# Presentation: 270280

## North DakotaWorkshop

- Kathy Milbert
- December 2003

## The North Dakota NetworkOutline of Topics for Discussion

- Past & Present
- Original HARN (1996)
- FBN/CBN (2002)-Planning, Observations & Reductions
- FBN/CBN (2002)-Adjustment Results
- Statewide GPS Readjustment of Ellipsoid Heights

## The North Dakota NetworkMore Topics

- Future
- Overview of National Readjustment Strategy
- North Dakota’s fit into the Readjustment Plan
- Expected impact of NAD83 (NSRS) National Readjustment on the North Dakota Network
- Local & Network Accuracies

## North Dakota’s Geodetic NetworkHistorical Overview

- NAD83 (86)-National Readjustment/Classical
- NAD83 (96)-High Accuracy Reference Network (HARN)
- Statewide Readjustment NAD83 (96)
- Both Classical & GPS
- FBN/CBN Re-Observations/2002
- Statewide GPS Readjustment of Ellipsoid Heights

## North Dakota HARN (1996)

- A Order Portion (1:10,000,000)
- 9 Stations
- Trimble Receivers
- Three 5 and 1⁄2 hour sessions
- September 23, 1996 through October 4, 1996
- Omni Reductions

## Slide 6

## North Dakota HARN (1996)

- B Order Portion (1:1,000,000)
- 68 Stations
- Trimble Receivers
- Two 5 and 1⁄2 Hour Sessions
- October 7, 1996 through November 29, 1996
- Omni Reductions

## Slide 8

## North Dakota HARN (1996)Adjustment Results

- A Order-Free Adjustment
- Largest Horizontal Residual 	**0.0179 m**
- Vertical Residual Spread	 **-0.0263 m to 0.0294 m**
- A Order-Constrained Adjustment
- Largest Horizontal Residual	**0.0422 m**
- Vertical Residual Spread	 **-0.0525 m to 0.0885** **m**

## North Dakota HARN (1996)Adjustment Results

- B Order-Free Adjustment
- Largest Horizontal Residual 	**0.0081 m**
- Vertical Residual Spread	 **-0.0258 m to 0.0304 m**
- B Order-Constrained Adjustment
- Largest Horizontal Residual	**0.0245 m**
- Vertical Residual Spread	 **-0.1466 m to 0.0857** **m**

## North Dakota HARN (1996)Adjustment Results

- Horizontal Component
- Constrained adjustment looks OK
- Vertical Component
- Constrained adjustment looks BAD

##  What Happened?

**PROBLEMS CAUSED BY THE CONTROL**
- There were no CORS stations used as control
- What Control was Used?
- The South Dakota B Order HARN (1996)
- The Minnesota B Order HARN (1994-1996)
- The Eastern Strain A Order Project (1993)
- The ID/MT A & B Order HARN (1991**)**
- Our application of GPS Technology was limited in the early 1990’s

## How Big is this Problem Nationwide?

- Large discontinuities (greater than 5 cm) between the HARN and CORS have been detected in almost every state in the height component
- In some states there are also large discontinuities (greater than 5 cm) in the horizontal component but these are not nearly as prevalent as in the heights

## FBN Re-Observation/Height Component

- The statewide re-observation of the FBN/CBN network (1997 to 2003) provides the necessary foundation to resolve network deficiencies
- The latest GPS technology is used for the observations and reductions
- Network ties are made between CORS stations and HARN stations

## The North Dakota FBN/CBN Survey2002

- 2 cm Local Accuracy Requirement for horizontal and ellipsoid height components
- Trimble Receivers
- Three 5 and 1⁄2 hour sessions in state
- One 5 and 1⁄2 hour session across state boundaries
- 59 Stations
- 4 CORS Stations + 1 ACS Station
- 29 Ties to North Dakota HARN
- Additional Ties to MN (3) & MT (4) FBN/CBN’s
- May 20, 2002 through June 14, 2002

## Slide 16

## Who made it happen?

- Observations
- NGS-Cliff Middleton-Party Chief
- Ulteig Engineering
- Kadrmas, Lee & Jackson
- U.S Forest Service
- Ducks Unlimited, Inc.
- Moore Engineering
- The Coteau Properties Co.
- Houston Engineering Inc.
- City of Fargo, Engineering Dept.
- Interstate Engineering Inc.

