# Presentation: 173066

## National Readjustment 

- Kathy Milbert

## 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)
- 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)
- N4-B Order projects without CORS ties (6169 stations)
- 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

## 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

## 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

## THAT’S ALL FOLKS !!!