GPS) Branch
Spatial Reference System Division
N/NGS22, SSMC III, Station 8137
Telephone: 301-713-3208, ext. 159
Fax: 301-713-4324
e-Mail: nancy@ngs.noaa.gov
Questions and problems which could affect the technical adequacy
of the project should be directed to:
Stephen J. Frakes (Doug Hendrickson)
Chief, Project Development Branch
Spatial Reference System Division
N/NGS21, SSMC III, Station 8853
Telephone: 301-713-3194, ext. 111 (ext. 127)
Fax: 301-713-4316
e-Mail: steve@ngs.noaa.gov (dough@ngs.noaa.gov)
Coordination must be maintained with the following:
Paul J. Hartzheim
Wisconsin Department of Transportation
Surveying & Mapping Section, Room 5B
4802 Sheboygan Avenue
P.O. Box 7916
Madison, Wisconsin 53707
Telephone: 608-267-2462
Fax: 608-267-1859
e-Mail: hartzp@mail.state.wi.us
Glen Schaefer
Wisconsin Department of Transportation
Surveying & Mapping Section, Room 5B
4802 Sheboygan Avenue
P.O. Box 7916
Madison, Wisconsin 53707
Telephone: 608-266-8485
Fax: 608-267-1859
e-Mail: schaegr@mail.state.wi.us
D. David Moyer
University of Wisconsin
610 Walnut Street
1007 WARF Building
Madison, Wisconsin 53705
Telephone: 608-263-4834
608-266-3919
Fax: 608-267-1859
e-Mail: moyerd@mail.state.wi.us
Ronald K. Brewer
Illinois Department of Transportation
Aerial Surveys Section
2300 South Dirksen Parkway
Springfield, Illinois 62764
Telephone: 217-524-4890
Fax: 217-524-4149
e-Mail: r1k1b1@aol.com
Ronald L. Ramsey, NOAA/NGS
State Transportation Building
P.O. Box 30050
Design Survey Division
Lansing, Michigan 48909
Telephone: 517-377-1510
Fax: 517-335-2731
e-Mail: ramseyr@state.mi.us
For overnight delivery:
425 West Ottawa Street
Design and Survey Division
Lansing, Michigan 48909
Dixon Hoyle
Transportation Building, MS 641
395 John Ireland Boulevard
St. Paul, Minnesota 55155
Telephone: 612-296-1542
Fax: 612-297-1518
e-Mail: dixon.hoyle@dot.state.mn.us
For IGLD information, contact:
Jeff Oyler
NOAA, Atlantic Operations Section
808 Principal Court
Chesapeake, Virginia 23320-3639
Telephone: 757-436-0200
e-Mail: oyler@fob.noaa.gov
Contact the Points-of-Contact 3 or 4 days before arriving at the
CORS site. The Points-of-Contact for the St. Paul U.S. Army
Corps of Engineers (USACE) CORS Site are:
Joe Lecner
U.S. Army Corps of Engineers
Waterways Section
431 N. Shore Drive
P.O. Box 397
Fountain City, Wiconsin 54629-0397
Telephone: 608-687-4008
Fax: 608-687-8753
Maurice Geiken
U.S. Army Corps of Engineers
Electronic Service Center
1350 Dam Road
Hastings, Minnesota 55033-1145
Telephone: 612-437-2210
Fax: 612-437-8083
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/CBN expenses for this project will be charged to task number
8K6D2000. ANA expenses will be charged to RK6C0400. CORS
expenses will be charged to 8K6D4000. IGLD expenses will be
charged to 8K6D5000.
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, 1997.
ACKNOWLEDGMENT:
Please acknowledge receipt of these instructions in your Monthly
Report.
cc: N/CS - F. Maloney
N/NGS - S. Misenheimer*
N/NGS - W. Strange
N/NGS1 - G. Mitchell
N/NGS1X1 - R. Brewer
N/NGS1X1 - D. Moyer
N/NGS1x1 - D. Hoyle
N/NGS1X1 - R. Ramsey
N/NGS11 - S. Cofer
N/NGS2 - J. Till
N/NGS2 - N. Weston
N/NGS2 - D. Zilkoski
N/NGS21 - S. Frakes
N/NGS21 - R. Anderson
N/NGS21 - D. Hendrickson*
N/NGS22 - T. Soler
N/NGS22 - N. Doyle
N/NGS3 - E. Allen
N/NGS32 - S. Solbeck*
N/NGS4 - E. Wade
N/NGS41 - W. McLemore
N/NGS41 - J. Blackwell
N/NGS41 - D. Hoar
N/NGS6 - G. Mader
AMC - J. Albright*
FGCS Members*
NOS, NOAA - J. Oyler
Charlie Henderson, USCG
Alice Welch, Iowa Department of Transportation*
Paul Hartzheim, Wisconsin Department of Transportation
Glen Schaefer, Wisconsin Department of Transportation
Joe Lecner, USACE
Maurice Geiken, USACE
Bob Kunkel, Director, Wisconsin Bureau of Aeronautics
* 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).