## Who else made it happen?

- Project Coordinator and GPS Reductions Using Pages:
- Gary Means
- Project Adjustment:
- Kathy Milbert

## North Dakota FBN SurveyAdjustment Results

- Free Adjustment
- Largest Horizontal Residual 	0.0152 m
- Vertical Residual Spread	  -0.0239 m to 0.0256 m
- CORS Coordinates Constrained Adjustment
- Largest Horizontal Residual	0.0269 m
- Vertical Residual Spread	  -0.0353 m to 0.0389 m

## CORS Adjustment versus Published HARN Coordinates

**Station Name****	****	****Position Diff (m)****	****EH Diff (m)**
**5N8****	****	****	****0.018****	****	****	****0.024**
**ARROWWOOD****	****	****0.026****	****	****	****0.000**
**D 477****	****	****	****0.021****	****	****	****0.029**
**D 499****	****	****	****0.023****	****	****	****0.024**
**DAISY****	****	****	****0.013****	****	****	****0.047**
**DAKOTA****	****	****	****0.022****	****	****	****0.013**
**E 486****	****	****	****0.020****	****	****	****0.050**
**FAA D50 A****	****	****0.021****	****	****	****0.044**
**FAA HEI A****	****	****0.025****	****	****	****0.089**
**FAA ND17 A****	****	****0.021****	****	****	****0.026**
**G 26****	****	****	****0.029****	****	****	****0.014**
**G 304****	****	****	****0.015****	****	****	****0.026**
**H 502****	****	****	****0.021****	****	****	****0.075**
**ISN A****	****	****	****0.018****	****	****	****0.132**
**J 468****	****	****	****0.014****	****	****	****0.079**

## CORS Adjustment versus Published HARN Coordinates  

**Station Name****	****	****Position Diff (m)****	****	****EH Diff (m)**
**J 474****	****	****	****   0.017****	****	****	****0.059**
**J 491****	****	****	****   0.013****	****	****	****0.072**
**K 478****	****	****	****   0.024****	****	****	****0.024**
**M 9****	****	****	****   0.017****	****	****	****0.048**
**MOHALL APT****	****	****   0.013****	****	****	****0.062**
**PEMBINA APT AZ MK****	****   0.022****	****	****	****0.022**
**PIMPLE****	****	****   0.014****	****	****	****0.117**
**R 43****	****	****	****   0.026****	****	****	****0.032**
**S 497****	****	****	****   0.028****	****	****	****0.035**
**STANLEY NORTH BASE   0.016****	****	****	****0.099**
**TRANSPORT AZ MK****	****   0.023****	****	****	****0.013**
**W 406****	****	****	****   0.020****	****	****	****0.004**
**WHAPORT AZ MK****	****   0.023****	****	****	****0.013**
**Z 19****	****	**** ****	****   0.024****	****	****	****0.095**

## Coordinate Comparison Summary

- NGS Executive Steering Committee set a 5 cm coordinate tolerance with the CORS to determine if a  readjustment of coordinates is performed
- The published horizontal positions fit well with the CORS adjustment-All under 4 cm
- The published ellipsoid heights do not fit well with the CORS adjustment-11 out of 29 exceed 5 cm
- Constrain horizontal positions & readjust ellipsoid heights

## Constrained Adjustment

- Constraints
- All published A & B Order Horizontal Positions
- Ellipsoid heights from the Minnesota and Montana FBN/CBN Surveys
- Minnesota’s were from the original HARN since the 5 cm coordinate tolerance was met in Minnesota
- Horizontal positions and ellipsoid heights for the CORS and ACS stations
- The ellipsoid height for BIL1 was an outlier and was not held

## Constrained versus CORS Adjustment

- Final Constrained Adjustment
- Largest Horizontal Residual 	**0.0384 m**
- Vertical Residual Spread	 **-0.0334 m to 0.0543 m**
- 						 * Single obs to MN
-                                                    station not included
- CORS Coordinates Constrained Adjustment
- Largest Horizontal Residual	**0.0269 m**
- Vertical Residual Spread	 **-0.0353 m to 0.0389 m**

