Knowing where you are and where

1
Knowing where you are and where
other things are anytime, anyplace!
2
National Spatial Reference System

• The National Spatial Reference System (NSRS) is a
  consistent national coordinate system that
  specifies latitude, longitude, height, scale,
  gravity, and orientation throughout the Nation,
  as well as how these values change with time.

3
Imporving Positional Accuracy
REFERENCE TIME NETWORK
LOCAL FRAME SPAN ACCURACY
ACCURACY
NAD 27 1927-1986 10 Meters
First-Order (1 part in 0.1 million)
NAD 83 1986-1990 1 Meter
First-Order (1 part in 0.1 million)
HARN 1987-1997 0.1 Meter
B-Order (1 part in 1 million)

A-Order (1 part in 10 million)
4
(No Transcript)
5
Continuously Operating Reference Stations
6
CORS Advantages

• 3-dimensional (Lat., Long., Ellipsoid Ht. or
  X, Y, Z)

• Eliminates control points reconnaissance (time
  and money).

• Eliminates needing people and equipment at a
  control points.

• Direct tie to National Spatial Reference System
  (NSRS).

• CORS positions and velocities are available in
  both NAD 83 and ITRF coordinate systems.

• CORS positions are of the highest accuracy.

• CORS positions are continuously monitored and
  will be updated if the site moves.

7
CORS Data Quality
8
U.S. Coast Guard Sites

• 20 of National CORS (80 of 400)
• 27 of UFCORS Requests (15,400 of 56,994 in
  July)
• 52 Sites With Met Sensors
• Highly Reliable
• Easy to Add New Ones
• Economies of Partnership

9
CORS Data Access

• Hardcopy Data Sheets
• Floppy Disks
• CD-ROMS
• Bulletin Board Service
• Internet FTP and Web
• UFCORS, CORSAGE, OPUS, Cooperative CORS
• Objective - Easier, Cheaper, Faster Access

10
UFCORS

• User Friendly CORS
• Value-added Service
• Removes Underlying Complexity
• Customized Data Product

11
NGS Home Page www.ngs.noaa.gov
12
(No Transcript)
13
UFCORS Page
14
(No Transcript)
15
(No Transcript)
16
CORSAGE

• CORSAGE - CORS Amiable Geographic Environment
• Meta-data Data about data.
• Address www.ngs.noaa.gov/CORS

17
(No Transcript)
18
(No Transcript)
19
CORSAGE Meta-data

• Coordinates (positions velocities)
• Data availability profiles (charts showing times
  for which data has been collected)
• Data sheets (descriptive information)
• Log files (descriptive information)
• RINEX Data (observation files)
• Time series of positional coordinates

20
OPUS

• On-line Positioning User Service

• Provide GPS users faster easier access to the
  National Spatial Reference System (NSRS)

21
(No Transcript)
22
How Does OPUS Work?

• Submit RINEX file through NGS web page

• Processed automatically with NGS computers
  software

• With respect to 3 suitable National CORS

• Solution via email (usually in minutes)

23
OPUS Web Page
24
OPUS - Select Reference Site(s)
25
OPUS Guidelines

• Must submit dual-frequency (L1/L2) data

• Must submit at least 2 hrs of data

• No kinematic/Rapid Static

• No Glonass

• Correct vertical requires
• antenna type
• antenna height

26
OPUS Computing Positions

• NGS PAGES software

• Ionosphere free

• Tropospheric scale height adjusted

• Fixed ambiguities

• Average solution to 3 suitable CORS

• ITRF and NAD83 positions returned

27
OPUS Output
28
Cooperative CORS

• The Data are Located on the Participants Server
• Accessible via a Link on the NGS CORS Web Site
• Position is Computed with NGS Software
• Position is Sanctioned by NGS to be consistent
  with the NSRS

29
(No Transcript)
30
(No Transcript)
31
(No Transcript)
32
(No Transcript)
33
(No Transcript)
34
UFCORS Usage Statistics
35
OPUS Usage Statistics
36
Future Directions

• UFCORS
• Web Service Computer Friendly CORS
• CORSAGE
• GSAC Meta data.
• OPUS
• Better treatment of RINEX-2 header errors is
  being implemented. Some translators are not
  compliant with the RINEX-2 standard.
• Single frequency data processing is being
  considered.

37
QUESTIONS?
http//www.ngs.noaa.gov/OPUS/ opus_at_ngs.noaa.gov