## Ellipsoid Height Differences Final versus published

**Station Name****	****  EH Diff (m) Station Name****	****    EH Diff (m)**
**5N8 A            -0.024        J 474              ****-0.062****  **
**ARROWOOD          0.002        J 491              ****-0.067****       **
**D 477            -0.021        K 478              -0.026       **
**D 499            -0.024        M 9                -0.043       **
**DAISY            -0.046        MOHALL APT         ****-0.062****       **
**DAKOTA            0.013        PEMBINA APT AZ MK  -0.018       **
**E 486            -0.047        PIMPLE             ****-0.107****       **
**FAA D50 A        -0.032        R 43               -0.022**
**FAA HEI A        ****-0.063****        S 497              -0.041**
**FAA ND17 A       -0.034        STANLEY NORTH BASE ****-0.099**
**G 26             -0.012        TRANSPORT AZ MK    ****-0.079**
**G 304            -0.024        W 406               0.000**
**H 502            ****-0.071****        WHAPORT AZ MK      -0.044**
**ISN A            ****-0.121****        Z 19               ****-0.078**
**J 468            ****-0.078****           **

## Vertical Constrained Adjustment

- Constraints
- 33 NAVD 88 bench marks
- 3 NAVD 88 Height Mod GPS derived (CORS stations)
- 10 NAVD 88 GPS derived
- Readjusted
- 2 NAVD 88 Bench Marks (not superceded in IDB)
- 1 NAVD 88 GPS derived
- New
- 1 CORS (not published)
- 1 ACS (not published)
- 8 NAVD 88 GPS derived

## Vertical Adjustment Results

- Vertical Adjustment
- Largest Horizontal Residual 		**0.0155 m**
- Vertical Residual Spread	  **-0.0728 m to 0.1295 m**
- Comments
- It is not unusual to have residuals at the 10 cm level in the final constrained vertical adjustment
- Large residuals over long lines are caused by deficiencies in the leveling network and/or the geoid
- The adjusted NAVD 88 GPS derived heights are only published to 1 decimal place

## Statewide GPS Readjustment of Ellipsoid Heights in North Dakota

- Required to maintain consistency between the FBN and the GPS Network in North Dakota
- Performed in layers to reduce systematic errors by keeping the more accurately observed data separate from less accurately observed data
- Consisted of 3 layers in North Dakota

## Layers in North Dakota GPS Readjustment of Ellipsoid Heights

- Layer 1
- North Dakota A Order HARN (1996)
- Layer 2
- North Dakota B Order HARN (1996)
- Layer 3
- GPS1406-1st Order IBC Survey (1995-1997)
- GPS1556-1st Order-City of Grand Forks (2000)

## Results from Layer 1 North Dakota A Order HARN

- 9 Stations-All Published Horizontal Positions Fixed
- 5 From North Dakota
- 4 Participated in FBN Survey (Constrained EH’s)
- 1 New Ellipsoid Height for BSC BASE determined
- 2 From Minnesota (Constrained EH’s)
- 2 From Montana (Constrained EH’s)

## North Dakota HARN (1996)Readjustment Results (Layer 1)

- A Order-Free Adjustment
- Largest Horizontal Residual 	**0.0179 m**
- Vertical Residual Spread	 **-0.0263 m to 0.0294 m**
- A Order-Constrained Adjustment
- Largest Horizontal Residual	**0.0479 m**
- Vertical Residual Spread	 **-0.0355 m to 0.0521 m**

## Readjustment of A Order Compared to Original Constrained Adjustment 

- A Order-Constrained Readjustment
- Largest Horizontal Residual	**0.0479 m**
- Vertical Residual Spread	 **-0.0355 m to 0.0521 m**
- A Order-Constrained Adjustment (Original)
- Largest Horizontal Residual	**0.0422 m**
- Vertical Residual Spread	 **-0.0525 m to 0.0885 m**

## Readjusted Ellipsoid Height for BSC BASE

- Original Published Ellipsoid Height:   552.199 m
- Readjusted Ellipsoid Height:               552.161 m
- Difference						  0.038 m

## Results from Layer 2North Dakota B Order HARN

- Constrained Horizontal Positions
- 67 published values held
- 1 (DAMON-MT) readjusted-Better fit and more strongly determined in North Dakota than in Montana
- Constrained Ellipsoid Heights
- North Dakota
**29 from FBN + BSC BASE (Layer 1) held**
**14 Readjusted**
- Minnesota (8) & Montana (8) held
- South Dakota (8) not held but not re-published

## North Dakota HARN (1996)Readjustment Results (Layer 2)

- B Order-Free Adjustment
- Largest Horizontal Residual 	**0.0081 m**
- Vertical Residual Spread	 **-0.0258 m to 0.0304 m**
- B Order-Constrained Adjustment
- Largest Horizontal Residual	**0.0482 m**
- Vertical Residual Spread	 **-0.0557 m to 0.0469 m**

## Readjustment of B Order Compared to Original Constrained Adjustment

- B Order-Constrained Adjustment
- Largest Horizontal Residual	**0.0482 m**
- Vertical Residual Spread	 **-0.0557 m to 0.0469 m**
- B Order-Constrained Adjustment (original)
- Largest Horizontal Residual	**0.0245 m**
- Vertical Residual Spread	 **-0.1466 m to 0.0857 m**

## Ellipsoid Height DifferencesPublished versus Constrained

**Station Name****	****	****	****EH Difference (m)**
**BAP****	****	****	****	****0.042**
**BOUNDARY MON 729 CD US****	****0.033**
**DIK C****	****	****	****	****0.075**
**DVL E****	****	****	****	****0.014**
**FAA D04 A****	****	****	****0.087**
**FAA Y19 A****	****	****	****0.042**
**FAR G****	****	****	****	****0.010**
**GWR A****	****	****	****	****0.022**
**JMS C****	****	****	****	****0.028**
**L 283****	****	****	****	****0.062**
**P 101=CGS****	****	****	****0.064**
**S 266****	****	****	****	****0.008**
**SIBLEY 2****	****	****	****0.043**
**VALLPORT****	****	****	****0.021**

## Layer3-First Order Projects

- 2 Projects
- GPS1406-1st Order IBC Survey (1995-1997)
- GPS1556-1st Order-City of Grand Forks (2000)
- Adjusted together but are not connected

## Results from Layer 3North Dakota First Order Projects

- Constrained Horizontal Positions
- All 28 published values held
- Constrained Ellipsoid Heights
- North Dakota
**1 from FBN + S 266 (Layer 2) held**
**15 Readjusted**
- Minnesota-4 Non-FBN held
- Montana-2 from MT FBN + 3 Non-FBN held
- Canada -2 from Montana FBN held

## North Dakota First OrderReadjustment Results (Layer 3)

- First Order-Free Adjustment
- Largest Horizontal Residual 	**0.0431 m**
- Vertical Residual Spread	 **-0.0414 m to 0.0374 m**
- First Order-Constrained Adjustment
- Largest Horizontal Residual	**0.0442 m**
- Vertical Residual Spread	 **-0.0976 m to 0.1127 m**

## What Happened?

- Vertical Residual Spread	 **-0.0976 m to 0.1127 m**
- Caused by a poor fit between 2 stations from the Montana FBN (REGINA and MADOC) and data from GPS1406
- A constrained adjustment with trustworthy control such as the Montana FBN can detect systematic errors
- In this case data from GPS1406 (IBC Project) is suspected to be in error at the 10 cm level

## Ellipsoid Height DifferencesPublished versus Constrained

**Station Name****	****	****	****EH Difference (m)**
**BOUNDARY MON 584 CD US****	****	**** ****0.098****	****(from GPS1406)**
**BOUNDARY MON 591 CD US****	****	**** ****0.099****	****(from GPS1406)**
**BOUNDARY MON 621 CD US****	****	**** ****0.094****	****(from GPS1406)**
**BOUNDARY MON 646 CD US****	****	**** ****0.085****	****(from GPS1406)**
**E 332****	****	****	****	**** ****0.098****	****(from GPS1406)**
**G 261****	****	****	****	**** 0.003****	****(from GPS1556)**
**GF 1****	****	****	****	**** 0.000****	****(from GPS1556)**
**GF 2****	****	****	****	**** 0.001****	****(from GPS1556)**
**GF 3****	****	****	****	**** 0.001****	****(from GPS1556)**
**GF 4****	****	****	****	**** 0.000****	****(from GPS1556)**
**GF 5****	****	****	****	****-0.001****	****(from GPS1556)**
**GF 6****	****	****	****	****-0.002****	****(from GPS1556)**
**GF 7****	****	****	****	**** 0.001****	****(from GPS1556)**
**GF 9****	****	****	****	****-0.007****	****(from GPS1556)**
**The only change in control for GPS1556 was at S 266 from**
**   ****layer 2 (shift published minus final=0.008 m)- Thus small shifts **

## The National ReadjustmentGeneral Comments

- The CORS will provide the control
- Only GPS projects will participate
- The FBN/CBN Surveys are a key element since these are high accuracy (2 cm) surveys that tie the HARN to the CORS throughout the contiguous United States
- An adjustment analysis of each GPS project that contributes to the National Spatial Reference System is required prior to the National Readjustment

## The National ReadjustmentMore Comments

- Statewide GPS Readjustments provide extra information about the network on a state by state basis
- A readjustment plan that properly classifies all GPS projects comprising the network is required

## FBN/CBN Surveys

- Status:
- Observations complete for 48 contiguous states and the District of Columbia
- Reductions & Adjustment complete for 43 States and the District of Columbia
- IN, OH, KY, TN, & MO to go
- VA needs to be re-processed (Leica SR399 Antennas)

## Project Adjustment Analysis

- 3065 Projects complete
- Free Adjustment
- Residual Plot
- Outliers Rejected
- Connectivity to A/B Order Network Verified
- Summary sheet with Project Information Created
- 59,395 stations

## A lot of projects

**A lot of projects**

## Statewide GPS Readjustments

- Complete for 36 of 43 States and DC
- Readjustment of EH’s and/or Positions (5cm tolerance)
- Layered Adjustment Approach Used
- States not Completed
- MN & GA-Met 5 cm tolerance set by ESC
- CA-Requires special analysis
- SD, IL, KS & IA-Recently loaded

## Centralization of Project Information

- Master File Created
- Information from Individual Projects
- Information from State GPS Readjustment

## Example

**OBS_SOURCE   |A  |B  |1  **
**‐‐‐‐‐‐‐‐‐‐‐‐‐ ‐‐‐ ‐‐‐ ‐‐‐ ****	****	****ND HARN-B Order-1996-****	****	****	****	****	****Excellent residuals-3 cm ****	****	****	****	****	****or less**
**GPS1048/B    |  2|  6|  0  MN****	****No GPS readjustment ****	****	****	****	****	****	****performed in this state**
**GPS1048/B    |  2|  6|  0  SD****	**
**GPS1048/B    |  5| 39|  0  ND****	****Level 2 of 3 in ND GPS ****	****	****	****	****	****readjustment**
**GPS1048/B    |  6|  2|  0  MT****	****All either in FBN or in ****	****	****	****	****	****ID/MT HARN-Not included ****	****	****	****	****	****in ID/MT GPS Readjustment **

## Concept of Operation

- Adjust software will be used
- Layered Approach (except possibly CA)
- National Layers (Higher Order Projects)
- Regional Layers (UDN/First Order or Lower)
- Coordinates Produced and Published for both NAD83 (NSRS) and ITRF
- Adjustment in NAD83-Transformed to ITRF
- Canadian Data Integrated at FBN/CBN Layer
- Network and Local Accuracies also Produced

## Local and Network Accuracies

- Local Accuracy of a control point:
- A value that represents the uncertainty of its coordinates relative to other directly connected, adjacent control points at the 95-percent confidence level
- An approximate average of the individual local accuracy values between this control point and other observed control points used to establish its coordinates

## Local and Network Accuracies

- Network accuracy of a control point
- A value that represents the uncertainty of its coordinates with respect to the geodetic datum at the 95-percent confidence level
- Datum is considered to be best expressed by the Continuous Operating Reference Stations (CORS)
- Local and Network accuracy values at CORS sites are considered to be infinitesimal (approach zero)
- These accuracies will be implemented with the National Readjustment

## National Layers

- N0-The National CORS coordinate set
- N1-The FBN/CBN projects (3209 stations) (ND-FBN/CBN)
- N2-A & B Order projects with CORS ties (2203 stations)
- FAACORS-FAA projects with CORS ties (2288 stations)
- N3-A Order projects without CORS ties (292 stations)
- ND-Layer 1-A Order HARN (1996)
- N4-B Order projects without CORS ties (6169 stations)
- ND-Layer 2-B Order HARN (1996)
- N5-Combination B & 1st Order projects without CORS ties
- 	  and 1st Order Projects with CORS ties (3721 stations)
- AIR-Lower Order FAA Projects without CORS ties (7593	stations)

## Regional Layers

- UDN Projects (First and Lower)
- 7 Geographic Regions
- 3 Categories
- R1-Recent (Post 1992)-Residuals Under 7 cm
- R2-Residuals Under 15 cm
- R3-Either Large Residuals or Weak Geometry but
-          with some redeeming value to the community

## Region 1

**Florida Alabama and Georgia**
**   ****Proj R1   Sta R1   Proj R2   Sta R2   Proj R3   Sta R3 **
**FL      63     2693****	****       13     1280        14     1002**
**AL       0        0        34     3584****	****	****0        0**
**GA      **_** 9**_**    **_**  644**_**        **_** 3**_**   **_**   201**_**       **_**  2**_**     **_** 227**_
**        ****72     3337        50     5065****	****      16     1229**

## Region 2

**North Carolina and South Carolina**
**	****Proj R1****	****Sta R1   Proj R2****	****Sta R2   Proj R3****	****Sta R3 **
**SC****	****     44****	****  1826****	****  13****	****  1142         8****	****   575**
**NC****	****    **_** 75**_**	****  **_**3315**_**        **_**11**_**	****  **_** 568**_**	****  **_** 6**_**	****   **_**154**_
**      ****119****	****  5141****	****  24****	****  1710****	****  14****	****   729**

## Region 3

**VA, MD, DC, DE, WV, NJ, PA, NY, CT, MA, RI, NH, VT & ME**
**	****Proj R1   Sta R1     Proj R2   Sta R2    Proj R3****	**** Sta R3 **
**VA****	****     14****	**** 966           3       65         10     547**
**MD****	****     27     1406           5      304          5      32**
**DC****	****      1****	****  11           1       11 ****	****     0       0**
**DE       1        8****	****	****0        0          0       0**
**WV       1****	****  20****	****	****0        0          1       7**
**NJ****	****     33     1199****	****	****2       21          0       0**
**PA****	****     12      267****	****	****0        0          2      87**
**NY****	****      4      637           2       31****	****     0       0**
**CT       0        0****	****	****0        0****	****     0       0**
**MA       2       31****	****	****0        0****	****     0       0**
**RI       3       87****	****	****0        0          0       0**
**NH       0        0  ****	****	****0        0****	****     0       0**
**VT****	****     10      613****	****	****0        0   ****	****     0       0**
**ME****	****    **_**  3**_**     **_**  40**_**          **_** 0**_**      **_**  0**_**         **_** 0**_**     **_**  0**_
**	****    ****111****	****5285          13      432         18     673**

## Region 4

**MS, LA, AR, TN, KY, MO, IL, IN, OH, MI, WI & IA**
**	****Proj R1     Sta R1     Proj R2     Sta R2     Proj R3     Sta R3 **
**MS       2         34           1         16           0          0**
**LA       6        170           2        453           9        304**
**AR       1         88           0          0           1        260**
**TN       0          0           3        227           0          0**
**KY       3        406           4        129           0          0**
**MO       4        504           5        106           1        143**
**IL      22        998           3        291           1        344**
**IN       0          0           2         14           0          0**
**OH      25       1653          10        760           5        248**
**MI      13        421          12        276           1         88**
**WI       6        540           2        118           0          0**
**IA      **_** 1**_**       **_**  16**_**         **_**  0**_**       **_**   0**_**          **_** 0**_**       **_**   0**_
**        ****83       4830          44       2390          18       1387**

## Region 5

**TX, OK, KS, NE, SD, ND & MN**
**	**** ****Proj R1   Sta R1     Proj R2   Sta R2     Proj R3   Sta R3 **
**TX       3      166           2      175           2       35**
**OK       0        0           0        0           1       23**
**KS       0        0           1       73           0        0**
**NE       0        0           0        0           0        0**
**SD       1       28           0        0           1       11**
**ND       2       26           0        0           1       45**
**MN      **_**81**_**     **_**3636**_**           **_**1**_**      **_** 16**_**           **_**3**_**      **_**143**_
**        ****86     3856           4      264           8**      257
- ND Layer 3 (GPS1406 & GPS1556) in R1
- GPS345-Mandan Project-1st Order-Private Submitter-1991-horizontal residuals up to 27 cm and vertical residuals up to 25 cm in R3

## Region 6

**NM, AZ, CO, UT, NV, WY, MT, ID, OR & WA**
**	****Proj R1     Sta R1     Proj R2     Sta R2     Proj R3     Sta R3 **
**NM       3        185           0          0           0          0**
**AZ       1         25           5        227           1         30**
**CO      60       1155           7        198           6        139**
**UT       0          0           0          0           3         36**
**NV       0          0           0          0           0          0**
**WY       0          0           0          0           1          6**
**MT       8         46           5         29           1          5**
**ID       4         25           3         42           1         22**
**OR       3         19           0          0           3         74**
**WA      **_** 8**_**       **_** 530**_**          **_** 1**_**        **_** 46**_**          **_** 5**_**        **_**150**_
**        ****87       1985          21        542          21        462**

## Region 7

**California**
**Requires separate analysis**
**Projects not yet included in Master Plan Yet**
**Breakdown:**
**	****	****Number of Projects****	****   Number of Stations**
**	****N2****	****	****	****24****	****	****	****	****355**
**	****FAACORS****	****	****	****25****	****	****	****	**** 84**
**	****N3****	****	****  ****	**** 1****	****	****	****	****  9**
**	****N4****	****	****	****14****	****	****	****	****258**
**	****N5****	****	****	****23****	****	****	****	****335**
**	****AIR****	****	****	****49****	****	****	****	****273**
**	****UDN****	****          ****	****70****	****	****           1529**

## TRASH

- Projects Not Recommended for Inclusion
- 149 Projects with 9903 stations
- Many Third Order FAA Projects from 1980’s
- Some Projects that have no ties to the Network
- Includes Original TN HARN (Macrometer Data)
- Included Original Eastern Strain Network Project

## Trashed Projects in North Dakota

**GPS138-First Order IBC Project-1988-horizontal residuals up to 6 dm and 4 dm vertical**
**GPS194-Second and Third Order FAA Project-1989 to 1990-horizontal residuals up to 7 dm and 4 dm vertical **
**GPS331-Third Order FAA-1991-horizontal residuals up to 3 dm and 2 dm vertical**

## Ongoing Tasks

- Project Level Analysis (Free Adjustments)
- State GPS Readjustments (as required)
- Master Plan Updates-Layer Assignments
- Airport Layer Verification

## New Tasks

- California Data Analysis
- Identify and Resolve Project Weighting Scheme Deficiencies
- Facilitate the Implementation of Local and Network Accuracies in the National Readjustment

## Time-line for National Readjustment 

- Proposed starting date –June 2005-Some unexpected but reasonable delays have been factored in
- Time-lines for new tasks are flexible but:
**MUST BE COMPLETED BY JUNE 2005**
**	****	****	****	****	**** ****OR**
**NATIONAL READJUSTMENT ALSO DELAYED**
**	****	****	****	****	**

## Contingency Option

**In case of large delays in New Tasks/Software**
**Perform Statewide GPS Readjustments of both horizontal positions and ellipsoid heights**
**Approved by Executive Steering Committee on September 24, 2003**

## Time-line for National Readjustment Positions and Ellipsoid Heights

- All new tasks completed by 06/2005
- National Layers
- N1-06/2005-12/2005
- N2 & FAACORS-01/2006-02/2006
- N3-03/2006
- N4-04/2006-05/2006
- N5-06/2006-07/2006
- AIR-08/2006-10/2006

## Time-line for National Readjustment Positions/Ellipsoid Heights (continued)

- Regional Layers
- Layers 1-7 (6 weeks for each region)
- November 2006 through September 2007
- Project Report
- 3 Months-October 2007 through December 2007
- Could be sped up by using more personnel-Up to 3 regions could be worked on simultaneously

## Time-line for Project Submissions

- Higher Order Projects
- Stop 2 months prior to the completion of N1
- Proposed:  November 1, 2005
- Resume after all national layers are complete
- Proposed:  November 1, 2006
- Lower Order Projects (UDN)
- Stop 6 weeks prior to the start of a region
- Resume after a region is complete

## Post National Readjustment

- A transformation model for “classical” non-GPS stations and GPS stations that were excluded from the National Readjustment will be needed
- New adjustment procedures need to be developed that incorporate local and network accuracies
- Areas outside the contiguous US may need to be readjusted (ie Alaska & Hawaii)
- A reference frame maintenance strategy (NAD83, ITRF, either or both) needs to be developed

## Expected coordinate shifts in North Dakota after National Readjustment

- Test Designed = Contingency Option
- Re-do North Dakota FBN (N1) readjusting both positions and Ellipsoid Heights/Hold CORS
- Re-do North Dakota A Order (N3)
- Re-do North Dakota B Order (N4)
- Re-do GPS1406 & GPS1556 (R1)

## North Dakota FBNPublished – CORS Constrained

**Station Name****	****Position Diff (m)****	****EH Diff (m)**
**5N8****	****	****	****0.018****	****	****	****-0.004**
**ARROWWOOD****	****	****0.026****	****	****	****-0.006**
**D 477****	****	****	****0.021****	****	****	****-0.012**
**D 499****	****	****	****0.023****	****	****	****-0.004**
**DAISY****	****	****	****0.013****	****	****	****-0.004**
**DAKOTA****	****	****0.022****	****	****	****-0.026**
**E 486****	****	****	****0.020****	****	****	****-0.007**
**FAA D50 A****	****	****0.022****	****	****	****-0.015**
**FAA HEI A****	****	****0.026****	****	****	****-0.029**
**FAA ND17 A****	****	****0.021****	****	****	**** 0.005**
**G 26****	****	****	****0.029****	****	****	****-0.006**
**G 304****	****	****	****0.015****	****	****	****-0.006**
**H 502****	****	****	****0.021****	****	****	****-0.008**
**ISN A****	****	****	****0.018****	****	****	****-0.014**
**J 468****	****	****	****0.014****	****	****	****-0.004**

## North Dakota FBNPublished – CORS Constrained

**Station Name****	****	****Position Diff (m)****	****	****EH Diff (m)**
**J 474****	****	****	****   0.016****	****	****	****-0.001**
**J 491****	****	****	****   0.014****	****	****	****-0.009**
**K 478****	****	****	****   ****0.024****	****	****	****-0.002**
**M 9****	****	****	****   0.017****	****	****	****-0.009**
**MOHALL APT****	****	****   0.013****	****	****	****-0.003**
**PEMBINA APT AZ MK****	****   ****0.022****	****	****	****-0.007**
**PIMPLE****	****	****   0.015****	****	****	****-0.009**
**R 43****	****	****	****   ****0.026****	****	****	****-0.013**
**S 497****	****	****	****   ****0.028****	****	****	**** 0.002**
**STANLEY NORTH BASE   0.016****	****	****	****-0.003**
**TRANSPORT AZ MK****	****   ****0.025****	****	****	**** 0.000**
**W 406****	****	****	****   ****0.020****	****	****	****-0.008**
**WHAPORT AZ MK****	****   ****0.022****	****	****	**** ****0.027**
**Z 19****	****	**** ****	****   ****0.025****	****	****	****-0.017**

## North Dakota A Order HARNPublished – Test Constrained

**BSC BASE**
**Horizontal Position Difference****	****  0.014 m**
**Ellipsoid Height Difference****	**** ****-0.028 m**

## North Dakota B Order HARNPublished – Test Constrained

**Station Name****	****Position Diff (m)****	****EH Diff (m)**
**BAP****	****	****	****0.018****	****	****	****-0.027**
**BOUNDARY MON 729****	****0.017****	****	****	****-0.005**
**DIK C****	****	****	****0.018****	****	****	****-0.025**
**DVL E****	****	****	****0.018****	****	****	****-0.008**
**FAA D04 A****	****	****0.025****	****	****	****-0.010**
**FAA Y19 A****	****	****0.018****	****	****	****-0.026**
**FAR G****	****	****	****0.025****	****	****	****-0.012**
**GWR A ****	****	****0.026****	****	****	****-0.008**
**JMS C ****	****	****0.020****	****	****	****-0.003**
**L 283 ****	****	****0.013****	****	****	****-0.003**
**P 101=CGS****	****	****0.025****	****	****	****-0.027**
**S 266****	****	****	****0.018****	****	****	****-0.012**
**SIBLEY 2****	****	****0.018****	****	****	****-0.026**
**VALLPORT****	****	****0.020****	****	****	****-0.001**

## North Dakota First Order Published – Test Constrained

**Station Name****	****Position Diff (m)****	****EH Diff (m)**
**BOUNDARY MON 584****	****0.001****	****	****	**** 0.000**
**BOUNDARY MON 591****	****0.002****	****	****	**** 0.000**
**BOUNDARY MON 621****	****0.003****	****	****	**** 0.000**
**BOUNDARY MON 646****	****0.007****	****	****	**** 0.000**
**E 332****	****	****	****0.002****	****	****	**** 0.000**
**G 261****	****	****	****0.018****	****	****	****-0.009**
**GF 1****	****	****	****0.016****	****	****	****-0.007**
**GF 2****	****	****	****0.018****	****	****	****-0.008**
**GF 3****	****	****	****0.018****	****	****	****-0.004**
**GF 4****	****	****	****0.019****	****	****	****-0.008**
**GF 5****	****	****	****0.018****	****	****	****-0.004**
**GF 6****	****	****	****0.019****	****	****	****-0.006**
**GF 7****	****	****	****0.019****	****	****	****-0.007**
**GF 8****	****	****	****0.020****	****	****	****-0.002**
**GF 9****	****	****	****0.021****	****	****	****-0.006**

## What will the changes be?

- Changes in horizontal positions and ellipsoid
- heights will be less then 3 cm after the National
- Readjustment in North Dakota

## THAT’S ALL FOLKS !!!